Overheating in the outlet pipeline of the Roots vacuum pump
Thread Content
The pumping capacity of the primary pump is 700 cubic feet per hour, while that of the Roots pump is 35 cubic feet per minute. The Roots pump operates at variable frequency, with the frequency usually set at 50%. Under normal conditions, the vacuum level reaches 985, but the outlet pipe of the pump heats up, and the vacuum level drops to below 960. What’s going on?
It depends on the operating conditions. The vacuum pump itself has poor cooling performance, and the temperature of the gas flowing in is relatively high.
The intake pipeline is cooled by chilled water, so the intake temperature does not exceed 10 degrees
The temperature of the exhaust pipe of the vacuum pump is high – exactly how high? Is it within the operating temperature range of the vacuum pump? As long as it is within that range, there is no problem. It is normal for the vacuum level to decrease when the temperature is high.
1. Is there any issue with poor exhaust flow at the outlet? 2. Is the circulation fluid of the vacuum pump itself flowing properly, or is there any blockage?
This post was last edited by symc on 2016-11-21 at 17:04. The key is to determine what type of pump is used as the preceding pump; however, in 99% of cases like yours, it’s due to an excessive compression ratio… As an aside, 99.9% of domestic rotary pump manufacturers encounter similar problems, as they fail to fully understand the design techniques related to rotary pumps and other preceding pumps. Creating a pump only requires a single drawing, but to use it effectively one needs to understand the relevant engineering processes. What domestic manufacturers lack is an understanding of these engineering techniques. As a result, even though they may produce the pump using the same drawings as those used by foreign manufacturers, the entire system ends up functioning poorly, which gives users the impression that domestic products are of poor quality – though this isn’t entirely true； Of course, many imported manufacturers do the same, but the Chinese have always tended to admire foreign things and show favoritism toward them; even when problems arise, they won’t attribute them to the foreign party!
If the pump’s suction temperature is around 10 degrees and the discharge temperature is around 30 degrees, it can generally be assumed that there is a problem with the equipment. 1. The selection and ratio of equipment are inappropriate. A Roots vacuum pump was selected; it is a three-blade Roots pump. A problem associated with this type of pump is that although its pumping capacity is good, the temperature generated within the pump itself is relatively high. It is recommended to install a condenser to cool the pump body with cold air.
For ordinary Roots pumps operating in a pressure range of 1.5–4 kPaabs (960–985), when the compression ratio exceeds 3 (35 m3/min = 2100 m3/h; 700 m3/h should still represent the nominal pumping volume), the pump will definitely overheat due to overload! ! The primary pump is likely to be a water ring pump; it is necessary to increase the pumping capacity of this primary pump in order to reduce the pressure at its inlet
It is recommended to replace the forepump; the pumping capacity of the forepump is not suitable for use with the Roots pump, and only by increasing the pumping capacity of the forepump can this issue be resolved