Many cannabis professionals use the Edwards E2M28 Rotary Vane vacuum pump or a similar brand oil filled, rotary vane style vacuum pump when purging butane, propane and other condensable vapors. Here are a few recommendations from Edwards Vacuum to get optimal pump performance and increase the length of time between oil changes.
To pump condensable vapors
Use gas-ballast (open the gas-ballast control) when there is a high proportion of condensable vapors:
- Close the vacuum system isolation-valve.
- Turn the gas-ballast control counterclockwise to fully open. Run the pump for 30 minutes to warm the oil. Warm oil will help prevent vapor condensation in the pump.
- Open the vacuum system isolation-valve and continue to operate the pump with the gas-ballast control open.
- After you have pumped condensable vapors you can (if necessary) decontaminate the oil.
To decontaminate oil
The oil in the pump should be clear, however, if the oil is cloudy or discolored this means that it is contaminated with process vapors.
- Look at the condition of the oil in the oil sight-glass. If the oil is cloudy or discolored, close the vacuum system isolation-valve.
- Turn the gas-ballast control fully counterclockwise.
- Operate the pump until the oil is clear.
- Keep a supply of fresh vacuum pump oil on hand.
It is recommended that you decontaminate the oil before you shut down the pump. This will prevent damage to the pump by the contaminants in the oil.
Vacuum pumps are designed for unattended operation under the normal operating conditions. However, it is recommended that you check the pump at a regular interval of not more than 14 days. Be sure to check the pump more frequently if you pump high volumes of gas or if you operate the pump with the gas-ballast control open.
Single-phase motors are cooled by internal fans. These motors have a thermal overload device. When the motor is too hot, the thermal overload device switches off the pump. The thermal overload device has an automatic reset; when the motor cools down, the device resets and the motor will restart.