Patent ID: 7163025

Claim:
A vacuum regulating valve, comprising: a main valve with a relatively large size, the main valve is comprised of: a casing that defines therein a valve chamber extending along an axis of the main valve, and a main valve element operating unit that is separated from the casing by a partition wall; the casing includes: a first main port parallel along the axis of the main valve, and coupled with a vacuum vessel; a second main port substantially perpendicular to the axis of the main valve, and coupled with a vacuum pump; a main fluid passage defined by the main valve chamber, which forms a passageway between the first main port and the second main port; and a main valve element coupled with a tapered piece with a decreasing diameter on the first main port side, regulating pressure and vacuum environment of the first main port and the vacuum vessel; the main valve element operating unit includes: a cylindrical casing forming a cylindrical chamber, which includes a main piston coupled with a main valve stem that, in turn, is coupled with the main valve element, with the main valve stem extending in the valve chamber from the main valve element and through the partition wall and into the cylindrical chamber; the main piston operates to move the main valve element onto the main valve seat, where the main valve element substantially seals and isolates the first main port, the vacuum vessel, and content therein from the main fluid passage when the main valve element is in a closed position, urged against a main valve seat by a set of return springs; the main valve seat is formed at an outer periphery of an opening of the first main port; the main piston operates to move the main valve element away from the main valve seat, causing an evacuation of content from the first main port and the vacuum vessel by a negative pressure to permit fluid flow from the vacuum vessel into the first main port, and into main fluid passage and out by the vacuum pump; and a sub valve that has a relatively small size, is attached to an external side surface of the casing of the main valve, and comprises: a sub valve element operating unit that drives a sub valve stem to move a sub valve element onto and away from a sub valve seat; the sub valve element is moved to an open position before the main valve element is moved to an open position to commence an initial evacuation of the first main port and the vacuum vessel by initiating negative pressure to permit fluid flow from the vacuum vessel into a bypass passage; the sub valve element is moved to the closed position after the main valve element is moved to the closed position to commence positive pressure within the first main port and the vacuum vessel, preventing fluid flow from the vacuum vessel into the bypass passage; a first end of the bypass passage is opened into the first main port, a middle section of the bypass passage is coupled with the sub valve, and the second end of the bypass passage is opened into the main fluid passage, with the bypass passage bypassing the main valve seat.