Is the rotary vacuum pump removing hydrocarbons?
When the rotary vacuum pump operates at a limit pressure of less than 0.5 hPa, oil molecules will migrate toward the inlet for functional reasons.
During processing, mainly at high altitudes or in ultra-high vacuum, the presence of hydrocarbons is highly undesirable and unacceptable, damaging processes and equipment. This pollution can only be removed over time and at increased cost.
To avoid oil migration, molecular sieves, catalytic traps or cooling traps must be installed at the inlet of the rotary vacuum pump. Using a catalytic sieve, the copper catalyst is able to break down hydrocarbons into water and hydrogen and then pump them out. It is recommended that the used zeolite traps (zeolites) be regenerated by regular baking at approximately 250°C. To this end, manufacturers provide suitable heating elements as accessories. Catalytic traps can be regenerated by ventilation.
In the molecular flow state, the pump speed of the rotary vacuum pump will be reduced due to conductivity loss (resistance). So in the selection of pump size, for its specific purpose, be sure to take this factor into account. The same applies to the following filter. Please refer to manufacturer’s specifications for conductivity values (l/s) for different pressure ranges.
Rotary vane vacuum pump in organosilicon production plant of application
With the increasing demand of organosilicone at home and abroad and the improvement of organosilicone technology, in the process of its development, the demand for vacuum pump, the key equipment of hydrolyzate cracking process, is getting higher and higher. In order to meet these conditions, this requires the use of rotary vane vacuum pump.
The most common problems with vane pumps and how to avoid them
Dust in the process
Gas processing often produces particles or dust. In order to protect the vacuum pump from mechanical damage and extend the service life of the working fluid, it is necessary to install a dust filter at the inlet outlet. Depending on the application of the product, the dust filter has filter elements made of different materials, such as paper, polyester fiber, carbon fiber or oil filler (ring). A two-stage combination comprising a cyclone separator and a filter element may also be used for dust removal. Cyclones have the unique advantage of cooling hot molecules due to their rotational motion.
Mark the dimensions of inlet and exhaust pipes
The nominal diameter of the inlet and outlet is designed by the manufacturer according to the maximum pump speed of the vacuum pump. Therefore, it is critical that the nominal diameter of the inlet pipe and the vacuum pump conform, otherwise the pump speed will be seriously reduced due to the conductivity loss, especially in the range of molecular flow. The exhaust line should also be consistent with the nominal diameter of the pump. If the nominal size is too small or the gas flow is too large, the back pressure is unacceptable. In addition, noise levels can rise significantly.
If the exhaust line extends upwards, it should be siphon shaped at its lowest point so that the condensing steam rising in the line does not re-flow back into the pump. Siphons can be emptied through the bottom exit. In addition, in the exhaust pipe, the condensing separator can be installed 20-50 cm above the pump nozzle, so that the condensate can also be collected. It is not recommended to install the filter directly on the exhaust line of the vacuum pump, because directly connected, the heat of the pump body will be transferred to the condenser, resulting in reduced condensation effect.
As a result of the rotary vacuum pump compression operation, it is bound to release a certain amount of heat, so it must provide enough ventilation, if necessary, it is best to install another fan to ensure its normal cooling. This is especially suitable for pumps installed in equipment or sound absorption hood. If ventilation requirements are not met, the equipment may overheat and damage the pump.
Many of these instructions also apply to other types of vacuum pumps, such as roots and dry pumps.