The pump consists of two figure “8” shaped rotors and two semicircular pump houses. The rotors rotate synchronously in opposite directions and high speeding. The pump cannot be used singly; it must be used as boosters combined with a backing pump such as a rotary piston or a rotary vane vacuum pump, or a liquid ring vacuum pump. These vacuum systems can get higher vacuum, a stable, fairly high pumping speed can be gained in effective pressure range. The backing pump decides the ultimate pressure of roots pump. The data of the list is lowest ultimate pressure with the standard equipment (equipped double stage oil machine vacuum pump). The Roots pumps are widely used in vacuum moulding, vacuum smelting, vacuum gas pumping, vacuum coating industry, vacuum distilling and vacuum drying of chemical and pharmaceutical industry etc. The pump is insensitive to a little dust.
Merit:
1. The lack of reciprocating parts allows a perfect dynamic balancing, because the rotors is processed by numerical control machine tool and balanced carefully. It has perfect geometry symmetry. There is certain clearance between the two rotors. The pump house and end-cover is processed by especial machine tool. It has high precision. So the pump own feature of stable operation, low noise, low vibration and high ultimate pressure.
2. The robust drive of ump and operating parts balanced carefully permit that the pump be stably operated continuously under the condition of high different pressure.?
3.They can be started quickly, and in short time ultimate pressure is reached
4. Lubrication is unnecessary as there is no contact between rotors, rotor and house, that avoid oil vapor from polluting vacuum system.
5. Good reliability characteristic. Their inherent overflow valve play auto-protective role.
6. Compact structure, low footprint design. There are three gas outlet ports that are in left, right and under pump house. It is convenient for consumer installing.

 

ZJ、ZJP pum main perfomance-parameter table

型號	Ultimate pressure(Pa)		pumping speed(L/S)	maximum permissible Different pressure (HPa)	lnlet & outlet dimensions (mm)		Power (kw)	Max Compression ratio with zero throughput	Weight(Kg)
	配用雙級油封 機械真空泵	配用單級油封 機械真空泵			lnlet	outlet
ZJP-70	≤2x10-2	≤1x10-1	70	100	80	50	1.5	≥35	100
ZJP-150			150	80	100	100	2.2/3	≥40	220
ZJP-300			300	80	150	150	4	≥40	300
ZJP-600			600	50	200	200	5.5/7.5	≥45	575
ZJP-1200			1200	50	250	200	11/15	≥50	860
ZJP-2500			2500	30	320	250	18.5/22	≥50	1480
ZJ-30			30	100	50	40	0.75	≥30	55
ZJ-70			70	100	80	50	1.5	≥35	90
ZJ-150			150	80	100	100	2.2/3	≥40	210
ZJ-300			300	80	150	150	4	≥40	285
ZJ-600			600	50	200	200	5.5/7.5	≥45	550
ZJ-2500			2500	30	320	250	18.5/22	≥50	1480
ZJ-5000			5000	30	400	320	37/45	≥55	3400

Model	A	A1	A2	A3	B	B1	B2	B3	H	H1	H2	H3	D	D1	D2	d	d1	d2	d3	d4	d5	m	n	p	e	f	g	k	A4	B4	H4
ZJP150B	115	57.5	152	675	320	360	245	190	385	205	30	95	100	145	170	100	145	170	80	125	145	4	4	4	10	10	10	18	950	495	415
ZJP150BJ	580	197	620	675	320	370	245	190	475	295	120	185	100	145	170	100	145	170	80	125	145	4	4	4	10	10	10	18	950	495	505
ZJP300B	225	112.5	314	775	320	360	285	185	440	215	25	130	150	195	220	150	195	220	100	145	170	8	8	8	10	10	8	18	1125	520	440
ZJP300BJ	740	277	780	775	320	380	285	185	525	300	110	215	150	195	220	100	195	220	100	145	170	8	8	8	10	10	8	18	1125	705	470
ZJP600B	170	85	250	896	500	550	375	285	610	320	40	172	200	250	275	200	250	275	160	200	225	8	8	8	10	10	10	18	1270	705	650
ZJP600BJ	760	277.5	815	896	480	550	375	285	673	383	103	235	200	250	275	160	250	275	160	200	225	8	8	8	10	10	10	24	1270	800	713
ZJP1200B	948	316	1000	1225	520	630	425		675	385	65	250	250	310	335	200	260	285	200	260	285	12	12	12	10	10	10	24	1720	800	715
ZJP1200C	380	190	490	1170	480	540	425		590	300	30	165	250	310	335	200	260	285	200	260	285	12	12	12	10	10	10	24	1666	800	635
ZJP1200CJ	948	316	1000	1170	520	590	425		675	385	115	250	250	310	335	200	260	285	200	260	285	12	12	12	12	10	10	26	1666	800	720
ZJP2500	735	367.5	855	1333.5	630	720	460		665	390	40	220	320	395	425	250	310	335	320	395	425	12	12	12	12	10	12	26	1900	800	800