A PSA on Hot Melt System Purging

April 13, 2023

When you hear the word “purge,” what comes to mind? Maybe it’s the dystopian horror movie franchise with the incredibly creepy masks. Eek. Or maybe you associate purging with what we all do when spring hits and we decide to finally clean out those closets. Also, eek. According to the all-knowing Merriam Webster, purging is to cause evacuation from or to make free of something unwanted.

In the adhesive space, we think of purging when we think of hot melt systems. Depending on how fast production runs, the type of environment your system is in and your preventative maintenance schedule, determines how often your hot melt system may need to be purged to get rid of the buildup of char or other contaminants that can prevent your system from running at tip-top shape.

There are many reasons that you might need to purge your hot melt system. These include:

  • If you are changing adhesives
  • If your pot has char build-up
  • If the glue pot was left on too long (like over a weekend) and the glue degrades and color changes occur
  • Contamination – If the glue pot was left open and contaminants get inside
  • If you need to replace the manifold filter

While the market is full of products and chemicals that promise to easily break down build-up and quickly clean your system, we’ve tested a LOT of them and have found that the results are not up to our expectations. Instead, we recommend a good ole fashion purge. (No creepy mask required.)

For the DIYers

If your hot melt system requires a purge, don’t fret. Most systems have a release valve near the pump that can be opened versus having to purge the system through the hoses. If you’re planning on purging your hot melt system yourself, here are a few things to remember:

  • Gather the required personal protective equipment (PPE) to prevent injury.
  • Leave your system on to begin the purging process.
  • Place a container under the drain valve or adhesive manifold.
  • Depressurize the system before you open the release valve. THIS is a very important step to prevent harm from scalding hot melt adhesive sputtering out of the valve when it is released. Again, always wear personal protection equipment (PPE) when performing this process.
  • After depressurizing, partially open the valve and then slowly increase the pressure to the pump to start the flow of adhesive out of the tank and into the container.
  • Once the adhesive is drained. Depressurize the system again, close the drain valve, and carefully remove char or debris from the tank.

For the CGMers

Prefer to leave the purging to the CGM pros? We understand and we’re always happy to help! If you already have a preventative maintenance plan with CGM, you’re off to a great start. Purging your hot melt system will be a part of that plan. If you don’t have a plan in place with us or you need an un-scheduled hot melt system purge, all it takes is a phone call to us. We’ll have you send the system in, or we can make a visit to your facility to purge on-site.

Purging is a major part of keeping your system running at peak performance. It can be the difference between calling us for preventative maintenance and repair maintenance. No matter if you prefer to purge your system yourself or need a hand, CGM is here to answer your questions, provide any help you need, and most likely, crack a joke or two in the process.