Liquid ring vacuum pump selection

Determination of pump type

Pump type is mainly required by the work of air volume, vacuum or exhaust pressure.
When the pump works, the following two aspects should be paid attention to:
As far as possible, it is required to operate in the efficient zone, that is, in the critical vacuum or critical exhaust pressure area.
Avoid operating near maximum vacuum or exhaust pressure. Running in this area, not only the efficiency is very low, but also the work is very unstable, easy to produce vibration and noise. For the vacuum pump with higher vacuum degree, cavitation phenomenon will often occur when operating in this area. The obvious sign of this phenomenon is the noise and vibration inside the pump.
Cavitation will lead to pump body, impeller and other parts of the damage, so that the pump can not work.
According to the above principles, when the pump required vacuum or gas pressure is not high, can be preferred in the single-stage pump. If the vacuum or exhaust pressure is high, the single-stage pump often can not meet, or, the pump is required in the case of high vacuum is still a large amount of air, that is, the performance curve in the higher vacuum is flat, can choose two-stage pump.
If the vacuum degree is above -710mmhg, liquid ring-air pump or liquid ring-roots vacuum unit can be selected as the vacuum pumping device.

According to the air volume required by the system to select the vacuum pump

After the initial selection of the type of pump, for the vacuum pump, but also according to the amount of air required by the system to choose the type of pump.
The vacuum pump pumping speed selection and pumping time calculation can refer to our company website vacuum calculation formula.
After the initial selection of the type of pump, for the vacuum pump, but also according to the amount of air required by the system to choose the type of pump.
The vacuum pump pumping speed selection and pumping time calculation can refer to our company website vacuum calculation formula.

In the face of various types of water-ring vacuum pumps and compressors, we specially collect their respective characteristics as follows for the convenience of user selection

Code	main feature	Ultimate vacuum mmHg	Working vacuum mmHg	Pumping speed range M3/min	Sealed form
SK	The domestic design of single-stage liquid ring vacuum pump is simple in structure and convenient in maintenance. At present, the low-end liquid ring vacuum pump will gradually be replaced by 2BV and 2BE series products.	-700	-300~-650	0.15~120	Packing, Machinery Seal
2SK	The domestic design of the two-stage liquid ring vacuum pump is equivalent to the use of two SK liquid ring pumps in series. The single-stage liquid ring pump has the characteristics of high vacuum and high pumping speed under high vacuum. At present, the low-end liquid ring vacuum pump will gradually be replaced by 2BV and 2BE series products.	-735	-300~-700	1.5~30	Packing, Machinery Seal
2BV	Adopting Siemens advanced technology, the machine pump is coaxial, compact structure, high efficiency, high vacuum and stable performance, it will gradually replace the liquid 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 liquid ring vacuum pump of SK, 2SK series 6~120m3/min pumping speed.	-735 -640	-300~-700 -300~-600	5~120	Packing, Machinery Seal
2BE3	Adopting advanced technology of Siemens, high efficiency, high vacuum and stable performance, it will gradually replace the SK series 80~600m3/min pumping liquid ring vacuum pump.	-610	0~-600	80~600	Packing, Machinery Seal
SZ	5Soviet technology in the 1970s, 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 liquid ring pump.	-600	-300~-550	0.33~0.66	Packing

 

Performance impact of liquid ring vacuum pump

Affected by the water temperature on the performance of liquid ring vacuum pumps, and liquid ring vacuum pump performance curves are obtained under the condition of the water temperature of 15 ℃, so in the actual selection of liquid ring vacuum pump when dealing with extraction rate of liquid ring vacuum pump.
The actual pumping speed of liquid ring pump can be calculated according to Qt=Q15K, K = (p1-pt)/(p1-p15), where:
Qt – when the water temperature of t ℃ after gas m/min Q15 – when the water temperature of 15 ℃ after gas m/min
P1 – liquid ring pump suction pressure mmHg Pt – the saturated vapor pressure of water temperature of t ℃ mmHg
P15 – the saturated vapor pressure of water temperature of 15 ℃ mmHg K – volume correction coefficient

The K value of liquid ring vacuum pump at various temperatures and suction pressures can be referred to the following table

 

Water temperature °C	Suction pressure mmHg
	25	30	35	40	50	60	80	100	120	150	200	250	300	400	500	600	760
0	1.685	1.486	1.376	1.307	1.225	1.177	1.124	1.096	1.078	1.061	1.045	1.035	1.029	1.022	1.017	1.014	1.011
2	1.627	1.445	1.345	1.281	1.206	1.162	1.114	1.088	1.071	1.056	1.041	1.032	1.027	1.02	1.016	1.013	1.01
4	1.561	1.398	1.308	1.252	1.184	1.145	1.102	1.079	1.064	1.05	1.037	1.029	1.024	1.018	1.014	1.012	1.009
6	1.487	1.345	1.268	1.218	1.16	1.126	1.088	1.068	1.055	1.043	1.032	1.025	1.021	1.015	1.012	1.01	1.008
8	1.403	1.286	1.221	1.181	1.132	1.104	1.073	1.056	1.046	1.036	1.026	1.021	1.017	1.013	1.01	1.008	1.007
10	1.308	1.219	1.169	1.138	1.101	1.08	1.056	1.043	1.035	1.027	1.02	1.016	1.013	1.01	1.008	1.006	1.005
12	1.201	1.143	1.111	1.09	1.066	1.052	1.037	1.028	1.023	1.018	1.013	1.01	1.009	1.006	1.005	1.004	1.003
14	1.081	1.057	1.045	1.036	1.027	1.021	1.015	1.011	1.009	1.007	1.005	1.004	1.003	1.003	1.002	1.002	1.001
16	0.946	0.962	0.97	0.976	0.982	0.986	0.99	0.992	0.994	0.995	0.996	0.997	0.998	0.998	0.999	0.999	0.999
18	0.795	0.855	0.888	0.908	0.933	0.947	0.963	0.971	0.977	0.982	0.987	0.989	0.991	0.994	0.995	0.996	0.997
20	0.627	0.735	0.795	0.833	0.878	0.904	0.932	0.948	0.958	0.967	0.976	0.981	0.984	0.988	0.991	0.992	0.994
21	0.536	0.671	0.745	0.792	0.848	0.88	0.916	0.935	0.947	0.959	0.97	0.976	0.98	0.985	0.988	0.99	0.992
22	0.439	0.602	0.692	0.748	0.816	0.855	0.898	0.922	0.936	0.95	0.963	0.971	0.976	0.982	0.986	0.988	0.991
23	0.337	0.53	0.636	0.703	0.783	0.829	0.88	0.907	0.925	0.941	0.957	0.966	0.972	0.979	0.983	0.986	0.989
24	0.23	0.454	0.577	0.655	0.747	0.801	0.86	0.892	0.912	0.932	0.95	0.96	0.967	0.976	0.981	0.984	0.987
25	0.117	0.374	0.515	0.604	0.71	0.772	0.84	0.876	0.899	0.921	0.942	0.955	0.962	0.972	0.978	0.982	0.986
26	0	0.289	0.449	0.55	0.671	0.741	0.818	0.86	0.886	0.911	0.935	0.948	0.957	0.968	0.975	0.979	0.984
27	－	0.2	0.38	0.494	0.63	0.708	0.795	0.842	0.872	0.9	0.926	0.942	0.952	0.964	0.972	0.977	0.982
28	－	0.106	0.308	0.435	0.587	0.674	0.771	0.824	0.857	0.888	0.918	0.935	0.946	0.96	0.968	0.974	0.979
29	－	0.008	0.231	0.372	0.541	0.638	0.746	0.804	0.841	0.876	0.909	0.928	0.941	0.956	0.965	0.971	0.977
30	－	－	0.151	0.307	0.493	0.601	0.719	0.784	0.824	0.863	0.899	0.921	0.934	0.951	0.961	0.968	0.975
31	－	－	0.066	0.238	0.443	0.561	0.692	0.762	0.807	0.849	0.889	0.913	0.928	0.946	0.957	0.965	0.972
32	－	－	－	0.166	0.39	0.519	0.662	0.74	0.788	0.835	0.879	0.904	0.921	0.941	0.953	0.961	0.97
33	－	－	－	0.089	0.334	0.475	0.631	0.716	0.769	0.819	0.868	0.896	0.914	0.936	0.949	0.958	0.967
34	－	－	－	0.01	0.276	0.429	0.599	0.691	0.749	0.804	0.856	0.886	0.906	0.93	0.945	0.954	0.964
35	－	－	－	－	0.215	0.381	0.565	0.665	0.727	0.787	0.844	0.877	0.898	0.925	0.94	0.95	0.961
36	－	－	－	－	0.15	0.33	0.53	0.637	0.705	0.77	0.831	0.867	0.89	0.918	0.935	0.946	0.958
38	－	－	－	－	0.012	0.221	0.453	0.579	0.657	0.732	0.804	0.845	0.872	0.905	0.925	0.937	0.951
40	－	－	－	－	－	0.102	0.369	0.514	0.605	0.691	0.774	0.821	0.852	0.891	0.913	0.928	0.943
42	－	－	－	－	－	－	0.277	0.443	0.547	0.646	0.74	0.795	0.831	0.875	0.9	0.917	0.935
45	－	－	－	－	－	－	0.122	0.324	0.45	0.57	0.685	0.751	0.795	0.848	0.879	0.9	0.921
50	－	－	－	－	－	－	－	0.086	0.257	0.419	0.574	0.664	0.723	0.794	0.836	0.864	0.893
55	－	－	－	－	－	－	－	－	0.018	0.233	0.438	0.556	0.634	0.728	0.784	0.821	0.859
60	－	－	－	－	－	－	－	－	－	0.004	0.27	0.424	0.524	0.647	0.72	0.767	0.817
70	－	－	－	－	－	－	－	－	－	－	-0.18	0.068	0.23	0.429	0.546	0.624	0.704
80	－	－	－	－	－	－	－	－	－	－	－	－	－	0.115	0.297	0.417	0.542
100	－	－	－	－	－	－	－	－	－	－	－	－	－	－	－	－	0

 

Liquid ring vacuum pump picture display

 

(The article comes from the Internet. If reprinting is not allowed, please contact our company to delete it.)