Heat (Impulse) Sealers

INTRODUCTION

Heat sealing is accomplished by applying pressure and heat to melt fi lms and bond them together, providing a safe environment for the food contents inside (Kun-xiu & Sheng-hai, 2013).

When working with foil pouches, heat impulse sealers should be used. One theory of heat sealing is to use an iron to seal a package instead of a heat impulse sealer. However, using an iron will not seal the package properly, especially for powdered products (Korn, 2013).

Heat impulse sealers are available at most home storage centers.

CRITICAL FACTORS IN SEALING

Critical factors in heat sealing include the seal bar temperature, the pressure put on the seal by the sealing bars, and the time seal bar pressure is applied on the seal (FDA, 2009). Increasing seal pressure above the amount required will not improve the sealing and may result in thinning of fi lms at the seal (Baer et al., 1998). Instructions provided with the sealing unit should be followed.

It is important to make sure that the seal area is not contaminated with food, grease, moisture, or some other contaminant that may weaken or prevent the seal. Th e sealing surface should be smooth, parallel, and wrinkle and contaminant free.

TESTING SEALS

Aft er the process of sealing, look over seams to make sure they are adequate and don’t have burn spots. If seams are burned, decrease the sealing setting by one quarter step. You should not be able to pull the seam apart. If seam can be pulled apart, the seam area of the machine may need to be cleaned or the pouch may be too full. If needed, the sealing setting may be increased by one quarter step, then reseal the pouch. Pressing on the package should not cause leaks (Kropf, 2004).