Confirmation of the move came after several days of speculation fuelled by insiders who had claimed the closure announcement was to be made on a May bank holiday.
Now workers have been told management plan to shut its Howden Compressors' Barfillan Drive site in Glasgow and transfer production to a sister site in Renfrew.
The closure-threatened plant in Craigton has operated for at least 50 years and currently employs more than 100 workers.
Howden chiefs warned part of the production process will be switched to other plants in Europe, which will result in the loss of around a fifth of the workforce.
The American owned engineering giant owns two compressor-related companies which serve major sectors including oil and gas - Howden Compressors Ltd (HCL) and Howden Power Compressors (HPC).
Global HR Director Donnah Malone said: "Our compressor companies face a relentless challenge to stay competitive and we intend to consolidate our Glasgow operations of HCL and HPC on a single site at our Renfrew location which is also home to Howden Group, Howden Technology, Howden UK and Howden Process Compressors.
"This will allow us to retain and re-locate the majority of the skilled manufacturing and engineering work in Renfrew with some high-volume products transferring to European factories where overheads are lower.
"Our Renfrew operations will continue to play a core role in compressor research, engineering, and sales. These proposals could result in the regrettable loss of HCL employees. At present we would estimate that between 15 and 20 roles may be affected in the initial transfer phase."
The announcement came exactly six months to the day after the American owners bought a rival compressor manufacturer in Prague. There are now fears that the entire production will eventually switch from Renfrew to the Czech Republic.
Kenny Jordan, of the Unite union, is demanding long-term assurances.
He said: "They talk about this being the initial phase with further phases later on. This looks to me like the thin edge of the wedge."