Sensors and Cordsets for Wash down Conditions

By: Scott D’Amico, Sr. Technical Support Engineer, ifm efector, Exton, PA

In the food industry, wash down conditions can test the most rugged materials. Cleaning solvents and industrial chemicals play havoc on a daily basis throughout food plants. High-pressure cleanings can cause liquid ingress and fluctuating temperatures create thermal shock conditions. Stainless steel equipment can withstand this harsh environment, however, it’s the peripheral sensors and controls that can make or break the performance of a machine.

Tipper Tie, Inc. (Apex, NC), an original equipment manufacturer of packaging equipment for the food industry, found that sourced position sensors and cordsets used on their machines were not remaining reliable due to their customers’ extreme wash down conditions.

Sensors were experiencing reduced life on a variety of Tipper’s machines including Tipper Netters, which automate the process of loading, netting and clipping large food products such as bone-in hams, small briskets and molded items. The sensors were short circuiting due to the daily high-pressure wash downs that caused water to seep inside the sensor housing.

More than 20 cylinder sensors are needed to monitor piston position on the machines’ various tie-rod and smooth-style pneumatic cylinders. The Tipper Netters use a breach load so that an operator only has to place and orient the food product which is then automatically sent through the machine and netted – up to 10 pieces per minute. Inductive proximity sensors are also used to detect the position and rotation of metal clips that close the netting around the food product.

When you’re only as strong as your weakest link, the failing sensors were considered unreliable, and for Sam Griggs, R&D Project Manager at Tipper Tie, this was a problem. “In the overall scheme of things, position sensors should be a small piece of the puzzle,” says Griggs. “They should be something I don’t have to think about.”

And, unfortunately, Griggs was thinking about them.

Determined to uphold Tipper Tie’s stellar reputation for customer service and quality, Griggs sought a solution for his machines. “Our engineers design with sanitation and wash down processes in mind, and our customers depend on Tipper Tie equipment to withstand wash down environments.”

To Griggs, it only made sense that If Tipper Tie machines are designed for wash down conditions, so should their sensors and controls. After reviewing alternative sensors, Griggs decided to try the MK Series wash down cylinder sensors from ifm efector (Exton, PA). Rated IP69K for extreme wash down conditions, ifm’s cylinder sensors are injection molded, completely sealing the housing from liquid ingress. The sensors are designed and tested to withstand thermal shock, vibration, and 1500-psi pressure sprays.

ifm cylinder sensors incorporate giant magneto resistive (GMR) technology that enables the sensor to provide an unlimited number of switching cycles, offering a long lifespan – possibly as long as the cylinder itself. Fast response times, consistent repeatability, and high sensitivity are a result of GMR technology which maintains the sensor’s accuracy in high-speed applications.

Mounting was an issue with Griggs because of the difficulty in connecting and accidentally cross-threading the previous sensor’s plastic connectors. As an alternative, ifm’s cylinder sensors are compact – only 25mm long – and offer a pigtail cable with a durable M12 connector that holds up in wash down conditions. “It’s now easier to get to the connection with the M12 pigtail,” says Griggs. For status indication, the sensor features a bright LED that shines through the sensor housing. ifm efector offers a variety of mounting accessories that enable the same sensor to be used for multiple cylinder styles.

To monitor the position and rotation of the metal clips – known as Tipper Clips, the company’s first product line – Tipper Tie applied ifm‘s T Series wash down proximity sensors. Rated IP69K and designed for wash down environments, the sensors feature 316 stainless steel housings and an FDA-approved PEEK sensing face that withstand thermal shock conditions. The sensor’s zero-leak design and 0-100°C temperature rating is ideal for high temperature applications. Laser-etched part numbers eliminate the need for labels that can wear off during pressure cleanings.

Griggs last hurdle was the cordset. He applied ifm’s wash down Micro DC patch cords to both ifm cylinder and proximity sensors. The PVC-jacketed patch cords are designed and IP69K tested for wash down environments and feature stainless steel coupling nuts, gold-plated contacts, and EPDM O-rings.

According to Griggs, the solution proved successful. “The combination is working. We’ve switched 90% of our sensors over to ifm efector wash down sensors and patch cords.” By applying sensors and controls designed specifically for their industrial environment, Tipper Tie has reduced machine downtime and simplified installation.

And, more importantly, Sam Griggs doesn’t have to think about sensors anymore.

For more information about Tipper Tie equipment and products, visit www.tippertie.com. For information about ifm efector sensors and controls, visit www.ifmefector.com