Howden compressors are very common in the oil, gas, and chemical industries. In my opinion they're the best refrigeration screw compressor on the market with Mycom as a close second. I've used Howden compressors in just about every refrigeration application, from R-22, Ammonia to Propane and Helium. I've also used them to compress natural gas being supplied to gas turbine generators and compressing sour gas with high concentrations of H2S. They can take a beating and keep on running.
I don't have an electronic IOM but if I have time I'll scan one of the old fashion manuals.