SolidsWiki - User contributions [en]

Slurry Pumps

2012-04-20T09:58:44Z

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File:Slurry pump2.jpg

2012-04-20T09:58:31Z

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File:Slurry pump1.jpg

2012-04-20T09:58:02Z

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Coaters

2012-04-16T10:28:24Z

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[[Category:Particle Formation]]{{Knoppen}}
<noinclude></noinclude>

[[File:Coaters.jpg|thumb|right|Coater]]

'''Coaters''' apply coatings to a surface. A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance. In other cases, in particular in printing processes and semiconductor device fabrication (where the substrate is a wafer), the coating forms an essential part of the finished product. Coating and printing processes involve the application of a thin film of functional material to a substrate, such as paper, fabric, film, foil or sheet stock.

Coatings may be applied as liquids, gases or solids. Coatings can be measured and tested for proper opacity and film thickness by using a drawdown card.

==Types of Coaters==

*[[Powder Coaters]]
*[[Liquid Coaters]]
*[[Gas Coaters]]

Coaters

2012-04-16T10:27:58Z

Mark:

[[Category:Particle Formation]]{{Knoppen}}
<noinclude></noinclude>

[[File:Coaters.jpg|thumb|right|Coater]]

'''Coaters''' apply coatings to a surface. A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance. In other cases, in particular in printing processes and semiconductor device fabrication (where the substrate is a wafer), the coating forms an essential part of the finished product. Coating and printing processes involve the application of a thin film of functional material to a substrate, such as paper, fabric, film, foil or sheet stock.

Coatings may be applied as liquids, gases or solids. Coatings can be measured and tested for proper opacity and film thickness by using a drawdown card.

==Types of Coaters==
[[Powder Coaters]]
[[Liquid Coaters]]
[[Gas Coaters]]

Coaters

2012-04-16T10:23:11Z

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Coaters

2012-04-16T10:22:46Z

Mark:

[[Category:Particle Formation]]{{Knoppen}}
<noinclude></noinclude>

[[File:Coaters.jpg|thumb|right|Coater]]

'''Coaters''' or coating machines apply coatings to a surface. A coating is a covering]] that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance. In other cases, in particular in printing processes and semiconductor device fabrication (where the substrate is a wafer), the coating forms an essential part of the finished product. Coating and printing processes involve the application of a thin film of functional material to a substrate, such as paper, fabric, film, foil or sheet stock.

Coatings may be applied as liquids, gases or solids. Coatings can be measured and tested for proper opacity and film thickness by using a drawdown card.

File:Coaters.jpg

2012-04-16T10:22:37Z

Mark:

Agitated Ball Mills

2012-04-13T14:47:17Z

Mark:

[[Category:Particle Size Reduction]]{{Knoppen}}
<noinclude></noinclude>

[[File:Agitated_ball_mill.jpg|thumb|right|Agitated Ball Mills]]

'''Agitated Ball Mills''' are a variation of regular [[Ball Mills]] and are often used for the grinding of wet media.

Most of the agitated media mills are used for slurries, only a minority is in industrial use for the fine grinding of dry powders. The grinding energy is transferred into the media by agitation with a rotating stirrer. Also combined agitation by stirrer and rotating body is known. The grinding chamber arrangement and shaft direction is vertical and there are three basically different mill types. The so called tower-mill has a screw-type rotor which lifts the grinding media and actually uses the gravity as driving force for media motion. This mill cannot be operated with very small media.

Second type is an agitated media mill with stationary grinding media filling; material transport is done by gravity or pneumatically. The third type is operated with a circulating media filling; material and powder are flowing through the agitated mill chamber. These two types of dry agitated media mills create high kinetic forces on the media and can be used with very small ball sizes. The grinding mechanism can be influenced by variation of the agitator speed and the ratio of media filling. High rotation speed and low media filling level effect a tendency to impact stress, whereas a high filling ratio of beads shifts the mechanism more to shear stress. In contrast to agitated wet ball mills, dry ball mills are typically low speed mills with predominant shear grinding.

File:Agitated ball mill.jpg

2012-04-13T14:47:04Z

Mark:

Agitated Ball Mills

2012-04-13T14:45:41Z

Mark:

[[Category:Particle Size Reduction]]{{Knoppen}}
<noinclude></noinclude>

'''Agitated Ball Mills''' are a variation of regular [[Ball Mills]] and are often used for the grinding of wet media.
Most of the agitated media mills are used for slurries, only a minority is in industrial use for the fine grinding of dry powders. The grinding energy is transferred into the media by agitation with a rotating stirrer. Also combined agitation by stirrer and rotating body is known. The grinding chamber arrangement and shaft direction is vertical and there are three basically different mill types. The so called tower-mill has a screw-type rotor which lifts the grinding media and actually uses the gravity as driving force for media motion. This mill cannot be operated with very small media.
Second type is an agitated media mill with stationary grinding media filling; material transport is done by gravity or pneumatically. The third type is operated with a circulating media filling; material and powder are flowing through the agitated mill chamber. These two types of dry agitated media mills create high kinetic forces on the media and can be used with very small ball sizes. The grinding mechanism can be influenced by variation of the agitator speed and the ratio of media filling. High rotation speed and low media filling level effect a tendency to impact stress, whereas a high filling ratio of beads shifts the mechanism more to shear stress. In contrast to agitated wet ball mills, dry ball mills are typically low speed mills with predominant shear grinding.

Net Weighers

2012-04-13T14:13:39Z

Mark:

[[Category:Weighing, Dosing]]{{Knoppen}}
<noinclude></noinclude>

[[File:Net_Weigher.jpg|thumb|right|Net Weigher]]
[[File:Net_Weigher_installation.jpg|thumb|right| Net Weigher installation]]

[[Net Weighers]] are bulk weighing machines that weighs the product in a vessel above the bag. Gross weight is a term that generally is found in commerce or trade applications, and refers to the total weight of a product and its packaging.

==Compared to [[Gross Weighers]]==

*Very fast. The next weighing cycle can start as soon as the weigher doors have closed, whilst the currently filled bag is being dropped and a fresh one fitted into the clamps. Nett weighers will operate at 10 cycles per minute minimum for most materials, and 15 cycles per minute with excellent accuracy can be achieved with certain materials and bag weights.

*Very accurate. The inflight amount of material is smaller than a gross weigher, due to a shorter distance between the feeder outlet and the weigh hopper. The weigher is always a constant distance from the feeder outlet, ensuring repeatability. There is also virtually no opportunity for the operator to tamper with the weigher parts during filling.

*Large headroom required. For most nett weighing systems, at least 5 or 6 metres headroom is required, which would include a 1000 Litre surge hopper at the top.

*More expensive. A weigh hopper and more ancillaries / metal parts are required compared to a gross weigher, which increases cost.

File:Net Weigher installation.jpg

2012-04-13T14:12:59Z

Mark:

File:Net Weigher.jpg

2012-04-13T14:12:35Z

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Gross Weighers

2012-04-13T14:11:22Z

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[[Category:Weighing, Dosing]]{{Knoppen}}
<noinclude></noinclude>

[[File:Bulk_weighers.gif|thumb|right|Gross Weigher placement]]
[[File:Gross_weigher1.jpg|thumb|right|Gross Weigher]]
[[File:Gross_weigher2.jpg|thumb|right|Gross Weigher]]

'''Gross Weighers''' are a type of weighting machines that weigh the Product in the bag. Note that most electronic weighing in the bag will tare the empty bag off and technically be a nett weigher.
Net weight refers to the weight of the product alone, discounting the weight of its container or packaging

==Compared to [[Net Weighers]]==

*Low headroom. Discounting the height of the top surge hopper, a gross weigher and feeder can take up less than 2 metres of height (including the conveyor).

*Lower cost.No weigh hopper is used and therefore less ancillaries / metal parts are required, reducing the cost. Slower than nett weighers. The next weighing cycle cannot start until a fresh bag is fitted into the clamps. Generally the speeds that can be achieved are up to 8 cycles per minute with good accuracy, depending on the material. For an application where accuracy is of less importance, higher speeds can be achieved, of up to 12 cycles per minute (may involve fast feed only).

*Slightly less accurate. The operator can fit the bag at an angle, which will affect the inflight amount. The inflight amount of material is higher due to a longer drop between the feeder outlet and the bag. It is easy for the operator to tamper with the weigher parts during filling, which will affect cut-off and the subsequent inflight adjustment for the next weighing cycle.

*Can be in a mobile format more easily than [[Net Weighers]].

File:Gross weigher2.jpg

2012-04-13T14:11:07Z

Mark:

File:Gross weigher1.jpg

2012-04-13T14:10:43Z

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File:Bulk weighers.gif

2012-04-13T14:09:33Z

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Gross Weighers

2012-04-13T13:59:51Z

Mark:

[[Category:Weighing, Dosing]]{{Knoppen}}
<noinclude></noinclude>

[[Gross Weighers]] are a type of weighting machines that weigh the Product in the bag. Note that most electronic weighing in the bag will tare the empty bag off and technically be a nett weigher.
==Compared to [Net Weighers]==

Low headroom. Discounting the height of the top surge hopper, a gross weigher and feeder can take up less than 2 metres of height (including the conveyor). Lower cost.No weigh hopper is used and therefore less ancillaries / metal parts are required, reducing the cost. Slower than nett weighers. The next weighing cycle cannot start until a fresh bag is fitted into the clamps. Generally the speeds that can be achieved are up to 8 cycles per minute with good accuracy, depending on the material. For an application where accuracy is of less importance, higher speeds can be achieved, of up to 12 cycles per minute (may involve fast feed only). Slightly less accurate. The operator can fit the bag at an angle, which will affect the inflight amount. The inflight amount of material is higher due to a longer drop between the feeder outlet and the bag. It is easy for the operator to tamper with the weigher parts during filling, which will affect cut-off and the subsequent inflight adjustment for the next weighing cycle. Can be in a mobile format more easily than nett weighers.

Pumps

2012-03-15T12:37:38Z

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Pumps

2012-03-15T12:31:26Z

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Pumps

2012-03-15T12:30:28Z

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Membrane Pumps

2012-03-15T11:31:49Z

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Diaphragm Pumps

2012-03-15T11:31:39Z

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Membrane Pumps

2012-03-15T11:31:05Z

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Diaphragm Pumps

2012-03-15T11:30:42Z

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Powder Pumps

2012-03-15T11:18:55Z

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Pumps

2012-03-15T11:18:49Z

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Pumps

2012-03-15T11:18:00Z

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Powder Pumps

2012-03-15T11:17:56Z

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Powder Pumps

2012-03-15T11:16:50Z

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Powder Pumps

2012-03-15T11:15:58Z

Mark:

[[Category:Pumps]]{{Knoppen}}
<noinclude></noinclude>
[[Image:Jet_pump.jpg|thumb||right|A jet pump]]

A '''pump''' displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps.

==Types==
===[[Positive Displacement Pumps]]===
[[Image:Drehkolbenpumpe.jpg|thumb||right|A lobe pump]]
[[Image:423px-Common_Lobe_Pump.png|thumb|right|upright|lobe pump internals]]
[[Image:Two_moving_spirals_scroll_pump.gif|thumb|Mechanism of a scroll pump]]

A positive displacement pump causes a powder to move by trapping a fixed amount of it and then forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps work using an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pump as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

==== Positive Displacement Pump behavior and safety ====
Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, will in theory produce the same flow at a given speed (RPM) no matter what the discharge pressure. Thus, positive displacement pumps are constant flow machines. However due to a slight increase in internal leakage as the pressure increases, a truly constant flow rate cannot be achieved.

A positive displacement pump must not be operated against a closed valve on the discharge side of the pump, because it has no shut-off head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase, until the line bursts or the pump is severely damaged, or both.

A relief or safety valve on the discharge side of the positive displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve should in general only be used as a safety precaution, an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended.

==== Positive Displacement Types ====
[[Image:Lysholm_screw_rotors.jpg|thumb|upright|Screw pump]]
A positive displacement pump can be further classified according to the mechanism used to move the powder:

* '''Rotary-type''' positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, helical twisted roots (e.g. the Wendelkolben pump) or powder ring vacuum pumps.
* '''Reciprocating-type''' positive displacement: piston or diaphragm pumps.
* '''Linear-type''' positive displacement: Rope pump|rope pumps and chain pumps.

===== Rotary Positive Displacement Pumps =====
[[File:220px-Rotary_vane_pump.svg.png|thumb|Rotary vane pump]]
Positive displacement rotary pumps are pumps that move powder using the principles of rotation. The vacuum created by the rotation of the pump captures and draws in the powders.

'''Advantages:''' Rotary pumps are very efficient because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

'''Drawbacks:''' Positive displacement rotary pumps also have their weaknesses. Because of the nature of the pump, the clearance between the rotating pump and the outer edge must be very close, requiring that the pumps rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the powders will cause erosion. Rotary pumps that experience such erosion eventually show signs of enlarged clearances, which allow powder to slip through and reduce the efficiency of the pump.

===== Reciprocating Positive Displacement Pumps =====

Reciprocating-type pumps require a system of suction and discharge valves to ensure that the powder moves in a positive direction. Pumps in this category range from having "simplex" one cylinder, to in some cases "quad" (four) cylinders or more. Most reciprocating-type pumps are "duplex" (two) or "triplex" (three) cylinder. Furthermore, they can be either "single acting" independent suction and discharge strokes or "double acting" suction and discharge in both directions. The pumps can be powered by air, steam or through a belt drive from an engine or motor. This type of pump was used extensively in the early days of steam propulsion (19th century) as boiler feed water pumps. Reciprocating pumps are now typically used for pumping highly viscous powders including concrete and heavy oils, and special applications demanding low flow rates against high resistance.

These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pumps as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

Typical reciprocating pumps are:
* [[Diaphragm Pumps]] - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder.

==== Various Positive Displacement Pumps ====
The positive displacement principle applies in the following types of pumps:

* [[Progressive Cavity Pumps]]
* [[Diaphragm Pumps]]
* [[Screw Pumps]]
* [[Peristaltic Pumps]]
* [[Piston Pumps]]
* [[Vertical Pumps]]
* [[Well Pumps]]
* [[Worm Pumps]]
* [[Worm Pumps]]
* [[Press Pumps]]
* [[Sump Pumps]]
* [[Peristaltic Pumps]]

Positive Displacement Pumps

2012-03-15T11:15:43Z

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Pumps

2012-03-15T11:13:32Z

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Pumps

2012-03-15T11:13:05Z

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Pumps

2012-03-15T11:11:20Z

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Pumps

2012-03-15T11:08:00Z

Mark:

[[Category:Pumps]]{{Knoppen}}
<noinclude></noinclude>
[[Image:Jet_pump.jpg|thumb||right|A jet pump]]

A '''pump''' displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps.

==Types==
===[[Positive Displacement Pumps]]===
[[Image:Drehkolbenpumpe.jpg|thumb||right|A lobe pump]]
[[Image:423px-Common_Lobe_Pump.png|thumb|right|upright|lobe pump internals]]
[[Image:Two_moving_spirals_scroll_pump.gif|thumb|Mechanism of a scroll pump]]

A positive displacement pump causes a powder to move by trapping a fixed amount of it and then forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps work using an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pump as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

==== Positive Displacement Pump behavior and safety ====
Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, will in theory produce the same flow at a given speed (RPM) no matter what the discharge pressure. Thus, positive displacement pumps are constant flow machines. However due to a slight increase in internal leakage as the pressure increases, a truly constant flow rate cannot be achieved.

A positive displacement pump must not be operated against a closed valve on the discharge side of the pump, because it has no shut-off head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase, until the line bursts or the pump is severely damaged, or both.

A relief or safety valve on the discharge side of the positive displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve should in general only be used as a safety precaution, an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended.

==== Positive Displacement Types ====
[[Image:Lysholm_screw_rotors.jpg|thumb|upright|Screw pump]]
A positive displacement pump can be further classified according to the mechanism used to move the powder:

* '''Rotary-type''' positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, helical twisted roots (e.g. the Wendelkolben pump) or powder ring vacuum pumps.
* '''Reciprocating-type''' positive displacement: piston or diaphragm pumps.
* '''Linear-type''' positive displacement: Rope pump|rope pumps and chain pumps.

===== Rotary Positive Displacement Pumps =====
[[File:220px-Rotary_vane_pump.svg.png|thumb|Rotary vane pump]]
Positive displacement rotary pumps are pumps that move powder using the principles of rotation. The vacuum created by the rotation of the pump captures and draws in the powders.

'''Advantages:''' Rotary pumps are very efficient because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

'''Drawbacks:''' Positive displacement rotary pumps also have their weaknesses. Because of the nature of the pump, the clearance between the rotating pump and the outer edge must be very close, requiring that the pumps rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the powders will cause erosion. Rotary pumps that experience such erosion eventually show signs of enlarged clearances, which allow powder to slip through and reduce the efficiency of the pump.

===== Reciprocating Positive Displacement Pumps =====

Reciprocating-type pumps require a system of suction and discharge valves to ensure that the powder moves in a positive direction. Pumps in this category range from having "simplex" one cylinder, to in some cases "quad" (four) cylinders or more. Most reciprocating-type pumps are "duplex" (two) or "triplex" (three) cylinder. Furthermore, they can be either "single acting" independent suction and discharge strokes or "double acting" suction and discharge in both directions. The pumps can be powered by air, steam or through a belt drive from an engine or motor. This type of pump was used extensively in the early days of steam propulsion (19th century) as boiler feed water pumps. Reciprocating pumps are now typically used for pumping highly viscous powders including concrete and heavy oils, and special applications demanding low flow rates against high resistance.

These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pumps as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

Typical reciprocating pumps are:
* [[Plunger Pumps]] - a reciprocating plunger pushes the powder through one or two open valves, closed by suction on the way back.
* [[Diaphragm Pumps]] - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder.

==== Various Positive Displacement Pumps ====
The positive displacement principle applies in the following types of pumps:

* [[Progressive Cavity Pumps]]
* [[Diaphragm Pumps]]
* [[Screw Pumps]]
* [[Peristaltic Pumps]]

Pumps

2012-03-15T11:07:27Z

Mark:

[[Category:Pumps]]{{Knoppen}}
<noinclude></noinclude>
[[Image:Jet_pump.jpg|thumb||right|A jet pump]]

A '''pump''' displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps.

==Types==
===[[Positive Displacement Pumps]]===
[[Image:Drehkolbenpumpe.jpg|thumb||right|A lobe pump]]
[[Image:423px-Common_Lobe_Pump.png|thumb|right|upright|lobe pump internals]]
[[Image:Two_moving_spirals_scroll_pump.gif|thumb|Mechanism of a scroll pump]]

A positive displacement pump causes a powder to move by trapping a fixed amount of it and then forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps work using an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pump as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

==== Positive Displacement Pump behavior and safety ====
Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, will in theory produce the same flow at a given speed (RPM) no matter what the discharge pressure. Thus, positive displacement pumps are constant flow machines. However due to a slight increase in internal leakage as the pressure increases, a truly constant flow rate cannot be achieved.

A positive displacement pump must not be operated against a closed valve on the discharge side of the pump, because it has no shut-off head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase, until the line bursts or the pump is severely damaged, or both.

A relief or safety valve on the discharge side of the positive displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve should in general only be used as a safety precaution, an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended.

==== Positive Displacement Types ====
[[Image:Lysholm_screw_rotors.jpg|thumb|upright|Screw pump]]
A positive displacement pump can be further classified according to the mechanism used to move the powder:

* '''Rotary-type''' positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, helical twisted roots (e.g. the Wendelkolben pump) or powder ring vacuum pumps.
* '''Reciprocating-type''' positive displacement: piston or diaphragm pumps.
* '''Linear-type''' positive displacement: Rope pump|rope pumps and chain pumps.

===== Rotary Positive Displacement Pumps =====
[[File:220px-Rotary_vane_pump.svg.png|thumb|Rotary vane pump]]
Positive displacement rotary pumps are pumps that move powder using the principles of rotation. The vacuum created by the rotation of the pump captures and draws in the powders.

'''Advantages:''' Rotary pumps are very efficient because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

'''Drawbacks:''' Positive displacement rotary pumps also have their weaknesses. Because of the nature of the pump, the clearance between the rotating pump and the outer edge must be very close, requiring that the pumps rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the powders will cause erosion. Rotary pumps that experience such erosion eventually show signs of enlarged clearances, which allow powder to slip through and reduce the efficiency of the pump.

===== Reciprocating Positive Displacement Pumps =====

Reciprocating-type pumps require a system of suction and discharge valves to ensure that the powder moves in a positive direction. Pumps in this category range from having "simplex" one cylinder, to in some cases "quad" (four) cylinders or more. Most reciprocating-type pumps are "duplex" (two) or "triplex" (three) cylinder. Furthermore, they can be either "single acting" independent suction and discharge strokes or "double acting" suction and discharge in both directions. The pumps can be powered by air, steam or through a belt drive from an engine or motor. This type of pump was used extensively in the early days of steam propulsion (19th century) as boiler feed water pumps. Reciprocating pumps are now typically used for pumping highly viscous powders including concrete and heavy oils, and special applications demanding low flow rates against high resistance.

These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pumps as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

Typical reciprocating pumps are:
* [[Plunger Pumps]] - a reciprocating plunger pushes the powder through one or two open valves, closed by suction on the way back.
* [[Diaphragm Pumps]] - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder.

==== Various Positive Displacement Pumps ====
The positive displacement principle applies in the following types of pumps:

* [[Progressive Cavity Pumps]]
* [[Diaphragm Pumps]]
* [[Screw Pumps]]
* [[Peristaltic Pumps]]

===[[Impulse Pumps]]===
Impulse pumps use pressure created by gas (usually air). In some impulse pumps the gas trapped in the liquid (usually water), is released and accumulated somewhere in the pump, creating a pressure which can push part of the liquid upwards. Impulse pumps include:
* [[Airlift Pumps]] - run on air inserted into pipe, pushing up the water, when bubbles move upward, or on pressure inside pipe pushing water up.

===[[Velocity Pumps]]===
[[Image:Centrifugal 2.png|thumb|right|A centrifugal pump uses a spinning "impeller" which has backward-swept arms]]

[[Rotodynamic Pumps]] (or dynamic pumps) are a type of velocity pump in which kinetic energy is added to the fluid by increasing the flow velocity. This increase in energy is converted to a gain in potential energy (pressure) when the velocity is reduced prior to or as the flow exits the pump into the discharge pipe. This conversion of kinetic energy to pressure can be explained by the First law of thermodynamics or more specifically by Bernoulli's principle.

Dynamic pumps can be further subdivided according to the means in which the velocity gain is achieved.

These types of pumps have a number of characteristics:
# Continuous energy
# Conversion of added energy to increase in kinetic energy (increase in velocity)
# Conversion of increased velocity (kinetic energy) to an increase in pressure head

One practical difference between dynamic and positive displacement pumps is their ability to operate under closed valve conditions. Positive displacement pumps physically displace the fluid; hence closing a valve downstream of a positive displacement pump will result in a continual build up in pressure resulting in mechanical failure of either pipeline or pump. Dynamic pumps differ in that they can be safely operated under closed valve conditions (for short periods of time).

===[[Gravity Pumps]]===

===[[Steam Pumps]]===

===[[Valveless Pumps]]===

Positive Displacement Pumps

2012-03-15T11:07:03Z

Mark:

[[Category:Pumps]]{{Knoppen}}
<noinclude></noinclude>
[[Image:Jet_pump.jpg|thumb||right|A jet pump]]

A '''pump''' displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps.

==Types==
===[[Positive Displacement Pumps]]===
[[Image:Drehkolbenpumpe.jpg|thumb||right|A lobe pump]]
[[Image:423px-Common_Lobe_Pump.png|thumb|right|upright|lobe pump internals]]
[[Image:Two_moving_spirals_scroll_pump.gif|thumb|Mechanism of a scroll pump]]

A positive displacement pump causes a powder to move by trapping a fixed amount of it and then forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps work using an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pump as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

==== Positive Displacement Pump behavior and safety ====
Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, will in theory produce the same flow at a given speed (RPM) no matter what the discharge pressure. Thus, positive displacement pumps are constant flow machines. However due to a slight increase in internal leakage as the pressure increases, a truly constant flow rate cannot be achieved.

A positive displacement pump must not be operated against a closed valve on the discharge side of the pump, because it has no shut-off head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase, until the line bursts or the pump is severely damaged, or both.

A relief or safety valve on the discharge side of the positive displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve should in general only be used as a safety precaution, an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended.

==== Positive Displacement Types ====
[[Image:Lysholm_screw_rotors.jpg|thumb|upright|Screw pump]]
A positive displacement pump can be further classified according to the mechanism used to move the powder:

* '''Rotary-type''' positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, helical twisted roots (e.g. the Wendelkolben pump) or powder ring vacuum pumps.
* '''Reciprocating-type''' positive displacement: piston or diaphragm pumps.
* '''Linear-type''' positive displacement: Rope pump|rope pumps and chain pumps.

===== Rotary Positive Displacement Pumps =====
[[File:220px-Rotary_vane_pump.svg.png|thumb|Rotary vane pump]]
Positive displacement rotary pumps are pumps that move powder using the principles of rotation. The vacuum created by the rotation of the pump captures and draws in the powders.

'''Advantages:''' Rotary pumps are very efficient because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

'''Drawbacks:''' Positive displacement rotary pumps also have their weaknesses. Because of the nature of the pump, the clearance between the rotating pump and the outer edge must be very close, requiring that the pumps rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the powders will cause erosion. Rotary pumps that experience such erosion eventually show signs of enlarged clearances, which allow powder to slip through and reduce the efficiency of the pump.

===== Reciprocating Positive Displacement Pumps =====

Reciprocating-type pumps require a system of suction and discharge valves to ensure that the powder moves in a positive direction. Pumps in this category range from having "simplex" one cylinder, to in some cases "quad" (four) cylinders or more. Most reciprocating-type pumps are "duplex" (two) or "triplex" (three) cylinder. Furthermore, they can be either "single acting" independent suction and discharge strokes or "double acting" suction and discharge in both directions. The pumps can be powered by air, steam or through a belt drive from an engine or motor. This type of pump was used extensively in the early days of steam propulsion (19th century) as boiler feed water pumps. Reciprocating pumps are now typically used for pumping highly viscous powders including concrete and heavy oils, and special applications demanding low flow rates against high resistance.

These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pumps as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

Typical reciprocating pumps are:
* [[Plunger Pumps]] - a reciprocating plunger pushes the powder through one or two open valves, closed by suction on the way back.
* [[Diaphragm Pumps]] - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder.

==== Various Positive Displacement Pumps ====
The positive displacement principle applies in the following types of pumps:

* [[Progressive Cavity Pumps]]
* [[Diaphragm Pumps]]
* [[Screw Pumps]]
* [[Peristaltic Pumps]]

Positive Displacement Pumps

2012-03-15T10:55:51Z

Mark:

[[Category:Pumps]]{{Knoppen}}
<noinclude></noinclude>
[[Image:Jet_pump.jpg|thumb||right|A jet pump]]

A '''pump''' displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps.

==Types==
===[[Positive Displacement Pumps]]===
[[Image:Drehkolbenpumpe.jpg|thumb||right|A lobe pump]]
[[Image:423px-Common_Lobe_Pump.png|thumb|right|upright|lobe pump internals]]
[[Image:Two_moving_spirals_scroll_pump.gif|thumb|Mechanism of a scroll pump]]

A positive displacement pump causes a powder to move by trapping a fixed amount of it and then forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps work using an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pump as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

==== Positive Displacement Pump behavior and safety ====
Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, will in theory produce the same flow at a given speed (RPM) no matter what the discharge pressure. Thus, positive displacement pumps are constant flow machines. However due to a slight increase in internal leakage as the pressure increases, a truly constant flow rate cannot be achieved.

A positive displacement pump must not be operated against a closed valve on the discharge side of the pump, because it has no shut-off head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase, until the line bursts or the pump is severely damaged, or both.

A relief or safety valve on the discharge side of the positive displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve should in general only be used as a safety precaution, an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended.

==== Positive Displacement Types ====
[[Image:Lysholm_screw_rotors.jpg|thumb|upright|Screw pump]]
A positive displacement pump can be further classified according to the mechanism used to move the powder:

* '''Rotary-type''' positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, helical twisted roots (e.g. the Wendelkolben pump) or powder ring vacuum pumps.
* '''Reciprocating-type''' positive displacement: piston or diaphragm pumps.
* '''Linear-type''' positive displacement: Rope pump|rope pumps and chain pumps.

===== Rotary Positive Displacement Pumps =====
[[File:220px-Rotary_vane_pump.svg.png|thumb|Rotary vane pump]]
Positive displacement rotary pumps are pumps that move powder using the principles of rotation. The vacuum created by the rotation of the pump captures and draws in the powders.

'''Advantages:''' Rotary pumps are very efficient because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

'''Drawbacks:''' Positive displacement rotary pumps also have their weaknesses. Because of the nature of the pump, the clearance between the rotating pump and the outer edge must be very close, requiring that the pumps rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the powders will cause erosion. Rotary pumps that experience such erosion eventually show signs of enlarged clearances, which allow powder to slip through and reduce the efficiency of the pump.

Rotary positive displacement pumps can be grouped into three main types:
* [[Gear Pumps]] - a simple type of rotary pump where the powder is pushed between two gears.
* [[Screw Pumps]] - the shape of the internals of this pump usually two screws turning against each other pump the powder.
* [[Rotary Vane Pumps]] - similar to scroll compressors, consisting of a cylindrical rotor encased in a similarly shaped housing. As the rotor turns, the vanes trap powder between the rotor and the casing, drawing the powder through the pump.

===== Reciprocating Positive Displacement Pumps =====

Reciprocating-type pumps require a system of suction and discharge valves to ensure that the powder moves in a positive direction. Pumps in this category range from having "simplex" one cylinder, to in some cases "quad" (four) cylinders or more. Most reciprocating-type pumps are "duplex" (two) or "triplex" (three) cylinder. Furthermore, they can be either "single acting" independent suction and discharge strokes or "double acting" suction and discharge in both directions. The pumps can be powered by air, steam or through a belt drive from an engine or motor. This type of pump was used extensively in the early days of steam propulsion (19th century) as boiler feed water pumps. Reciprocating pumps are now typically used for pumping highly viscous powders including concrete and heavy oils, and special applications demanding low flow rates against high resistance.

These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. powder flows into the pumps as the cavity on the suction side expands and the powder flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

Typical reciprocating pumps are:
* [[Plunger Pumps]] - a reciprocating plunger pushes the powder through one or two open valves, closed by suction on the way back.
* [[Diaphragm Pumps]] - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder.

==== Various Positive Displacement Pumps ====
The positive displacement principle applies in the following types of pumps:
* [[Lobe Pumps]]
* [[Progressive Cavity Pumps]]
* [[Gear Pumps]]
* [[Diaphragm Pumps]]
* [[Screw Pumps]]
* [[Gear Pumps]]
* [[Hydraulic Pumps]]
* [[Vane Pumps]]
* [[Regenerative Pumps]]
* [[Peristaltic Pumps]]
* [[Rope Pumps]]

Pumps

2012-03-15T10:46:43Z

Mark:

[[Category:Pumps]]{{Knoppen}}
<noinclude></noinclude>
[[Image:Jet_pump.jpg|thumb||right|A jet pump]]

A '''pump''' displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps.

==Types==
===[[Positive Displacement Pumps]]===
[[Image:Drehkolbenpumpe.jpg|thumb||right|A lobe pump]]
[[Image:423px-Common_Lobe_Pump.png|thumb|right|upright|lobe pump internals]]
[[Image:Two_moving_spirals_scroll_pump.gif|thumb|Mechanism of a scroll pump]]

A positive displacement pump uses pressure`s to move by trapping a fixed amount of it and then forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps work using an expanding cavity on the suction side and a decreasing cavity on the discharge side. powders flow into the pump as the cavity on the suction side expands and the powders flow out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

==== Positive Displacement Pump behavior and safety ====
Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, will in theory produce the same flow at a given speed (RPM) no matter what the discharge pressure. Thus, positive displacement pumps are constant flow machines. However due to a slight increase in internal leakage as the pressure increases, a truly constant flow rate cannot be achieved.

A positive displacement pump must not be operated against a closed valve on the discharge side of the pump, because it has no shut-off head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase, until the line bursts or the pump is severely damaged, or both.

A relief or safety valve on the discharge side of the positive displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve should in general only be used as a safety precaution, an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended.

==== Positive Displacement Types ====
[[Image:Lysholm_screw_rotors.jpg|thumb|upright|Screw pump]]
A positive displacement pump can be further classified according to the mechanism used to move the powder:

* '''Rotary-type''' positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, helical twisted roots
* '''Reciprocating-type''' positive displacement: piston or diaphragm pumps.
* '''Linear-type''' positive displacement: Rope pump|rope pumps and chain pumps.

===== Rotary Positive Displacement Pumps =====
[[File:220px-Rotary_vane_pump.svg.png|thumb|Rotary vane pump]]
Positive displacement rotary pumps are pumps that move fluid using the principles of rotation. The vacuum created by the rotation of the pump captures and draws in the liquid.

'''Advantages:''' Rotary pumps are very efficient because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

'''Drawbacks:''' Positive displacement rotary pumps also have their weaknesses. Because of the nature of the pump, the clearance between the rotating pump and the outer edge must be very close, requiring that the pumps rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the powders will cause erosion.

Rotary positive displacement pumps can be grouped into three main types:
* [[Gear Pumps]] - a simple type of rotary pump where the powder is pushed between two gears.
* [[Screw Pumps]] - the shape of the internals of this pump usually two screws turning against each other pump the powders.
* [[Rotary Vane Pumps]] - similar to scroll compressors, consisting of a cylindrical rotor encased in a similarly shaped housing. As the rotor turns, the vanes trap fluid between the rotor and the casing, drawing the powder through the pump.

===== Reciprocating Positive Displacement Pumps =====

Reciprocating-type pumps require a system of suction and discharge valves to ensure that the powder moves in a positive direction. Pumps in this category range from having "simplex" one cylinder, to in some cases "quad" (four) cylinders or more. Most reciprocating-type pumps are "duplex" (two) or "triplex" (three) cylinder. Furthermore, they can be either "single acting" independent suction and discharge strokes or "double acting" suction and discharge in both directions. The pumps can be powered by air, steam or through a belt drive from an engine or motor. This type of pump was used extensively in the early days of steam propulsion (19th century) as boiler feed water pumps.

These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. powders flow into the pumps as the cavity on the suction side expands and the powders flow out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

Typical reciprocating pumps are:
* [[Plunger Pumps]] - a reciprocating plunger pushes the powder through one or two open valves, closed by suction on the way back.
* [[Diaphragm Pumps]] - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder.

==== Various Positive Displacement Pumps ====
The positive displacement principle applies in the following types of pumps:
* [[Lobe Pumps]]
* [[Progressive Cavity Pumps]]
* [[Gear Pumps]]
* [[Diaphragm Pumps]]
* [[Screw Pumps]]
* [[Gear Pumps]]
* [[Hydraulic Pumps]]
* [[Vane Pumps]]
* [[Regenerative Pumps]]
* [[Peristaltic Pumps]]
* [[Rope Pumps]]

===[[Impulse Pumps]]===
Impulse pumps use pressure created by gas (usually air). In some impulse pumps the gas trapped in the liquid (usually water), is released and accumulated somewhere in the pump, creating a pressure which can push part of the liquid upwards. Impulse pumps include:
* [[Airlift Pumps]] - run on air inserted into pipe, pushing up the water, when bubbles move upward, or on pressure inside pipe pushing water up.

===[[Velocity Pumps]]===
[[Image:Centrifugal 2.png|thumb|right|A centrifugal pump uses a spinning "impeller" which has backward-swept arms]]

[[Rotodynamic Pumps]] (or dynamic pumps) are a type of velocity pump in which kinetic energy is added to the fluid by increasing the flow velocity. This increase in energy is converted to a gain in potential energy (pressure) when the velocity is reduced prior to or as the flow exits the pump into the discharge pipe. This conversion of kinetic energy to pressure can be explained by the First law of thermodynamics or more specifically by Bernoulli's principle.

Dynamic pumps can be further subdivided according to the means in which the velocity gain is achieved.

These types of pumps have a number of characteristics:
# Continuous energy
# Conversion of added energy to increase in kinetic energy (increase in velocity)
# Conversion of increased velocity (kinetic energy) to an increase in pressure head

One practical difference between dynamic and positive displacement pumps is their ability to operate under closed valve conditions. Positive displacement pumps physically displace the fluid; hence closing a valve downstream of a positive displacement pump will result in a continual build up in pressure resulting in mechanical failure of either pipeline or pump. Dynamic pumps differ in that they can be safely operated under closed valve conditions (for short periods of time).

===[[Gravity Pumps]]===

===[[Steam Pumps]]===

===[[Valveless Pumps]]===

Pumps

2012-03-15T10:44:57Z

Mark:

[[Category:Pumps]]{{Knoppen}}
<noinclude></noinclude>
[[Image:Jet_pump.jpg|thumb||right|A jet pump]]

A '''pump''' displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps.

==Types==
===[[Positive Displacement Pumps]]===
[[Image:Drehkolbenpumpe.jpg|thumb||right|A lobe pump]]
[[Image:423px-Common_Lobe_Pump.png|thumb|right|upright|lobe pump internals]]
[[Image:Two_moving_spirals_scroll_pump.gif|thumb|Mechanism of a scroll pump]]

A positive displacement pump uses pressure`s to move by trapping a fixed amount of it and then forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps work using an expanding cavity on the suction side and a decreasing cavity on the discharge side. powders flow into the pump as the cavity on the suction side expands and the powders flow out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

==== Positive Displacement Pump behavior and safety ====
Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, will in theory produce the same flow at a given speed (RPM) no matter what the discharge pressure. Thus, positive displacement pumps are constant flow machines. However due to a slight increase in internal leakage as the pressure increases, a truly constant flow rate cannot be achieved.

A positive displacement pump must not be operated against a closed valve on the discharge side of the pump, because it has no shut-off head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase, until the line bursts or the pump is severely damaged, or both.

A relief or safety valve on the discharge side of the positive displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve should in general only be used as a safety precaution, an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended.

==== Positive Displacement Types ====
[[Image:Lysholm_screw_rotors.jpg|thumb|upright|Screw pump]]
A positive displacement pump can be further classified according to the mechanism used to move the powder:

* '''Rotary-type''' positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, helical twisted roots
* '''Reciprocating-type''' positive displacement: piston or diaphragm pumps.
* '''Linear-type''' positive displacement: Rope pump|rope pumps and chain pumps.

===== Rotary Positive Displacement Pumps =====
[[File:220px-Rotary_vane_pump.svg.png|thumb|Rotary vane pump]]
Positive displacement rotary pumps are pumps that move fluid using the principles of rotation. The vacuum created by the rotation of the pump captures and draws in the liquid.

'''Advantages:''' Rotary pumps are very efficient because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

'''Drawbacks:''' Positive displacement rotary pumps also have their weaknesses. Because of the nature of the pump, the clearance between the rotating pump and the outer edge must be very close, requiring that the pumps rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the powders will cause erosion.

Rotary positive displacement pumps can be grouped into three main types:
* [[Gear Pumps]] - a simple type of rotary pump where the powder is pushed between two gears.
* [[Screw Pumps]] - the shape of the internals of this pump usually two screws turning against each other pump the powders.
* [[Rotary Vane Pumps]] - similar to scroll compressors, consisting of a cylindrical rotor encased in a similarly shaped housing. As the rotor turns, the vanes trap fluid between the rotor and the casing, drawing the powder through the pump.

===== Reciprocating Positive Displacement Pumps =====

Reciprocating-type pumps require a system of suction and discharge valves to ensure that the powder moves in a positive direction. Pumps in this category range from having "simplex" one cylinder, to in some cases "quad" (four) cylinders or more. Most reciprocating-type pumps are "duplex" (two) or "triplex" (three) cylinder. Furthermore, they can be either "single acting" independent suction and discharge strokes or "double acting" suction and discharge in both directions. The pumps can be powered by air, steam or through a belt drive from an engine or motor. This type of pump was used extensively in the early days of steam propulsion (19th century) as boiler feed water pumps.

These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. powders flow into the pumps as the cavity on the suction side expands and the powders flow out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

Typical reciprocating pumps are:
* [[Plunger Pumps]] - a reciprocating plunger pushes the powder through one or two open valves, closed by suction on the way back.
* [[Diaphragm Pumps]] - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder.

==== Various Positive Displacement Pumps ====
The positive displacement principle applies in the following types of pumps:
* [[Lobe Pumps]]
* [[Progressive Cavity Pumps]]
* [[Gear Pumps]]
* [[Diaphragm Pumps]]
* [[Screw Pumps]]
* [[Gear Pumps]]
* [[Hydraulic Pumps]]
* [[Vane Pumps]]
* [[Regenerative Pumps]]
* [[Peristaltic Pumps]]
* [[Rope Pumps]]

===[[Impulse Pumps]]===
[[File:pulser pump.jpg|thumb|The pulser pump]]
Impulse pumps use pressure created by gas (usually air). In some impulse pumps the gas trapped in the liquid (usually water), is released and accumulated somewhere in the pump, creating a pressure which can push part of the liquid upwards. Impulse pumps include:
* [[Hydraulic Ram Pumps]] - uses pressure built up internally from released gas in liquid flow. (see below)
* [[Airlift Pumps]] - run on air inserted into pipe, pushing up the water, when bubbles move upward, or on pressure inside pipe pushing water up.

===[[Velocity Pumps]]===
[[Image:Centrifugal 2.png|thumb|right|A centrifugal pump uses a spinning "impeller" which has backward-swept arms]]

[[Rotodynamic Pumps]] (or dynamic pumps) are a type of velocity pump in which kinetic energy is added to the fluid by increasing the flow velocity. This increase in energy is converted to a gain in potential energy (pressure) when the velocity is reduced prior to or as the flow exits the pump into the discharge pipe. This conversion of kinetic energy to pressure can be explained by the First law of thermodynamics or more specifically by Bernoulli's principle.

Dynamic pumps can be further subdivided according to the means in which the velocity gain is achieved.

These types of pumps have a number of characteristics:
# Continuous energy
# Conversion of added energy to increase in kinetic energy (increase in velocity)
# Conversion of increased velocity (kinetic energy) to an increase in pressure head

One practical difference between dynamic and positive displacement pumps is their ability to operate under closed valve conditions. Positive displacement pumps physically displace the fluid; hence closing a valve downstream of a positive displacement pump will result in a continual build up in pressure resulting in mechanical failure of either pipeline or pump. Dynamic pumps differ in that they can be safely operated under closed valve conditions (for short periods of time).

===[[Gravity Pumps]]===

===[[Steam Pumps]]===

===[[Valveless Pumps]]===

Pumps

2012-03-15T10:43:38Z

Mark:

[[Category:Pumps]]{{Knoppen}}
<noinclude></noinclude>
[[Image:Jet_pump.jpg|thumb||right|A jet pump]]

A '''pump''' displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps.

==Types==
===[[Positive Displacement Pumps]]===
[[Image:Drehkolbenpumpe.jpg|thumb||right|A lobe pump]]
[[Image:423px-Common_Lobe_Pump.png|thumb|right|upright|lobe pump internals]]
[[Image:Two_moving_spirals_scroll_pump.gif|thumb|Mechanism of a scroll pump]]

A positive displacement pump uses pressure`s to move by trapping a fixed amount of it and then forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps work using an expanding cavity on the suction side and a decreasing cavity on the discharge side. powders flow into the pump as the cavity on the suction side expands and the powders flow out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

==== Positive Displacement Pump behavior and safety ====
Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, will in theory produce the same flow at a given speed (RPM) no matter what the discharge pressure. Thus, positive displacement pumps are constant flow machines. However due to a slight increase in internal leakage as the pressure increases, a truly constant flow rate cannot be achieved.

A positive displacement pump must not be operated against a closed valve on the discharge side of the pump, because it has no shut-off head like centrifugal pumps. A positive displacement pump operating against a closed discharge valve will continue to produce flow and the pressure in the discharge line will increase, until the line bursts or the pump is severely damaged, or both.

A relief or safety valve on the discharge side of the positive displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve should in general only be used as a safety precaution, an external relief valve installed in the discharge line with a return line back to the suction line or supply tank is recommended.

==== Positive Displacement Types ====
[[Image:Lysholm_screw_rotors.jpg|thumb|upright|Screw pump]]
A positive displacement pump can be further classified according to the mechanism used to move the powder:

* '''Rotary-type''' positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, helical twisted roots
* '''Reciprocating-type''' positive displacement: piston or diaphragm pumps.
* '''Linear-type''' positive displacement: Rope pump|rope pumps and chain pumps.

===== Rotary Positive Displacement Pumps =====
[[File:220px-Rotary_vane_pump.svg.png|thumb|Rotary vane pump]]
Positive displacement rotary pumps are pumps that move fluid using the principles of rotation. The vacuum created by the rotation of the pump captures and draws in the liquid.

'''Advantages:''' Rotary pumps are very efficient because they naturally remove air from the lines, eliminating the need to bleed the air from the lines manually.

'''Drawbacks:''' Positive displacement rotary pumps also have their weaknesses. Because of the nature of the pump, the clearance between the rotating pump and the outer edge must be very close, requiring that the pumps rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the powders will cause erosion.

Rotary positive displacement pumps can be grouped into three main types:
* [[Gear Pumps]] - a simple type of rotary pump where the powder is pushed between two gears.
* [[Screw Pumps]] - the shape of the internals of this pump usually two screws turning against each other pump the powders.
* [[Rotary Vane Pumps]] - similar to scroll compressors, consisting of a cylindrical rotor encased in a similarly shaped housing. As the rotor turns, the vanes trap fluid between the rotor and the casing, drawing the powder through the pump.

===== Reciprocating Positive Displacement Pumps =====

Reciprocating-type pumps require a system of suction and discharge valves to ensure that the powder moves in a positive direction. Pumps in this category range from having "simplex" one cylinder, to in some cases "quad" (four) cylinders or more. Most reciprocating-type pumps are "duplex" (two) or "triplex" (three) cylinder. Furthermore, they can be either "single acting" independent suction and discharge strokes or "double acting" suction and discharge in both directions. The pumps can be powered by air, steam or through a belt drive from an engine or motor. This type of pump was used extensively in the early days of steam propulsion (19th century) as boiler feed water pumps.

These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. powders flow into the pumps as the cavity on the suction side expands and the powders flow out of the discharge as the cavity collapses. The volume is constant given each cycle of operation.

Typical reciprocating pumps are:
* [[Plunger Pumps]] - a reciprocating plunger pushes the powder through one or two open valves, closed by suction on the way back.
* [[Diaphragm Pumps]] - similar to plunger pumps, where the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder.

==== Various Positive Displacement Pumps ====
The positive displacement principle applies in the following types of pumps:
* [[Lobe Pumps]]
* [[Progressive Cavity Pumps]]
* [[Gear Pumps]]
* [[Diaphragm Pumps]]
* [[Screw Pumps]]
* [[Gear Pumps]]
* [[Hydraulic Pumps]]
* [[Vane Pumps]]
* [[Regenerative Pumps]]
* [[Peristaltic Pumps]]
* [[Rope Pumps]]

===[[Impulse Pumps]]===
[[File:pulser pump.jpg|thumb|The pulser pump]]
Impulse pumps use pressure created by gas (usually air). In some impulse pumps the gas trapped in the liquid (usually water), is released and accumulated somewhere in the pump, creating a pressure which can push part of the liquid upwards. Impulse pumps include:
* [[Hydraulic ram pumps]] - uses pressure built up internally from released gas in liquid flow. (see below)
* [[Pulser pump]]s - run with natural resources, by kinetic energy only.
* [[Airlift pump]]s - run on air inserted into pipe, pushing up the water, when bubbles move upward, or on pressure inside pipe pushing water up.

===[[Velocity Pumps]]===
[[Image:Centrifugal 2.png|thumb|right|A centrifugal pump uses a spinning "impeller" which has backward-swept arms]]

[[Rotodynamic Pumps]] (or dynamic pumps) are a type of velocity pump in which kinetic energy is added to the fluid by increasing the flow velocity. This increase in energy is converted to a gain in potential energy (pressure) when the velocity is reduced prior to or as the flow exits the pump into the discharge pipe. This conversion of kinetic energy to pressure can be explained by the First law of thermodynamics or more specifically by Bernoulli's principle.

Dynamic pumps can be further subdivided according to the means in which the velocity gain is achieved.

These types of pumps have a number of characteristics:
# Continuous energy
# Conversion of added energy to increase in kinetic energy (increase in velocity)
# Conversion of increased velocity (kinetic energy) to an increase in pressure head

One practical difference between dynamic and positive displacement pumps is their ability to operate under closed valve conditions. Positive displacement pumps physically displace the fluid; hence closing a valve downstream of a positive displacement pump will result in a continual build up in pressure resulting in mechanical failure of either pipeline or pump. Dynamic pumps differ in that they can be safely operated under closed valve conditions (for short periods of time).

===[[Gravity Pumps]]===

===[[Steam Pumps]]===

===[[Valveless Pumps]]===

Membrane Pumps

2012-03-15T10:22:42Z

Mark:

Diaphragm Pumps

2012-03-15T10:21:20Z

Mark:

File:Bomba diafragma.jpg

2012-03-15T10:19:50Z

Mark:

File:Membrane pump on oil tanker deck.jpg

2012-03-15T10:19:34Z

Mark:

File:DiaphragmPump.gif

2012-03-15T10:19:20Z

Mark:

Screw Pumps

2012-03-15T10:13:06Z

Mark:

File:Screw pump1.gif

2012-03-15T10:12:34Z

Mark: