If you are a home mechanic trying to keep your air conditioning system in check, or if you are a professional automotive mechanic or air conditioning technician, then you know that an air conditioning pump is an important tool in your tool shed. In this short review we will go over the advantages and disadvantages of two types of pumps frequently used to create vacuum in air conditioning systems, a Venturi vacuum pump or air pump and a Rotating vane vacuum pump or a spinning pump. By considering their pros and cons you should better be able to decide which pump to get for your next air conditioning service application.
Venturi pumps achieve vacuum on the principle of Venturi. This states that, when a liquid or a gas is sent through a pipe whose diameter is progressively reduced as the liquid goes further down the pipe, the average velocity of liquid or gas molecules increases and the pressure of the liquid or gas is reduced. At the narrowest point along the pipe, the vacuum is thereby generated.
The only real advantage of Venturi type pumps is their price. These “aspirator pumps” are the least expensive of all available pumps. On the other hand, the vacuum obtained is neither high nor is it obtained in the fastest possible manner.
Rotating vane vacuum pump
A rotating vane pump or rotary vane pump operates by having a central rotor positioned off-axis inside of a cylinder. The vanes extending outside of the rotor create an expanding volume on the incoming end and the shrinking volume on the outgoing end. As the rotor rotates, the volume on the incoming end is increased, producing vacuum. The gas pulled out of the system is then compressed and released to the outside air through the outgoing end in the second phase of a single rotator turn.
As rotary vane pumps are based on the efficient electromagnetic motor, rotary vane pumps are efficient, fast, quiet, and can achieve higher vacuum than the Venturi type pumps. Depending on the size of the cylinder and rotor, the rotating vane pumps can pull more volume per minute too, therefore achieving higher vacuum faster.
The only downsides of the rotating vane pumps is that they require special pump oil to operate smoothly and achieve maximum vacuums, and the price – they are a bit higher priced than the simpler Venturi type pumps.