Positive Displacement Pumps

Positive displacement pumps are speciality pumps that provide an approximate constant flow of fluid at the fixed speed. Pump trap a fixed amount of the fluid and then force it into a discharge pipe. Positive displacement pumps can produce the same flow at a given speed (RPM) no matter what the discharge pressure is. These type of pumps cannot operate against the closed valve because they have no shutoff head like centrifugal pumps. Positive displacement pumps constantly produce flow and the pressure built within the blocked line will damage the line, pump or both.
The positive displacement pumps can be divided into two main categories:
A. Rotary pumps are very efficient because they can operate even with highly viscous fluids but require a slow steady speed rotation. If the mechanism rotation is too fast, the fluid can cause erosion, which eventually causes enlarged clearances that liquid can pass through and reduce pressure.
Rotary pumps can be divided into three main types:
• Gear pumps: the simplest pump type that pumps liquid using 2 gears.
• Screw pumps: more complicated pump type where the two screws are positioned against each other to pump the liquid.
• Rotary vane pumps: these pumps have a cylindrical rotary engine. As the rotor circulates, vans trap fluid between the rotor and the engine housing, pushing the liquid through the pump.

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Description Price Pump Type Drive Type Maximum Flow Rate Maximum Head Maximum Working Pressure Input Connection Output Connection IP Rating Series Maximum Fluid Temperature Body Material Supply Voltage Input Power Wetted Materials
RS Stock No. 702-6894
BrandRS PRO
£42.08
Each
Units
Diaphragm Electric 150ml/min - 1 bar - - IP50 D200 +100°C Nylon 1.5 → 4.5 V 0.48W Nitrile, Nylon, Silicone
RS Stock No. 702-6898
BrandRS PRO
£55.72
Each
Units
Diaphragm Electric 380ml/min - 11 psi - - IP50 D250 +100°C Aluminium 1.5 → 5 V 0.48W Anodized Aluminium, Nitrile, Silicone, Stainless Steel
RS Stock No. 705-9327
Mfr. Part No.RLF222201D
£89.38
Each
Units
Diaphragm Electric 3.8L/min 21m 2.5 bar 3/8 in Hose Barb 3/8 in Hose Barb - RLF222 +43°C PP 24 V dc 30W -
RS Stock No. 705-9321
Mfr. Part No.RLFP122202D
£74.06
Each
Units
Diaphragm Electric 3.8L/min 21m 2.5 bar 3/8 in Hose Barb 3/8 in Hose Barb - RLF122 +43°C PP 12 V dc 30W EPDM, PP, Santoprene, Stainless Steel, Viton
RS Stock No. 667-9194
Mfr. Part No.TEP50PTWD
BrandTecnomatic
£651.91
Each
Units
Diaphragm Air 53L/min 70m - 1/2 in G 1/2 in G - TE53-PTW - PP - - -
RS Stock No. 705-6687
Mfr. Part No.AU R2550015 RS1
BrandVerderflex
£163.74
Each
Units
Peristaltic Electric 0.03L/min 10m 1 bar - - - R2550 +40°C ABS, PC 12 V dc 6VA -
RS Stock No. 705-6671
Mfr. Part No.AU R2550120 RS1
BrandVerderflex
£161.32
Each
Units
Peristaltic Electric 0.24L/min 10m 1 bar - - - R2550 +40°C ABS, PC 12 V dc 6VA -
RS Stock No. 705-9330
Mfr. Part No.RLFP222202D
£79.17
Each
Units
Diaphragm Electric 3.8L/min 25m 2.4 bar 3/8 in Hose Barb 3/8 in Hose Barb - RLF222 +43°C PP 24 V dc 30W -
RS Stock No. 493-1920
Mfr. Part No.7043 RS
£232.52
Each
Units
Drum Electric 40L/min 12m - - 3/4 in Plain - - - - 12 V dc - -
RS Stock No. 667-9116
Mfr. Part No.G575215A
£158.56
Each
Units
Diaphragm Air 19L/min - 8.27 bar 1/2 in Hose Barb, 1/4 in Hose Barb 1/2 in Hose Barb, 1/4 in Hose Barb - G5752 - PP - - Hastelloy C, Kalrez, PP, Santoprene, Viton
RS Stock No. 705-9343
Mfr. Part No.R3811342A
£150.43
Each
Units
Diaphragm Electric 5.3L/min 105m 10.5 bar 3/8 in NPT 3/8 in NPT - R381 +60°C Glass Fibre Reinforced Nylon 24 V 108W -
RS Stock No. 705-6656
Mfr. Part No.AU EZ3R16
BrandVerderflex
£97.76
Each
Units
Peristaltic Electric - 20m 1 bar - - - EZ3R1 +40°C Polyamide - 20W -
RS Stock No. 446-3483
Mfr. Part No.416989
£277.12
Each
Units
Diaphragm Electric 3L/min 89m 20 bar - - IP44 AD +77°C - 230 V 55W -
RS Stock No. 121-8586
Mfr. Part No.BT4B1601PVT2000U1110000
BrandProMinent
£810.35
Each
Units
- Electric 1.1L/h - 16 bar 3/4 in G 3/4 in G IP65 BT4B +20°C PVDF 100 to 230 V 9.6 (Consumption)W PVDF
RS Stock No. 705-6659
Mfr. Part No.AU ES3R16
BrandVerderflex
£97.76
Each
Units
Peristaltic Electric - 20m 1 bar - - - ES3R1 +40°C Polyamide - 20W -
RS Stock No. 705-9333
Mfr. Part No.R3711132A
£128.07
Each
Units
Diaphragm Electric 5.5L/min 69m 6.9 bar 3/8 in BSP 3/8 in BSP - R371 +60°C Glass Fibre Reinforced Nylon 12 V dc 108W -
RS Stock No. 446-3506
Mfr. Part No.416990
£361.57
Each
Units
Diaphragm Electric 10.8L/min 28m 15 bar 1/2 in NPT 1/2 in NPT IP44 AD +60°C - 230 V 33W -
RS Stock No. 705-9383
Mfr. Part No.53041-2003-230
£511.66
Each
Units
Impeller Electric 35L/min 16m - 1 in BSP 1 in BSP IP54 - - Bronze 230 V 300W -
RS Stock No. 144-844
Mfr. Part No.BL 5/D
£164.76
Each
Units
Diaphragm Electric 5L/h - 101.5 psi - - IP65 BL5/D - Glass Fibre Reinforced PP 220 V, 240 V 200W -
RS Stock No. 122-6648
Mfr. Part No.TEP50-ANB-D
BrandTecnomatic
£641.84
Each
Units
Diaphragm Air 50L/min 8m - - - - TEP50 - Aluminium - - Aluminium Body, NBR Diaphragms, NBR Valve Balls
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