Need a valve that can handle pressure on the outlet . . . 2

[justonwo]

I've been doing web searches for quite some time trying to find a solenoid valve capable of sealing off liquid flow even if a large differential pressure exists between the outlet and the inlet or vice versa. In other words, the valve should remain tightly closed in both of the following situations:

1) 100 psig on the inlet, 0 psig on the outlet
2) 0 psig on the inlet, 100 psig on the outlet

Most solenoid valves I'm aware of will open if outlet pressure greatly exceeds inlet pressure.

Furthermore, I need a valve with a Cv of 1.5 or greater to keep my pressure drop in a reasonable range. I have yet to find a valve that meets all these criteria (on, and material compatibility with DI water and glycerin). I've used keywords like "bi-directional" but I'm not sure if that's what I want or not.

What is the common name for a valve with these characteristics? Who supplies them?

Many thanks.

Juston

 

[hydtools]

Circle Seal?

http://www.circlesealcontrols.com/products/solenoid_valves/sv_series.html

Ted

 

[justonwo]

Yep, I contacted those guys. Unfortunately, they don't have the size valve I need. I believe their largest Cv is much less than 1.

 

[Joesteam]

Why not use an actuated ball type valve rather than a solenoid. Many manufacturers make bubble tight shut-off valves with 100 psig in either direction.

Joe Lambert

http://www.control-associates.com/

 

[DRWeig]

Joe hit the nail on the head. I vote ball valve too.

Let us know what you decide to do!

Good on ya,

Goober Dave

 

[JLSeagull]

Yup. Use a small solenoid valve on low-pressure instrument air to pilot the actuator on the ball valve.

You might look at Maxon for solenoid valves with more horse-power. Unless there is something special, I would go with the actuated ball valve.

 

[justonwo]

What is the footprint of these actuated ball valves? The only issue for me is that I will have a relatively high density of valves in one spot.

Thanks for the tips. This is an avenue a colleague of mine also suggested I pursue.

 

[btrueblood]

You could also search for balanced-poppet or pressure-balanced poppet solenoid valves. Asco makes some, but the Cv's were in the 0.5 range.

 

[JLSeagull]

The footprint and weight can vary greatly. Search for a "Whitey" valve with a pneumatic actuator from the Swagelok site. This should work for a Cv below 2. If the valve becomes too large then you might look at an Apollo valve - perhaps with a small rack and pinion actuator. Assure that the actuator is single acting (spring return) if there is a failure position.

 

[moltenmetal]

Your problem is with trying to find a large Cv direct-operated solenoid valve which will resist the differential pressure you need. Everything with a large enough Cv and max pressure for your needs is pilot operated. They rely on pressure differential between the upstream and downstream ports to actuate and to seal, or they require a low-pressure vent or return (eg. a spool valve). Hence the problem with bi-directional sealing.

There's only so much force you can get out of an 8-watt or 12-watt solenoid coil!

Burkert and Spirax Sarco both sell a small threaded air piston-actuated Y-pattern valve. Double acting and spring return versions are available. May be physically smaller and will probably be cheaper than the actuated Whitey valve option- if you have instrument air available.

Kitz amongst others has a small commodity 2pc threaded ball valve with close coupled actuator (CSAUTE).

 

[gerhardl]

1. If you want to use a solenoid valve, you have a possible solution in a solenoid valve, universal type,and 3/2, where one port can be plugged, the two others giving a normal 2/2 on/off action. Theese exists (still, I believe), see below at the Norgren (Herion series from Germany) site:

http://www.norgren.com/document_resources/EN/N_UK_5_4_375_24100.pdf

Note the large size and wattage for the solenoids!

2. Secondly you could of course use a normal 2/2 solenoid valve with forced lifting, plus a disc-type checkvalve at the downpressure side to avoid lifting if pressure direction reverts. To obtain flow both ways, however, you have to use two of theese solutions in parallell, working in opposite directions.

3. The conclusion is as answered above: cheapest and best is most often to use a ball valve. Or, as I have found on many occasions, a high quality y-type globe valve with pneumatic actuator and spring return.

 

[justonwo]

Gerhard,

Just to make sure I understand correctly, for the Norgren valve in option 1 . . . I could, for example, block off port 1 and connect ports 2 and 3 for normally closed operation.

Can I then pressurize either port 2 and port 3 without leakage (say 100 psig on port 2 and 0 psig on port 3 OR 100 psig on port 3 and 0 psig on port 1). What is it about the design of this valve that prevents leakage regardless of which side is pressurized?

 

[justonwo]

Wow, checked into the cost of that Norgren valve. $3800. I couldn't believe it.

 

[gerhardl]

Yes, you are correct. This is also shown in the solenoid valve functional symbol:

Arrow symbols pointing in both directions meaning flow or pressure for the whole given range in both directions.

1,2, and 3 representing ports. Small rectangle to the left symbolizing solenoid operation, and left square showing flow and connections when solenoid is operated. In the same way right square showing situation when the valve is operated by the spring return, spring symbol to the righthand end.

No secrets: sufficient spring force to close, and strong enoough solenoid to operate to 'open' (opposite) situation, and good mechanical construction.

I know the valve well, no negative effects if you block one port, more important to remember the general restrictions for use of fluids with solenoid valves: temperature limits, compabillity to sealings and other materials, viscosity limits, no dirt or residues - only clean fluids, no fluids or situations where (rest) fluid can dry up and give gluing or abrasive effects.

But yes: the price and size is in such a range that that you will want to check cheaper technicl solutions first.

Typical (of many possible) uses for this valve (as 3/2): actuator operation for large pneumatical actuators, where large flow and fast opening or closing is required. Can also be used in series as redundant emergency shut down for actuators.

The solution compeats against pilot operated solenoid valves with several advantages: dependabel and robust construction, probably liftime length, closing down to zero bar G, and even going very far into the vacuum range, and the bi-directional flow possibillity.