JZJ2S series Package Units
JZJ2S series Roots water ring vacuum unit is composed
of one ZJ Roots pump as the main work pump,and two grades water ring vacuum
pump or Roots +water ring vacuum unit as a fore pump. Except for being
used for pumping the general gas, and also other gases that contains moisture
or dust. Comparing with the general machinery vacuum pump, the Roots unit
is not afraid of the oil pollution, the moisture and dust. And comparing
with the water ring vacuum pump, it has the higher vacuum and bigger suction
capacity when operating in the high vacuum.
The Roots water ring vacuum unit are extensively used in chemical industry,
electronics, machinery, pharmacy, foodstuff etc..
When to use the oil as operating liquid，it can increase the Roots vacuum
unit's limited vacuum effectively（seeing the parameter table）.The Roots
oil ring vacuum unit adopts the closing circulation system, and it can
reduce the pollution and the water cost. The Roots pump and oil ring vacuum
pump unit is extensively used in the technology process such as soaking
in the vacuum, vacuum dry and gas vacuum wiping off etc.
Because the JZJ2S series units are adopted the 2SK series pumps, the whole
efficiency is lower than the JZJ2B series. And the 2SK series pumps' structure
is very complicated and maintainance is not convenient, the JZJ2S series
units have been replaced by the JZJ2B series step by step.
The selection of Roots water ring vacuum units：
Normally, to choose the water ring vacuum pump as the fore pump is more advantaged than to choose others for the water ring vacuum pump can pump plentiful coagulable steam. And this advantage is more obviously when to use the gas-down and oil seal mechanical vacuum pump as the fore pump but it is low ability of pumping the coagulable steam, or to use the solvent as the operating liquid but making the oil bad, or the system are not allowed the pollution. Furthermore, to choose the Roots units, it is necessary to make the working vacuum is five or ten times of the limited vacuum in order to achieve the Roots units' best performance. i.e. working vacuum≥limited vacuum ×（5~10）.
Several category of the Roots pump and water ring vacuum pump units:
Roots pump＋water ring vacuum pump：The function of the
water ring vacuum pump is to form the pre-vacuum for the Roots pump.
Roots pump＋Roots pump＋water ring vacuum pump：To use one set Roots pump,
especially connecting with the water ring vacuum pump, the limited vacuum
of the whole unit may much lower for its usage scope are restricted. But
to use two sets Roots pumps in series and to connect them with the water
ring vacuum pump can improve the whole limited vacuum largely.
Roots pump＋Roots pump＋Roots pump＋water ring vacuum pump：If the two Roots
pumps and water ring vacuum pump unit are still dissatisfied the vacuum
requirements, it can add another Roots pump. These series Roots units
are extensively used in some high vacuum technics of the vacuum freezing
or dry process.
Type denotation
For example：J Z J 2 B 1 5 0 － 2 . 1
J-denotes the first letter in the unit
ZJ-denotes the ZJ series Roots vacuum pumps
2B-denotes the fore pump using the 2BV/2BE series water(or liquid)
ring vacuum pumps
（if "2S", denotes the fore pump using the 2SK series water
(or liquid) ring vacuum pumps
150-denotes the suction speed of the main pump (refers the Roots
pump) L/s
2.1-denotes the suction speed ratio of the pumps in the unit
(i.e. the suction speed ratio of the main pump and the second pump
is 2，and the suction speed ratio of the second pump and the fore pump
is 1.)