what is PDSP Sanitary Self-Priming Double Screw Pump for?
The PDSP Sanitary Self-Priming Double Screw Pump has been produced specifically for hygienic and sanitary applications within the food, chemical and pharmaceutical industries. The pump is entirely machined from cast Stainless Steel AISI 316L with a surface roughness of <0.8 as standard (<0.5 on request) to provide increased corrosion resistance. Competitors units employ a cast iron gear box with epoxy paint which can become eroded over time and need replacing/repairing. The pump shafts are constructed from Duplex Stainless Steel 1.4462 to provide extra rigidity in operation and the pump can be fitted with a number of different sealing options and elastomer materials to suit almost any application.
The Double or Twin Screw Pump design is a combination of all the best advantages of Lobe, Peristaltic, Centrifugal & Circumferential Piston Pumps. The result is an incredibly versatile and robust pump which can be used for a plethora or even a combination of applications within enumerative industries. Below is a table demonstrating this:
|Pump type||Hygienic||Suction Capability||Pressure||Dry running||Gentle handling soft solids||Ease of Maintenance||Handling of Shear Sensitive Fluids||CIP capability|
|PDSP Double Screw Pump||+++||+++||+++||++||++||+++||++||+++|
The Double or Twin Screw Pump is a Rotary Positive Displacement Pump. Its operation is based on the counter rotation of 2 screws or rotors in the pump casing. Both screws are mounted onto their own shafts which are supported by bearing cartridges mounted directly onto the pump casing. One of the pump shafts is externally driven and an internal gear assembly drives the other shaft in the opposing direction. The screws rotate synchronously in opposing directions without touching.
When the screws rotate and pass the suction port the volume between them increases and creates a vacuum which causes liquid to enter the suction port and the pump casing. During the rotation of the screws the fixed amount of fluid is conveyed through the pump. As the screws approach the discharge port the volume between them decreases which creates a pressure build-up, causing the fluid to flow out of the discharge port.
- Speed range from 100 – 3600 rpm
- Fully EHEDG Compliant
- Pulsation free pumping of both thin and highly viscous fluids from 0.5 – 1’000’000 cPs
- Large Free Passage of Solids up to 60 mm in diameter
- Dry Run
- Self-Priming up to 8 m
- Reversible (8 Bar Max Discharge Pressure as standard, if up to 16 bar, bearing arrangement needs to be adjusted)
- Accurate flow control from 0.07 – 0.46 l/rev
- Discharge Pressures up to 16 Bar
- Variable fluid temperatures up to 140ºC
- Low NPSHr requirements, <2 m
- CIP / SIP friendly – minimal dead spaces
- Suitable for Shear Sensitive Fluids
- Suitable for pumping fragile solids
- Can be used for CIP feeding as well as product pumping – No need for a separate Centrifugal Pump for CIP.
- Wide variety of connection types
- Optional Heating & Cooling Jackets
- Optional large pitch screws for increased capacity and solids passage
|Free passage (mm)||20||40||30||60|
|Liters per revolution||0,07||0,14||0,23||0,46|
- Process pump and CIP-pump
- Loading, un-loading and displacement
- CIP (Cleaning in Place) and SIP (Sterilisation in Place)
- Product displacement
|Max Capacity||95 m³/hr|
|Max Pressure||16 Bar|
|Max Viscosity||1’000’000 cPs|
|Max Solids Passage||60 mm – Model & Screw Type Specific|
|Connections||2” – 5” (DN50 – 125)|
|Connection Types||Hygienic Threads DIN 11851, DIN11864-1& 2, SMS 1145
Flanges acc. To EN1092
Tri-Clamp: ISO 2852 & DIN 32676
BSP & NPT Threaded
|Shaft Sealing||Single, double quench/flush or Lip Seal|
|Sealing Materials||SiC / SiC or Tungsten / Tungsten|
|Elastomer Materials||EPDM, Viton, NBR, Teflon, KALREZ, e.g.
according to FDA
|Wetted Parts||AISI 316L (AISI 316L Mo+Ni or Hastelloy CX2MW N26022 upon request)|
|Surface Roughness||<0.8 Micron (Std.), <0.5 upon request (Mechanical & Electro-Polished)|
|Hardening||Hard Inchromizing & Plasma Nitriding (Optional)|
|Drives||Standard: IEC, IE2, B3/B5, IP55, isol cl. F, PTC
Optional: IE3, ATEX, noise reduction
|Data||PDSP 2||PDSP 3||PDSP 4 (Coming Soon!)|
|Max Differential Pressure||16 Bar||16 Bar||16|
|Max Flow||40||95 m³/hr||140|
|Max Speed||3600 rpm||3600 rpm||3600|
|Max Viscosity||1’000’000 cPs||1’000’000 cPs||1’000’000 cPs|
|Free Passage||20 mm||30 mm||40 mm|
|NPSHr||<2 m||<2 m||<2 m|
Single Mechanical Seal
Double Mechanical Seal
The following Mechanical Seal variants are available:
- Single Mechanical Seal: EHP-PDSP
- Single Mechanical Seal with Quench or Flush: EHP-PDSP and Lip seal to 16 Bar
- Double Mechanical Seal: PP-PDSP
- Double Mechanical Seal with Quench or Flush: PP-PDSP and PA-PDSP to 16 Bar
For low pressure quenches the flushing system must have a capacity of 0.25 l/min @ 0.5 mwc.
For pressurised flushes the pressure must be 2 bar higher than the system pressure.