Improper routing and installation of a glue hose can shorten the service life. With a few simple steps, you can maximize the life of the glue hose, keep employees safe and keep your production lines running.
Proper hose length
For areas where hoses will be installed in a straight line, the length must be longer than the distance from port to port. As the hose is heated, the diameter increases to contain the force of the glue and the length will decrease. Some hoses have decreased in length up to 2 inches.
In this case, if the hose is too short and there isn’t enough slack, the hose fitting connections will be under stress, causing a possible leak. Even worse, a catastrophic failure of the hose breaking loose from the fitting could occur causing pressurized hot adhesive to flow.
On the contrary, too much slack can introduce new issues, such as, hose abrasion and snagging on other machine surfaces.
Proper bend radius
Adhesive hoses are somewhat flexible, but have bend radius limitations. The hose core, fitting crimps and electrical components can be stressed to the point of failure if the hose is bent beyond the maximum recommended bend radius. Call Keystone (800-235-8090) for your hose’s specific recommended maximum bend radius.
Regarding the fitting crimps and bending near the fitting, the suggestion is to keep the hose straight for twice the hose outside diameter. If the hose OD is ½”, keep the hose “straight” beyond the metal fitting for a minimum of one inch. If this is not possible, consider using 90 degree or 45 degree elbow fittings with insulator jackets to accomplish the angle needed without stressing the hose.
Avoiding hose twist
Metal hose cores in a glue hose have mechanical strain limits with regards to twisting. Tighten fittings using two wrenches or “double wrenching”; one to hold the fitting from twisting and the other to tighten the hose connection. To further prevent twisting, limit bending motion of the hose to a single dimensional “plane” when routing. A hose bending only left to right, only up and down or only forward and backward is moving in a single plane. Any combination of left/right, forward/backward, and up/down movement represents 2 planes of motion and all three represent 3 planes of movement. A compound bend can occur with multiple planes of motion and this can cause the hose to twist, since the hose ends are fixed and held tight. Try to limit routing to a single plane, but, if your application requires hose movement to cross multiple planes, ask a Keystone rep for a recommendation.
Abrasion and Attachments
Another cause of premature hose failure is abrasion of the outside hose cover, exposing insulation, wiring and possibly the hose core. Live wires being exposed is a safety issue and should be avoided at all cost. Use proper hose hangers and keep moving hoses from rubbing against other surfaces. Clamps, zip ties and any other restrictive attachments should not be used on hoses since they can press on the wiring and cause hot spots. These hot spots will cause untimely hose failures and could burn through the metal hose core causing an unsafe catastrophic failure.
By following these simple suggestions, you can maximize the service life of your glue hoses. Call or email (email@example.com) Keystone with any questions or requests for recommendations.
Keystone manufactures hoses for Nordson®, Slautterback®, ITW®, HMT®, Graco®, Valco/Melton®, Klebtec® and other hot glue melters for a fraction of the cost of the OEMs. Warranty provided is equal to OEMs.