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. 702-6898
BrandRS PRO
SGD111.66
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. 702-6894
BrandRS PRO
SGD75.89
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. 667-9107
Mfr. Part No.CW474-024
BrandXylem
SGD403.20
Each
units
Diaphragm Electric 13L/min - 3 bar 1/2 in Hose Barb 1/2 in Hose Barb IP55 CW474 - Glass Fibre Reinforced PP 230 V ac 120W -
RS Stock No. 121-8592
Mfr. Part No.GMXa0708PVT20000U11130EN
BrandProMinent
SGD2,457.98
Each
units
- Electric 7.6L/h - 7 bar 3/4 in G 3/4 in G IP65 GMXa +20°C PVDF 100 to 230 V 24 / 30 (Consumption)W PVDF
RS Stock No. 705-9333
Mfr. Part No.R3711132A
SGD258.88
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. 705-9359
Mfr. Part No.R3521339A
SGD345.43
Each
units
Diaphragm Electric 7.6L/min 41m 4.1 bar 3/4 in NPT 3/8 in NPT - R352 +60°C PP 24 V 144W -
RS Stock No. 667-9104
Mfr. Part No.D3135H7011AR
SGD294.27
Each
units
Diaphragm Electric 8.1L/min 30m 7.1 bar 3/8 in NPT 3/8 in NPT IP44 D3135 - Glass Fibre Reinforced PP 12 V - -
RS Stock No. 705-9324
Mfr. Part No.RLFP122201D
SGD168.89
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. 667-9100
Mfr. Part No.D3131H5011AR
SGD284.55
Each
units
Diaphragm Electric 5.3L/min 30m 4.2 bar 3/8 in NPT 3/8 in NPT IP44 D3131 +54°C Glass Filled PP 12 V dc - -
RS Stock No. 667-9093
Mfr. Part No.R4300143A
SGD349.48
Each
units
Diaphragm Electric 19L/min - 3.1 bar 3/4 in Hose Barb 3/4 in Hose Barb IP44 R4300 - PP 12 V dc - Buna, Elastomer, PP
RS Stock No. 446-3506
Mfr. Part No.416990
SGD724.55
Each
units
Diaphragm Electric 10.8L/min 28m 15 bar 1/2 in NPT 1/2 in NPT IP44 AD550 +60°C - 230 V 33W -
RS Stock No. 705-9330
Mfr. Part No.RLFP222202D
SGD158.65
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. 705-9343
Mfr. Part No.R3811342A
SGD301.86
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. 446-3483
Mfr. Part No.416989
SGD409.22
Each
units
Diaphragm Electric 3L/min 89m 20 bar - - IP44 AD4/90 +77°C - 230 V 55W -
RS Stock No. 705-9349
Mfr. Part No.R3811142A
SGD296.62
Each
units
Diaphragm Electric 5.5L/min 105m 10.5 bar 3/8 in NPT 3/8 in NPT - R381 +60°C Glass Fibre Reinforced Nylon 12 V 108W -
RS Stock No. 705-9355
Mfr. Part No.R3521139A
SGD322.41
Each
units
Diaphragm Electric 15.1L/min 41m 4.1 bar 1/2 in Hose Barb 1/2 in Hose Barb IP54 R352 +60°C PP 12 V 108W -
RS Stock No. 667-9097
Mfr. Part No.R4300242A
SGD453.36
Each
units
Diaphragm Electric 12L/min 40m 2.1 bar 1/2 in Hose Barb 1/2 in Hose Barb IP44 R4300 +54°C Glass Fibre Reinforced PP 230 V ac - -
RS Stock No. 705-9327
Mfr. Part No.RLF222201D
SGD151.23
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. 667-9194
Mfr. Part No.TEP50PTWD
BrandTecnomatic
SGD1,081.66
Each
units
Diaphragm Air 53L/min 70m - 1/2 in G 1/2 in G - TE53-PTW - PP - - -
RS Stock No. 667-9113
Mfr. Part No.G573215A
SGD473.38
Each
units
Diaphragm Air 19L/min - 6.9 bar 1/2 in Hose Barb, 1/4 in Hose Barb 1/2 in Hose Barb, 1/4 in Hose Barb - G5732 +48.9°C PP - - Hastelloy C, Kalrez, PP, Santoprene, Viton
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