type	Gas transfer pump	brand	Jieyou	model	JZJH
material	cast iron	principle	vacuum pump	Drive Type	electric
Specifications	JZJPH(2H70A)ZJPH((2H30

The Roots slide valve vacuum unit is a vacuum unit composed of a regular Roots pump as the main pump and a slide valve vacuum pump as the front stage pump in series. Automatic opening and closing of Roots pump slide valve pump and automatic overload protection are achieved through vacuum relay or electric contact pressure gauge. The entire unit is installed on a rack, equipped with pipelines, valves, electrical control boxes, and cooling water pipe systems. The unit has a compact structure and is easy to use. According to the size and ultimate pressure of the vacuum system being evacuated, the nominal pumping speed ratio between the pumps of the vacuum unit is generally between 4:1 and 10:1. The former is more suitable for larger vacuum systems and long-term operation under lower inlet pressure or ultimate vacuum conditions than the latter. In order to prevent oil return when the slide valve pump stops, this series of units is equipped with an electromagnetic inflation valve on the inlet pipeline of the front stage. Its action is linked with the motor of the front stage pump. Before the slide valve pump stops, it inflates the pump port to ensure that the vacuum oil in the slide valve pump returns to the oil tank and prevent the vacuum system from being contaminated by vacuum oil.