For Longer Scale Life, Just Check the Seal

Regardless of what material your business is in, it’s a given that the scale cannot fail. It costs time and money to be waiting on repairs, doesn’t it? Time and money you don’t have. So, when making those important up-front decisions about what equipment to invest in, I certainly don’t need to remind you this is no area to cut corners.

A scale isn’t a scale without that little device that reads the weight: the load cell. Most systems use more than one. It only takes one crippled load cell to bring an operational scale system to its knees. So this is where getting the right kind of equipment is really going to pay off.

Have you seen a load cell? More often than not it looks like a chunk of steel with a cable dangling from one end. But it’s deceptively delicate — a sensitive electronic device, and believe it or not, vulnerable to creeping moisture, dust, and other particles. While a load cell’s internal gauges are always protected to some extent, sealing quality is quite varied, because, let’s face it, not everyone exposes their scale to dust or moisture. Those of us that do should understand sealing terminology just like we understand IP ratings, to be better consumers and, ultimately, get the performance we need from our scale equipment.

Let’s start with simple weighing tasks. At a minimum, most load cells are environmentally sealed. What does that mean? It means that the internal gauge area is protected with potting, and depending on design, you may find either a rubber boot or glued metal plate protecting that area too. Environmentally sealed load cells are meant for basic indoor/outdoor use, not frequent moisture or dust contact. You’ll find these cells made from a variety of material, including aluminum, alloy, or stainless steel.

If your job is at a higher risk for moisture contact you may want to consider a welded seal design. The majority of welded seal models are stainless steel. You’ll find a metal plate or cup welded directly to the gauge area and they can be used in many applications where occasionally moisture and dust is a factor.

But for those really dirty jobs, look for something that’s hermetically sealed. Hermetic sealing implies that something is impervious to gas or air. These exclusive stainless steel cells not only have a welded seal to protect the strain gauge, but also extra protection in the cable entry area, making them well suited for heavy washdown jobs.

As you can see, when it comes to keeping your scale running its best, a little homework and preparation goes a long way. If you’d like to learn more, Rice Lake offers a Load Cell and Weigh Module Handbook and an LCWM Resource Center at www.ricelake.com/lcwm.

Paul Menge has worked in the weighing industry for more than 30 years, the past 13 as load cell product manager for Rice Lake Weighing Systems, Rice Lake, WI.