There are many different types of solenoid valves available, and many companies that make them.
When selecting a solenoid valve, you must pay attention to:
A two-way valve has two ports.
When power is applied, the pressure flows from one port to the other.
With pressure off, the flow ceases.
[Assuming a normally-closed valve, which is almost always the case.]
A three-way valve has three ports.
When power is on, one of the ports is connected to the common port, and pressure flows through to extend the pneumatic cylinder.
When power is off, the other port is connected to the common port, and pressure is exhausted to reset the cylinder.
This is the pneumatic equivalent of a single-pole single-throw electrical switch.
A four-way valve has four ports.
With power on, one set of ports is connected straight through to the other set of ports.
With power off, the connection is reversed.
If a valve has more ports than you need, you can plug them up to get a lesser configuration.
A four-way valve can act as a three-way by plugging one of the ports.
A four-way valve can act as a two-way by plugging two of the ports.
A three-way valve can act as a two-way by plugging one of the ports.
Does it come with paperwork? Does the seller have an identical valve that does have paperwork? Even items in a surplus catalog usually have some information.
Look for an engraved plate somewhere on the valve. Such plates are very common, and usually specify power supply and working pressure.
Look for a manufacturer's name and model number. Then contact the manufacturer (search them up on the web) and ask for specifications.
Note: Very generic information isn't terribly helpful. There must be hundreds of different models of ASCO "Red Hat" solenoid valves, with many different operating specifications.
Start by counting the number of "ports" through which air enters and exits the valve. If the valve is relatively new, the ports may be plugged with dust caps. Remove them so you can get a look inside and verify that it is a port. Before removing something, make sure it is a port, and not part of the valve.
The blue plastic bits are plugs that protect ports.
The red plastic bit is part of the valve - leave it alone!
Once you know the number of ports, you can look for likely configurations under Valve Types.
You should also look for connection information on the valve itself.
This Mac valve has a little connection diagram on the valve. It indicates how the numbered ports are connected with power (on the right) and without power (on the left). This diagram only indicates the flow. It does not indicate the physical position of the ports.
Note that each port has a number stamped next to it.
Port 1 is on the right, port 2 is on the left, and port 3 (number is obscured by the brass fitting) is in the middle.
Another thing to look for is arrows stamped on the body of the valve, indicating direction of air flow. Sometimes, ports are stamped "IN" and "OUT".
Your solenoid valve should come with a specification sheet that includes wiring information. If not, see Identification Of Surplus Valves.
A solenoid valve that operates on 110 VAC line current may have three wires.
In this case: green is ground, one red is hot, one red is neutral.
If your solenoid valve operates on 110 VAC line current and has only two wires, one is hot and the other neutral.
You might also want to check out our section on power wiring.
It's a good idea to put a fuse in series with the "hot" wire.
(only rated for 50 PSI)
The look of this valve doesn't quite match the specification sheets from Mead,
which suggests that this is an earlier model.
Dennis found these for $10 apiece in the surplus bins at Coast Pneumatics. [September 2005] Don't bother looking - he cleaned them out.
The spec sheet for this model of valve provides the following characteristics:
|Manufacturer||Mead Fluid Dynamics, http://www.mead-usa.com/|
|Description||4-way double solenoid valve|
|Pressure Range||25 to 100 PSI (non-solenoid models in the LTV family can go to 125 PSI)|
|Temperature||0 degrees F to 115 degrees F|
|Flow||14 SCFM at 100 PSI|
|Response time||20-30 mS|
|Solenoid||24 VDC (available in 12 VDC, 24 VDC (4.85 watts), 24 VAC or 120 VAC (50/60 Hz, 4.75 watts))|
The valve was equipped with 5 well-marked ports:
Note: There does exist a monostable version of this valve, the single solenoid LTV-115. But that's not what we found for $10 apiece in the surplus bins.
Looking at the solenoid coils:
Some of this technical information came from:
You should also check on eBay. [Reader Thanh Quach reports that eBay has solenoid valves listed quite regularly. "There is usually at least one or two every couple of weeks or so. They generally go for under $30 shipped."]
The web sites of solenoid valve manufacturers can provide product information, as well as dealer referals:
Thank you for visiting. Your comments are welcome.
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