U.S.-based Westermeyer Industries displayed its newly released RDP-01T Differential Pressure Monitor and its Serviceable Oil Strainer with an integrated sight glass to support service and diagnostics of oil filters and compressors used in transcritical CO2 (R744) systems at the 2023 AHR Expo.

The AHR Expo took place February 6-8 at the Georgia World Congress Center in Atlanta, Georgia.

The monitor determines when to change the filter in a coalescing oil separator by measuring the pressure drop across the filter “with very high accuracy,” said Gary Westermeyer, President and General Manager of Westermeyer Industries, a division of Mueller Industries. The filter is contaminated and requires changing when there is a 12psi (0.8bar) pressure drop across the filter. The analog devices currently in use have a needle to read the pressure change and are “not very accurate,” he added.

Westermeyer Industries took its monitor designed for non-natural refrigerants and redesigned it for CO2 systems. “This is a patented product and the transducers are calibrated to one another throughout the software inside our monitor,” he said, adding that checking the pressure drop across the filter for transcritical CO2 coalescing oil separators is new for the industry.

The monitor is housed in stainless steel with a maximum operating pressure of 2,174psi (150bar).

Need for CO2 strainer  

Oil strainers, located between the oil separator and the compressor, serve as a final oil filter and confirm the flow of oil. For diagnostic purposes, “we’ve learned from customers there is a need for strainers that are rated for the high pressures involved in CO2 [refrigeration],” said Westermeyer.  If there is an oil issue, the service person needs to understand if the oil is flowing back to the compressor from the oil separator, but this requires a sight glass.

“Non-natural refrigerants have a sight glass, but nobody’s been able to do it for CO2 just because of the pressure,” Westermeyer said. “This strainer is a high-pressure device with a hermetically sealed sight glass that is rated for 140bar [2,030psi], and we are the only ones who have it.” The serviceable strainer basket is contained in a nickel-plated steel enclosure and is designed for transcritical CO2 units.

The strainer removes additional particulates that may flow from the oil separator back to the compressor, especially during the initial startup of a system with new piping that has been freshly welded or brazed, said Westermeyer. Visual inspection with the sight glass helps determine when it should be replaced.

Westermeyer Industries designs, manufactures and distributes components for the refrigeration and air conditioning industry with commercial and industrial applications. The company started in 2001 and has been in the CO2 business for at least five years, said Westermeyer, with a 100,000ft2 (9,290m2) plant operating in Bluff, Illinois.

“We strive to be component and accessory problem-solvers,” says Westermeyer Industries on its website. “Our goal is to enhance product efficiencies and increase reliability, so we are constantly looking for ways to improve existing products, along with the research and development of new designs,”

At the 2023 AHR Expo, Westermeyer said, “We have more new products coming this year.”

“This strainer is a high-pressure device with a hermetically sealed sight glass that is rated for 140bar (2,030psi), and we are the only ones who have it.”

Gary Westermeyer, President and General Manager, Westermeyer Industries