Screw refrigeration compressor
A refrigeration unit: its output is judged not by how fast the receiver fills, but by how often the compressor starts up to hold the temperature in the chamber.
Screw refrigeration compressor, 200 l oil sump
The class norm is 0.8 ml per litre in 5 stages. For the refrigeration unit, 1.5 ml/l in 3 stages has been assigned. Screw and centrifugal compressors →
What is treated
- A serviceable screw compressor with no parts worn 100 %.
- Fine filters flushed or replaced, centrifuge flushed.
What is measured before and after
| Parameter | Instrument | How and when |
|---|---|---|
| Output — time to fill the receiver to a fixed pressure | stopwatch | — |
| Power draw or current with the compressor unloaded and at a fixed pressure | clamp meter, wattmeter | — |
| Oil pressure in the lubrication system | standard pressure gauge | At operating temperature. |
| Output — by start-up frequency | observation and stopwatch | How many times the compressor starts up to hold a fixed temperature in the cold chamber. |
Dosage rates
| Compound | Rate | How and when |
|---|---|---|
| Gel for compressors and bearings | 1.5 ml per 1 litre of the standard oil per stage | 200 l sump: 300 ml per stage, 900 ml for three stages. |
Treatment stages
- In a separate vessel, dilute the gel in standard oil heated to 50–60 °C (1 part gel to 5–10 parts oil), stir until fully dissolved and add to the crankcase of the warmed-up compressor.Start of total operating-time count
- The second stage is the same as the first.After 8–12 hours of total operating time
- The third stage is the same as the first.After a further 8–12 hours of operating time
After treatment
- Treatment is complete after 350 hours of total operating time — the shortest cycle among the machines analysed.
- The declared service-life gain is not less than twofold.
Points to watch
- Replace the oil if less than 50 % of its service life remains.
- After application — 10–15 minutes of idling without pressure load.
Source: XADO applied procedure, lead engineer I. N. Sharaikin. Class norm — instruction IE-24.6-25612000-005-2008, procedure No. 2.