Instrumented Air Cylinders
May 8, 2023
The Vollrath LLC 
which makes a wide variety of professional kitchen and service items for the food and drinks industry from ketchup squirt bottles to stainless steel cookware, was looking for a solution to automate the positioning of the bottom die of the hydraulic press used to manufacture trays for steam tables and salad bars. Operators formerly had to set the depth of the die manually, which ate into productivity. Instead, Werner Kraenzler, Manufacturing Engineer at Vollrath, discovered the iNSiGHT air cylinder from Motion Controls, which incorporated Quantitative Variable Light Emission (QVLA) technology for internally sensing position and avoided the need for linear pots, which were not suitable due to the hydraulic press’s repeated shock. QVLA uses light from an LED, which illuminates the volume inside the cap end of the cylinder, and as the piston moves closer to or away from the cap end, the intensity of the reflected light changes – this correlates to the piston’s position inside the cylinder, and circuitry within the QVLA generates an electrical signal representative of piston position accurately, without the need for magnets or gun-drilled piston rods.
