Are vacuum pumps supposed to smoke?

October 28, 2019 1:51 pm Published by

When you add a new piece of equipment it is wise to do some research into how it operates and what you can expect from it by way of noises, smells and discharges. Top of the list of concerned calls is smoke coming from vacuum pumps.

In many cases, the smoke you see is mechanical pump oil vapour. It is easy to assume that whenever there is smoke being emitted from the pump, it means there is something wrong with the machine. Oil vapour or oil mist is a natural by-product of creating vacuum in an oil sealed mechanical pump. As well as lubricating the moving parts, the oil is used to seal the fine clearances in the pump. While this high-speed movement of oil is excellent for stopping air leakage inside the pump, the oil flow creates a mist on the exhaust side of the pump.

Some designs of vacuum pumps contain an internal oil mist separator in the exhaust cavity. It usually remains closed with a cover plate. This part is made of a fibrous material that gets wet when oil passes through it. The more the oil passes through, the greater the chances of smoke discharge when the pump is operating in full throttle.

There are however some occasions when smoke can be an indicator of a potential problem. As the pump ages the oil mist separator can become clogged with contaminants.  This will restrict the flow of air through the oil mist separator and increase the back pressure against the pump. This can cause damage to the seals and possibly the pump to seize. Oil mist separator elements should be replaced before they reach this stage

Another sign that smoke is a problem can be abnormal noises from the pump. If foreign objects get trapped inside the pump you might notice heavy smoke from the oil reservoir. There may also be erratic noises and vibrations and you may find the vacuum level slipping. This can be a severe problem. If you suspect there is debris or contamination in the vacuum pump, try changing the oil. If this does not improve performance get in touch with Harrier Pneumatics.

Something to watch out for is not overloading the pump with water. This will reduce its efficiency and increase the risk of a malfunction. An indication you need to check water level is a noisy pump and excessive smoke.

Understanding what you should expect from oil mist levels during operation can help you spot when something is amiss during operation. Addressing issues with excessive smoke or unusual noises as soon as they occur will help to extend the lifespan of the pump. Harrier Pneumatics have been selling, installing and servicing air compressors for over 25 years. Our Service teams will provide a regular maintenance and servicing regime to ensure your equipment performs efficiently. Get in touch to discuss your vacuum pump requirements.

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This post was written by Hilary Dean