Confirm the exact configuration
Use the manufacturer part number and model code—not appearance alone. Connection, size, material, voltage, pressure, seal, and control options can differ within the same product family.
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Festo
531991
Soft-start valve MS4N-DL-1/4
The Festo 531991 is a direct-controlled 2/2 pneumatic industrial component featuring a piston seat structural design with a mechanical spring reset and a non-reversible flow direction. It operates with an adjustable exhaust air function, an external pilot air supply port, and a normal nominal flow rate of 2000 l/min at an operating pressure range of 4 bar to 14 bar using compressed air or inert gases. Built with a moderate corrosion resistance class of CRC 2 and VDMA24364-B1/B2-L LABS conformity, this component functions within a medium temperature range of -10 °C to 60 °C and allows for optional oil lubrication. Submit the exact part number, quantity, and application requirements to request a quote.
Request pricing and availabilityCommercial response within one business day for your destination and required quantity.
Request a QuoteWhy no listed price?
Industrial and obsolete parts are priced per enquiry: the final price depends on available stock, condition, quantity, and your delivery destination, so a fixed list price would be misleading. Request a quote and we confirm current pricing, lead time, and sourcing options — including hard-to-find and discontinued Festo references — within one business day.
- Manufacturer
- Festo
- Part number
- 531991
- Data verification
- Manufacturer evidence reviewed
For a faster response, include quantity, condition, and delivery destination.
Exact part-number verificationTechnical properties are matched to 531991.
Worldwide sourcingSupport for planned and urgent industrial requirements.
Manufacturer documentationA document is added when the reviewed source provides one.
Verified configuration
Technical Specifications
- Exhaust air function
- Adjustable
- Actuation type
- Pneumatic
- Mounting position
- Any
- Manual override
- None
- Structural design
- Piston seat
- Reset method
- Mechanical spring
- Type of control
- directly
- Pilot air supply port
- External
- Flow direction
- Non-reversible
- Valve function
- 2/2
- Operating pressure
- 4 bar...14 bar
- b-value
- 0.45
- C value
- 9.6 l/sbar
- Normal nominal ow rate (normalized to DIN 1343)
- 2000 l/min
- Operating medium
- Compressed air as per ISO 8573-1:2010 [7:4:4] | Inert gases
- Information on operating and pilot media
- Operation with oil lubrication possible (required for further use)
- Corrosion resistance class (CRC)
- 2 - Moderate corrosion stress
- LABS (PWIS) conformity
- VDMA24364-B1/B2-L
- For use in the food industry
- See supplementary material information
- Temperature of medium
- -10 °C...60 °C
- Ambient temperature
- -10 °C...60 °C
- Product weight
- 213 g
- Type of mounting
- Alternatively: | In-line installation | With accessories
- Pneumatic connection 1
- 1/4 NPT
- Pneumatic connection 2
- 1/4 NPT
- Note on materials
- RoHS compliant
- Seals material
- NBR
- Housing material
- Die-cast aluminum
Engineering context
Identification and RFQ Guidance
What to include in your RFQ
Provide quantity, delivery country and ZIP/postal code, required condition, target date, and photographs of the existing nameplate when available.
Technical verification
Our sourcing response is prepared against Festo 531991. Final compatibility remains subject to the machine manufacturer’s requirements and complete application data.