Orange County Vacuum

Preventive Maintenance of Vacuum Pumps

Lack of preventive maintenance is the biggest reason why oil filled vacuum pumps fail. While everything mechanical wears out at some point, if you follow some very basic recommendations as listed below, you should notice an increase in uptime and decrease in cost of ownership and repairs.    The Right Fluid for your Application Gas Ballasting Periodic Fluid Changes.  How often should it be done? Trapping, Inlet and Exhaust Filtering ·

Contaminated pump

 The Right Fluid for Your Pump and Application

Start by filling your pump to the proper level with the correct fluid.  Refer to your manual for specific instructions and details. Don’t have one?  Ask OCV, we have some on .pdf and can obtain most others from the manufacturers. 

First, it is important to understand the function of vacuum pump fluid.  Clean fluid is necessary to lubricate, seal and cool the component parts of mechanical pumps. Choice of proper fluid is a major consideration and following the fluid recommendation of the O.E.M. for your specific pump is a good start. It is possible to fine tune the performance of your pump and increase reliability with "better" fluid.  The process of determining what a better fluid is begins with the customer telling us the application of the pump and chemicals it is subject to.  The second step is for us to consult with the chemists at Inland Vacuum for their recommendation, which we will pass on to you.  

Gas Ballasting

Based on my experience of ten years in the vacuum pump service business, I would venture a guess that through no fault of their own, 50-75% of the scientists that use vacuum pumps have no idea what a gas ballast control is. I preach use of it every opportunity that I have.   

Nearly all oil filled mechanical pumps have gas ballast valves or controls and you will find a detailed explanation about where to find it and how to use it in your pump manual.  Generally speaking, the gas ballast serves the function of heating up the pump in a controlled manner in order to bake out condensables such as water and solvents.  It is not a substitute for a fluid change, but in the case of less severe contamination, will restore the performance of the pump if loaded with condensables. You should see an immediate improvement in ultimate vacuum after the gas ballasting period of minutes or hours.  Some fluid is expended out the exhaust during ballasting, so monitor the fluid level periodically while the ballast control is open. Note that your pump is valved off from the system during ballasting.

How often should I change my fluid? This is without a doubt the question that comes up the most.  My answer is "as often as needed"  When the fluid as seen in the sight glass becomes cloudy or discolored. it is usually an indication of the need for preventive maintenance.

Contaminated oil case

 Safety first.  PLEASE WEAR SAFETY GLASSES AND LATEX GLOVES. Change your fluid when the pump is warm and drain as much spent fluid out of the oil case by tilting the pump if possible. Turning the pump on for one or two seconds will force out additional spent fluid from the pump module.  You can also add some fresh fluid to the fill while draining to flow out particulate that remains at the bottom of the oil case. 

 Trapping, Inlet and Exhaust Filtering

Inlet Filtering and Trapping serves the purpose of keeping particulate, unwanted water vapor and solvents out of the pump.  Both solutions require preventive maintenance of their own and can be detrimental vs. beneficial if not monitored.  An example is the case whereby a cold trap warms and all of the frozen trapped material rushes into the inlet of the pump seizing it.  Exhaust or demisting filters serve the function of coalescing fluid and keeping the vapors out the exhaust extraction system or lab.  Keep in mind whatever enters the intake of the pump, ultimately leaves the exhaust and should be properly vented outside the lab in keeping with all regulatory agency rules and regulations.    

Other:

System Integrity

Two stage vacuum pumps are designed to reach ultimate vacuum in a relatively short period of time.  While pumping down, they normally expend some fluid out the exhaust.  Leaks caused by defective plumbing, hoses, o-rings etc. are detrimental to the performance and life span of your pump.  Replace all hoses found to be cracked with vacuum grade tubing. 

 Cooling and Air Circulation

Larger mechanical pumps flow cooling water through them, smaller ones require air circulation to keep the pump and motor within the acceptable operating range concerning temperature.  Many vacuum pumps are placed and operated in closed compartments especially in labs. Based on experience, they seem to survive but this is a case whereby clean fluid is essential for survival of the pump.