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Solenoid Valves - Minimum Differential Explained

Solenoid Valves - Minimum Differential Explained

Featured products the 6213 and the 6281 solenoid valves for on / off operation

A typical problem that is always being raised and occurs more than it should is: ‘I have recently purchased a solenoid valve and it leaks’. Obviously that is not a good outcome. Our experience finds that the problem is one of three things:-

A. There is debris in the valve and is stopping it from closing

B. The seal is not the right one for the fluid ie. oil eats into EPDM and NBR should be used

C. There is not enough differential pressure in the line to assist the valve from opening fully or closing

With item A and B the solution is simple, make sure the pipe line is free from debris before fitting it (a good idea is to always fit some form of filter/strainer) and secondly check the compatibility of fluid being used against the seal material before ordering, we have a good chemical resistance chart that will assist you with selection or just give us a ring and we will be glad to help.

The third problem is a bit more difficult to understand and is explained and shows the differences in designs of solenoids in The Knowledge which you can download by clicking this link.

However in brief the customer has probably purchased a servo assisted valve which needs a minimum differential pressure to work fully and our servo assisted valves need a minimum pressure to operate. What people don’t understand is that to achieve a 1 bar head (fed by gravity) you need to have 10 metres of head and that is irrespective of volume.

These solenoid valves from the new product series EV are suitable for a broad spectrum of standard applications for fluid and gaseous media.

Typical applications are water, compressed air and vacuum such as to be found in car washes, drinking water treatment plants, swimming pool technologies, heating and refrigerating systems.


6213

EV6213 0-10 Bar ¼”-2" Various seals Body in Brass and St St Normally Closed Various Voltages

The 6213 EV valve is a servo-assisted solenoid valve of the EV series. The spring coupling of the diaphragm supports the opening process of the valve. In its standard version, the valve is suitable for use in liquids. A minimum differential pressure is required for complete opening.

A special version (HP00) which opens the valve without differential pressure is available for gas and vacuum applications. Various diaphragm material combinations are available depending on the application.

The standard brass housing satisfies all European drinking water requirements. Lead-free or dezincification-resistant brass types are available for other markets. The housing offering is rounded out by a stainless steel version.

The solenoid coils are moulded with a chemically resistant epoxy. For reduced energy requirement, all coils can be delivered with electronic power reduction.

6213 dataIn combination with a plug in accordance with DIN EN 175301-803 Form A, the valves satisfy protection class IP65 – in combination with a stainless steel housing NEMA 4X.

  • Servo-assisted diaphragm with diameter of up to DN40
  • Spring coupled diaphragm opens without differential pressure
  • Vibration-proof, screwed coil system
  • Damped design for quiet closing
  • Compact construction with high flow rate
  • Opens without differential pressure
  • Short installation length
  • Water hammer free and low audible noise
  • High flow rate for small process connections
  • Sealed and bolted coil system

6213 brass6213 Stainless Steel


 

6281

EV6281 0.5 -16 Bar 1/2”- 2"Various Seals Body in Brass and St St Normally Closed and Normally Open Various Voltages

The 6281 valve is a servo-assisted solenoid valve of the EV series. A minimum differential pressure is always required for the proper function of the valve.

Various diaphragm material combinations and methods of operation are available depending on the application. The standard brass housing satisfies all European drinking water requirements. Dezincification-resistant brass is available for other markets. The housing offering is rounded out by a stainless steel version. The solenoid coils are moulded with a chemically resistant epoxy.

For reduced energy requirement, all coils can be delivered with electronic power reduction. The valve can be equipped with manual override for easy maintenance and commissioning. In combination with a plug in accordance with DIN EN 175301-803 Form A, the valves satisfy protection class IP65 – in combination with a stainless steel housing NEMA 4X. 6281 data

  • Servo-assisted diaphragm with diameter of up to DN50
  • Vibration-proof, central screwed coil system
  • Damped design for quiet closing
  • Moulded housing with high surface quality
  • Service-friendly manual override
  • Water hammer free and low noise
  • Short installation length
  • High flow rate for small process connections
  • Sealed and bolted coil system
  • Low power consumption
  • Universal and flexible with options:
    • Manual override
    • Version: normally opened (NO)
    • Explosion proof version

6281 atex6281 Brass6281 Stainless Steel


 

The information below is a very basic diagram aimed to give a general idea of servo assisted valves compared to the direct acting.

6213, 6281 compare diagram

The information below is assuming that there is a constant minimum head of 0.2 Bar

0.2bar


More Information:

Frequently Asked Questions about Solenoid Valves

Free Download - Solenoid Selection & Conversion Chart

Free Download - The Knowledge on Solenoid Valves  



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