VACUUM PUMP FREQUENTLY ASKED QUESTIONS Why is it so important to change the oil often in my vacuum pump? The proper oil in a vacuum pump acts as a blotter and absorbs all of the moisture and non-condensables. As the oil becomes saturated with these contaminants, the efficiency of the pump is dramatically reduced. Maintaining clean oil in the pump ensures that the pump will operate at peak efficiency and prolong its life. Why is it important to change my oil when the pump is hot? As the pump cools, the moisture and contaminates start to separate in the pump and when drained, the contaminants cling to the walls of the pump. When you refill the pump with new oil, those contaminants will mix in with the new oil as the pump warms up resulting in the new oil quickly becoming contaminated. If I am always pulling a vacuum on clean, dry systems, is there a way to check my oil in the pump to see if it is contaminated and not have to change it so frequently? It is recommended that a micron gauge be attached directly to the pump and should pull to 50 microns or lower if the oil is clean. If the micron gauge does not pull to 50 microns, it is an indication that the oil is becoming contaminnated and should be changed. Other than pulling air out of the system, how does my vacuum pump get rid of the moisture in the system? Most two stage vacuum pumps will go low enough in vacuum and reduce the atmospheric pressure within the system, thus allowing boiling of the moisture at a lower temperature. Once the moisture is in a vapor form, it is readily removed by the pump. What is a gas ballast and how do I use it? On the initial pull of vacuum on a system, the gas ballast is open allowing the initial volume of air in the system to bypass the oil so as to not contaminate the oil immediately. When the pump starts to quiet down, close the gas ballast and the pump will start reducing atmospheric pressure in the system to boil the moisture and non-condensables. What is a blank-off valve? The blank-off valve acts no different than a water valve. Open it, and with the pump running you will get your desired vacuum. Close it, and with the pump running there is no vacuum. If I use a larger CFM pump, will I be able to pull a vacuum on a system faster? In most cases NO. Using a vacuum pump on air conditioning systems from 1 ton to 10 tons, you will not see the difference between a 3 CFM pump and a 10 CFM pump. For example, if you put a pump on a system and you notice within 2 minutes the pump quiets down and you cannot really feel any air leaving the exhaust. This means that there is no more CFM left in the system and you are now working with molecules. Thus, at this point if you replaced a 3 CFM pump with a 10 CFM pump, there is no change in vacuum or time. What is a micron? There are 25,400 microns in an inch. Therefore, with a compound gauge reading 0 inches to 30 inches, there are 762,000 microns. What is a micron? There are 25,400 microns in an inch. Therefore, with a compound gauge reading 0 inches to 30 inches, there are 762,000 microns. Why does the micron gauge slowly fall back and then start to hold after pulling a vacuum and blanking-off? The reason for this is there is equalization within the system. If you pull a vacuum lower, it will then fall back at a shorter range and hold. Why do I need to check the oil level when the pump is running? The reason for this is that if the vacuum is not broken before pumps are shut down the oil in the cover will seek the vacuum still in the cartridge and intake chamber. Then the oil level will drop in the sight glass and give the appearance of a low oil level. Then if the pump is refilled to the oil level line and the pump started, the oil that got sucked back into the cartridge and intake chamber will be kicked back into the cover and now you’ll be over filled and the oil will shoot out the handle (exhaust port). As the pump cools, the moisture and contaminates start to separate in the pump and when drained, the contaminants cling to the walls of the pump. When you refill the pump with new oil, those contaminants will mix in with the new oil as the pump warms up resulting in the new oil quickly becoming contaminated. If I am always pulling a vacuum on clean, dry t rid of the moisture in the systeost two stage vacuum pumps will go low enough in vacuum and reduce the atmospheric pressure within
Posted on: Tue, 18 Mar 2014 17:06:49 +0000
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