Vacuum pump system with light gas pumping and leak detection apparatus comprising the same

Patent metadata

Field	Value
Publication number	US-2016356273-A1
Application number	US-201514732637-A
Country	US
Kind code	A1
Filing date	Jun 5, 2015
Priority date	Jun 5, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A rough vacuum pump system includes a primary vacuum pump and a secondary vacuum pump. The primary vacuum pump is an oil-free positive displacement pump, and has an inlet opening, an outlet opening, a compression stage between the inlet and outlet openings, and an intermediate gas passageway that connects to a gas flow path running through the compression stage. The secondary vacuum pump is connected to the intermediate gas passageway of the primary vacuum pump. The compression ratio of the primary and secondary vacuum pumps operating in combination is greater than that of the compression ratio of either of the primary and secondary vacuum pumps operating individually. A vacuum apparatus includes a tracer gas detector connected to an inlet of the primary vacuum pump.

First claim

What is claimed is:

1 . A rough vacuum pump system comprising:
a primary vacuum pump having an inlet opening, an outlet opening, a compression mechanism including a compression stage constituted by discrete pockets of compression that are sealed from each other and are interposed between the inlet opening and the outlet opening, and an intermediate gas passageway having first and second ends, and a secondary vacuum pump having an inlet at which the secondary vacuum pump is connected to the primary vacuum pump at the first end of the intermediate gas passageway of the primary vacuum pump, and wherein the primary vacuum pump is an oil-free positive displacement pump, the pockets constituting the compression stage of the primary vacuum pump include an inlet pocket at which fluid is taken into the compression stage, and an outlet pocket from which fluid is discharged from the compression stage, the second end of the gas passageway of the primary vacuum pump is directly connected to a gas flow path of the primary vacuum pump that starts at the inlet opening, runs through the compression stage and ends at the outlet opening such that the secondary vacuum pump is operable to draw gas out of the compression stage of the primary vacuum pump at a location upstream of the outlet opening of the primary vacuum pump, and the compression ratio of the primary and secondary vacuum pumps operating in combination is greater than that of the compression ratio of either of the primary and secondary vacuum pumps operating individually.

2 . The system as claimed in claim 1 , further comprising a directional control valve disposed in-line between the intermediate gas passageway and the secondary vacuum pump.

3 . The system as claimed in claim 2 , wherein the valve is a two position directional flow control valve that is movable between a first position at which the valve allows the flow of gas to the secondary vacuum pump from the primary vacuum pump via the intermediate gas passageway, and a second position at which the valve blocks the flow of gas to the secondary vacuum pump from the primary vacuum pump via the intermediate gas passageway, and
further comprising a control system operatively connected to the secondary vacuum pump and to the valve and configured to turn the secondary vacuum pump off when the valve is in the second position thereof.

4 . The system as claimed in claim 2 , wherein the directional control valve has a first port at which the valve is connected to the intermediate gas passageway, a second port at which the valve is connected to the secondary vacuum pump, and a ballast gas third port, and
the valve is movable between a first position at which the valve allows the flow of gas to the secondary vacuum pump from the primary vacuum pump via the intermediate gas passageway while closing fluid communication between the intermediate gas passageway and the third port, and a second position at which the valve allows the flow of gas to the primary vacuum pump via the third port and intermediate gas passageway while closing fluid communication between the primary and secondary vacuum pumps via the intermediate gas passageway.

5 . The system as claimed in claim 1 , wherein the compression ratio of the primary and secondary vacuum pumps operating in combination to pump a gas whose density is less than that of air is greater than that of the compression ratio of either of the primary and secondary vacuum pumps operating to pump the gas alone.

6 . Vacuum apparatus comprising a rough vacuum pumping system as claimed in claim 1 , and a tracer gas detector that detects a tracer gas, the tracer gas detector being connected to the primary vacuum pump at an inlet of the primary vacuum pump defining the inlet opening.

7 . Vacuum apparatus as claimed in claim 6 , wherein the tracer gas detector comprises a mass spectrometer, Penning cell, magnetron, or gas-consuming vacuum gauge.

8 . Vacuum apparatus as claimed in claim 6 , wherein the compression ratio of the primary and secondary vacuum pumps operating in combination to pump the tracer gas is greater than that of the compression ratio of either of the primary and secondary vacuum pumps operating to pump the tracer gas alone.

9 . A rough vacuum pump system comprising:
a dry vacuum scroll pump defining an inlet opening, an outlet opening, and an intermediate gas passageway having first and second ends, and comprising a stationary scroll blade, an orbiting scroll blade nested with the stationary scroll blade so as to delimit therewith a series of pockets constituting a compression stage of the scroll pump, and an exhaust check valve disposed over the outlet opening; and a secondary vacuum pump having an inlet at which the secondary vacuum pump is connected to the vacuum scroll pump at the first end of the intermediate gas passageway of the vacuum scroll pump, and wherein the second end of the gas passageway of the vacuum scroll pump is directly connected to a gas flow path of the vacuum scroll pump that starts at the inlet opening, runs through the compression stage and ends at the check valve such that the secondary vacuum pump is operable to draw gas out of the compression stage of the vacuum scroll pump at a location upstream of the exhaust check valve, and the compression ratio of the vacuum scroll pump and secondary vacuum pump operating in combination is greater than that of the compression ratio of either of the vacuum scroll pump or secondary vacuum pump operating individually.

10 . The system as claimed in claim 9 , further comprising a directional control valve disposed in-line between the intermediate gas passageway and the secondary vacuum pump.

11 . The system as claimed in claim 10 , wherein the valve is a two position directional flow control valve that is movable between a first position at which the valve allows the flow of gas to the secondary vacuum pump from the vacuum scroll pump via the intermediate gas passageway, and a second position at which the valve blocks the flow of gas to the secondary vacuum pump from the vacuum scroll pump via the intermediate gas passageway, and
further comprising a control system operatively connected to the secondary vacuum pump and to the valve and configured to turn the secondary vacuum pump off when the valve is in the second position thereof.

12 . The system as claimed in claim 10 , wherein the directional control valve has a first port at which the valve is connected to the intermediate gas passageway, a second port at which the valve is connected to the secondary vacuum pump, and a ballast gas third port, and
the valve is movable between a first position at which the valve allows the flow of gas to the secondary vacuum pump from the vacuum scroll pump via the intermediate gas passageway while closing fluid communication between the intermediate gas passageway and the third port, and a second position at which the valve allows the flow of gas to the vacuum scroll pump via the third port and intermediate gas passageway while closing fluid communication between the vacuum scroll pump and the secondary vacuum pump via the intermediate gas passageway.

13 . Vacuum apparatus comprising a rough vacuum pumping system as claimed in claim 9 , and a tracer gas detector that detects a tracer gas, the tracer gas detector being connected to the vacuum scroll pump at an inlet of the vacuum scroll pump defining the inlet opening.

14 . Vacuum apparatus as claimed in claim 13 , wherein the compression ratio of the vacuum scroll pump and secondary vacuum pump operating in combination to pump the tracer gas is greater than that of the compr

Assignees

• Agilent Technologies Inc

Inventors

• Calhoun John
• Forni Ronald J
• Flynn Kevin

Classifications

• F04C23/003 Primary

  having complementary function · CPC title

• F04C25/02 Primary

  for producing high vacuum (sealing arrangements F04C27/00; silencing F04C29/06) · CPC title

• F04C18/0215

  where only one member is moving · CPC title

• F04C23/005

  of dissimilar working principle · CPC title

• F04C23/00

  Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids (F04C25/00 takes precedence) · CPC title