Wilden® PS4 – 1-1/2" / 38 mm Saniflo™ Hygienic™ HS Air-Operated Double-Diaphragm (AODD) Original™ Series Metal Pump

The Wilden® PS4 – 1-1/2" / 38 mm Original™ Series Saniflo™ Hygienic™ HS model clamped metal Air-Operated Double-Diaphragm (AODD) Pump meets the strict hygienic and sanitary requirements for the food-processing and biopharmaceutical process industries. The PS4 Saniflo Hygienic pump complies with all EHEDG, 3-A, CE, ATEX, USP Class VI, 1935/2004/EC and FDA CFR 21.177 requirements.

The PS4 Saniflo Hygienic pump ensures reliability and ease of use and maintenance by offering CIP (clean in place) and COP (clean out of place) capabilities.

With simple installation and robust durability, the PS4 Saniflo Hygienic pump incorporates a straight flow-through design, large solids passage, shear-sensitive operation, Tri-clamp®-style fittings and efficiencies to ensure process success.

The wetted path material is 316L stainless steel with an Ra 0.8 μm (31.5 μin) interior polish for ease of cleaning.

The Wilden PS4 comes equipped with the Pro-Flo® SHIFT Air Distribution System (ADS) that provides 60% savings in air consumption, more yield per SCFM, precisely metered air consumption for less product waste and maximum Mean Time Between Repair (MTBR). Available Pro-Flo SHIFT center section materials are nickel-plated aluminum and stainless steel.

Elastomers are available in the following materials:

  • Buna-N
  • EPDM
  • PTFE
  • Saniflex
  • Wil-Flex

Features & Benefits

Benefits and Features

The Successful Solution

  • Higher flow rates/increased pump output
  • Intrinsically safe
  • Multiple sanitary elastomers available
  • Superior product containment
  • Clamped connections for faster maintenance
  • Variable flow and pressure
  • Delicate/shear-sensitive
  • Self-priming/dry-priming
  • Dry-run capable
  • Portable and submersible
  • Viscous and non-viscous product transfer
  • Large solids passage
  • Low water requirements
  • Offset valve housing for easy alignment
  • Ease of operation and maintenance


  • Longest Mean Time Between Repair (MTBR)
  • No damage when run dry
  • Deadhead without damage
  • Lube-free operation
  • Increased On/Off reliability


  • Greater flow per SCFM input
  • Reduced air consumption and kilowatt usage
  • Lower operational costs and downtime
  • Optimized applications




(Water Chambers and Manifolds)

MaterialShip Wt
315L Stainless Steel 51 kg (112 lbs)


Center Section Nickel-Plated Aluminum, Stainless Steel
Air Valve Nickel-Plated Aluminum, Stainless Steel




5.4 m (17.4') Dry, 9.0 m (29.5') Wet


12.7 mm (1/2'')


  • Rubber- 1.0 l (0.27 gal)
  • TPE EZ-Install- 1.0 l (0.27 gal)
  • PTFE Full Stroke- 0.9 l (0.25 gal)
  • Full-Stroke Integral Piston Diaphragm- 1.0 l (0.26 gal)


Elastomer Options

MaterialTemperature Limits
Buna-N -12.2 to +82.2 °C (+10 to +180 °F)
EPDM -51.1 to +137.8 °C (-60 to +280 °F)
PTFE +4.4 to +104.4 °C (+40 to +220 °F)
Saniflex -28.9 to +104.4 °C (+20 to +220 °F)
Wil-Flex -40 to +107.2 °C (-40 to +225 °F)



European Community Regulation 1935/2004/EC

Wilden is pleased to offer Saniflo FDA and Saniflo Hygienic Series (HS) pump models that comply with the European Community Regulation 1935/2004/EC directives for Food Contact Materials. The 1935/2004/EC Regulation requires all pump components intended to come into contact with food must be constructed of approved materials specified in Annex 1 (EC) 1935/2004 and be traceable by heat/batch/lot numbers.

EHEDG (European Hygienic Equipment Design Group)

EHEDG Certification


Wilden is proud to be one of two air-operated double-diaphragm pump companies in the world to be certified by EHEDG, the highest hygienic standard in the world. Wilden’s Saniflo™ Hygienic Series pump design and performance set the standards for equipment used in bio-pharmaceutical and food industries. The Hygienic™ Series pumps are not only designed to meet the demands of safety, performance and hygienic requirements but also ensure the careful transfer of your products.

USP (United States Pharmacopeia)

Wilden's Saniflo HS Series AODD Pumps meet the strict Class VI standards set by the United States Pharmacopeia (USP). The USP is the non-government organization that promotes public health by establishing state-of-the-art standards to ensure the quality of medicines and other health care technologies. Wilden Saniflo HS pumps are in full compliance with USP Class VI standards for sanitary and hygienic use.

3A/SSI (3-A Sanitary Standards, Inc.)

3A Sanitary Certification


Wilden Pump & Engineering, LLC has met the criteria and has obtained the certification needed to pump milk and or dairy products. Wilden is pleased to meet the required demands of the sanitary industry meeting and exceeding customer expectations. You can feel confident when selecting a Wilden pump for your tough pumping applications.

FDA (Food & Drug Administration)


Wilden's Saniflo™ Series utilizes FDA compliant materials to meet the necessary requirements of the Food & Drug Administration. You can now feel confident that Wilden pumps can handle your food or pharmaceutical applications with ease. The FDA compliance is a pledge to our customers that Wilden is 100% behind your industries, offering a multitude of options for your process.

CE Mark (Conformité Européene - European Conformity)


Wilden Pump & Engineering LLC has met the criteria for placing the CE mark on our product line. On December 3, 1999, Wilden fully self-certified its product line by meeting all the regulations of the Machinery and PED (Pressure Equipment) Directives. Every pump manufactured by Wilden will now receive the CE mark. Each pump box will also include a Safety Supplement manual in the eleven official languages of the European Community. This CE mark certification is indicative of Wilden's pledge to providing our distributor network with all the sales tools necessary to excel in a global economy.

ATEX (ATmosphere EXplosible)

Wilden ATEX Product Summary

It is only natural that the worldwide leading producer of air-operated, double-diaphragm pumps complies with the ATEX 100A directive for explosive atmospheres. The European community and their safety are of utmost importance to us. We take responsibility for not only our product, but also for the supporting documentation and compliance of necessary directives. Wilden is proud to introduce our metallic X pumps that comply with ATEX 94/9/EC Group I, category M2 and Group II, category 2 zones G & D. Our plastic X pumps comply with ATEX 94/9/EC Group II, category 2, zone G.



Pro-Flo SHIFT - How It Works Animation

Watch this How It Works Animation to see exactly how Wilden's Pro-Flo SHIFT works compared to other AODD pumps. In this video you will see how the Pro-Flo SHIFT is more simple, reliable, and efficient compared to traditional AODD competitors. It is truly as easy as plug, pump and save!