There are several different types of solenoid valves used for hot melt application equipment. We are specifically referencing gun applicator solenoids in this article. The gun solenoid is what is used to fire the gun and apply the glue onto boxes in a packaging line. The two most common types of solenoids used to fire automatic pneumatic glue guns are 4-way and 3-way. The difference between the two is simple: a 4-way solenoid is used when you have an air open/air closed gun and a 3-way is used for an air open/spring closed gun. Essentially, a 4-way solenoid utilizes pneumatic pressure to open the piston, initiating glue flow, and close the piston to shut off glue flow. Whereas a 3-way solenoid utilizes pneumatic pressure to open the piston and when the air shuts off an internal spring closes the piston, shutting off glue flow.
Now let us say your packaging facility has multiple glue lines, and some are air open/air close applicator systems and some are air open/spring close applicator systems. You can standardize your inventory by purchasing only 4-way solenoids and converting them to 3-way on an as needed basis. However, please note that you cannot run a 3-way as a 4-way.
Below are the steps to change a 4-way solenoid valve into a 3-way solenoid valve:
- Remove air line #2 from solenoid
- Plug air line #2 on solenoid with a ¼ NPT flush plug
It’s that easy!
For any further questions about solenoids, give a sales rep at Universal Systems a call at 561-272-5442 or email us at sales@ussefl.com.