Types and characteristics of water ring vacuum pumps
First, the type of water ring vacuum pump is determined After the initial selection of the pump type, the vacuum pump is also selected according to the amount of gas required by the system. Code main feature Ultimate vacuum Working vacuum Pumping speed range Sealed form Sk The domestic design of single-stage water ring vacuum pump is simple in structure and convenient in maintenance. At present, the domestic mainstream low vacuum water ring vacuum pump. -700 -300~-650 0.15~120 Packing, 2sk The domestic design of the two-stage water ring vacuum pump is equivalent to the use of two SK water ring pumps in series. The single-stage water ring pump has the characteristics of high vacuum and high pumping speed under high vacuum. At present, the domestic mainstream water ring vacuum pump. -735 -300~-700 1.5~30 Packing, 2BV Adopting Siemens advanced technology, the machine pump is coaxial, compact structure, high efficiency, high vacuum and stable performance, it will gradually replace the water ring vacuum pump of SK~2SK series 0.4~6m3/min pumping speed. -735 -300~-700 0.45~8.33 Machinery Seal 2BE1 Adopting advanced technology of Siemens, high efficiency, high vacuum and stable performance, it will gradually replace the water ring vacuum pump of SK, 2SK series 6~120m3/min pumping speed. -735 -300~-700 5~400 Packing, SZ Soviet technology in the 1950s, low efficiency, high energy consumption, was eliminated in the early 1980s, mainly used by old users. -640~-700 -300~-650 1.5~27 Packing SZB Soviet technology in the 1950s, low efficiency, high energy consumption, has been eliminated in the early 1980s, mainly used in pump water diversion, has been replaced by SK series water ring pump. -600 -300~-550 0.33~0.66 Packing 2SY Mainly used in water ring compressors, the maximum exhaust pressure is 0.6MPa - - 6~30 Machinery Seal 2YK The structure is basically the same as that of the 2SK series, and the pumped medium can be used as the working fluid, and the ultimate vacuum varies with the saturated vapor pressure of the pumped medium. The ultimate vacuum in the table is the ultimate vacuum when the working medium is transformer oil. -755 -300~-720 1.5~30 Machinery Seal
The type of water ring vacuum pump is mainly determined by the amount of gas, vacuum or exhaust pressure required for operation.
When the water ring vacuum pump is working, the following two aspects should be noted: it is requested to operate in the high efficiency zone as much as possible, that is, in the region of critical vacuum or critical exhaust pressure. It should be prevented from operating at the maximum vacuum or maximum exhaust pressure. Operating in this area is not only extremely inefficient, but also unstable in operation and prone to vibration and noise. With regard to vacuum pumps with higher vacuum, it is often the case that cavitation occurs during operation in this area. The obvious sign of this phenomenon is noise and vibration in the pump. Cavitation can cause damage to parts such as the pump body and impeller, resulting in the pump not working.
According to the above criteria, when the vacuum degree or gas pressure required by the water ring type vacuum pump is not high, it can be preferentially selected in the single stage pump. If the vacuum or exhaust pressure is high, the single-stage pump is often not satisfied, or the pump is required to have a large volume under the condition of higher vacuum, that is, the requested performance curve is flat at a higher vacuum, and two can be used. Stage pump. If the vacuum is requested to be above -710mmHg, an optional water ring-atmosphere pump or water ring-Roots vacuum unit is used for vacuum installation.
If it is only used as a vacuum pump, it is better to use a single-acting pump. Due to the simple structure of the single-acting pump, it is easy to manufacture and maintain, and it has good anti-cavitation under high vacuum conditions.
If only a large-capacity compactor is used, it is more suitable to use a double-acting pump. Due to the large volume, small volume and light weight of the double-acting pump, the radial force can be automatically balanced, the shaft is not prone to fatigue and breakage, and the service life of the pump is long.
Second, select the vacuum pump according to the amount of gas required by the system
Third, in the face of various types of water ring vacuum pumps and squeezing machines, we have collected their respective characteristics as follows to facilitate user selection:
mmHg
mmHg
M3/min
Machinery Seal
Machinery Seal
-640
-300~-600
Machinery Seal