GB2025582A - Ejector valve assemblies - Google Patents

Ejector valve assemblies Download PDF

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Publication number
GB2025582A
GB2025582A GB7924473A GB7924473A GB2025582A GB 2025582 A GB2025582 A GB 2025582A GB 7924473 A GB7924473 A GB 7924473A GB 7924473 A GB7924473 A GB 7924473A GB 2025582 A GB2025582 A GB 2025582A
Authority
GB
United Kingdom
Prior art keywords
valve
air
chest
piston
space
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB7924473A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
De Beers Industrial Diamond Division Pty Ltd
Original Assignee
De Beers Industrial Diamond Division Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by De Beers Industrial Diamond Division Pty Ltd filed Critical De Beers Industrial Diamond Division Pty Ltd
Publication of GB2025582A publication Critical patent/GB2025582A/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K31/00—Actuating devices; Operating means; Releasing devices
    • F16K31/12—Actuating devices; Operating means; Releasing devices actuated by fluid
    • F16K31/36—Actuating devices; Operating means; Releasing devices actuated by fluid in which fluid from the circuit is constantly supplied to the fluid motor
    • F16K31/38—Actuating devices; Operating means; Releasing devices actuated by fluid in which fluid from the circuit is constantly supplied to the fluid motor in which the fluid works directly on both sides of the fluid motor, one side being connected by means of a restricted passage and the motor being actuated by operating a discharge from that side
    • F16K31/383—Actuating devices; Operating means; Releasing devices actuated by fluid in which fluid from the circuit is constantly supplied to the fluid motor in which the fluid works directly on both sides of the fluid motor, one side being connected by means of a restricted passage and the motor being actuated by operating a discharge from that side the fluid acting on a piston

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Jet Pumps And Other Pumps (AREA)

Abstract

An ejector valve assembly has a valve chest 11 connected to a source of compressed air. A mushroom valve 18 controls flow between the chest 11 and a nozzle 17. The valve 18 is actuated by a piston 21 which is acted on by air from the chest 11 through a pilot valve 24. <IMAGE>

Description

SPECIFICATION Ejector valve assemblies This invention relates to ejector valve assemblies of the kind which blow a jet of air on to an object to be ejected from a path which it is following or a position which it is occupying.
A valve assembly of the kind in question is known and comprises a spool valve actuated by a pilot valve for controlling the flow of air from a source to the nozzle forming the jet. The spool valve is biased to its position of closure by means of air pressure at one end of it. The pilot valve controls the admission of air at a higher pressure to the other end of the spool valve. Thus the air at the first end acts as a pneumatic spring. In practice air at three different pressures are required. In addition due to the pneumatic spring there is bounce in the action of the spool so that often instead of one jet blast two closely successive blasts occur.
It is an object of the invention to provide an assembly which produces a single blast of a shorter predetermined duration than that currently achieved.
Summary of the Invention According to the invention an ejector valve assembly comprises a valve chest adapted to be connected to a source of gas under pressure; an ejector nozzle; a valve opening connecting the chest to the nozzle; a poppet valve having a head and a stem with the head arranged to close the valve opening and biased to closure by gas in the chest; a piston on the stem and having a working face opposed to the head; and a pilot valve for admitting compressed gas to the working face of the piston, the area of the piston being so chosen that when gas is admitted to the working face of the piston the poppet valve is lifted off the opening.
Description of the Drawing Shows a section through a valve assembly according to the invention.
Description of a Preferred Embodiment The illustrated embodiment has a base 10 in which is formed a valve chest 11. Compressed air is fed to the valve chest 11 through an inlet 12.
Mounted to the base 10 is a valve body 13 which provides an annular valve seat 14, a flow space 15 and houses a bush 16. The flow space 15 communicates with a narrow and transversely widened ejector nozzle 17.
A poppet valve member 18 co-operates with the valve seat 14. The valve member 18 has a stem 19 guided by the bush 16. The stem 19 terminates in a flange 20. As shown the stem 19 and the flange 20 are hollowed out to reduce weight. A closure plate 21 provides the flange 20 with a complete piston surface. The space behind the flange 20 is vented to atmosphere through a vent 22.
A pilot valve housing 23 is mounted on the body 13. It contains a pilot valve 24 of known construction.
The space 25 around the pilot valve 24 communicates with the valve chest 11 through a bore 26 so that the pressure in the chest 11 is the same as in the space 25. The pilot valve operates to admit air to a piston space 27 above the flange 20. The space 27 is constantly vented to atmosphere through a narrow vent 30 acting as a restrictive orifice.
The size of the poppet member 18 and the area of the flange 20 are so chosen that with equal air pressures acting on them, the poppet member 18 is pushed off its seat 14.
In use the assembly is mounted with the nozzle 17 directed at a zone which has to be swept by a jet of air when an electrical signal is fed to the pilot valve 24. An air supply at a suitable pressure is connected to the inlet 12. In the absence of a signal the parts assume the position as illustrated. When a signal arrives, air is admitted to the space 27 and the poppet member 18 is pushed off its seat to allow air from the valve chest 11 to flow through the nozzle 17. When the signal ceases the space 27 is immediately vented to atmosphere. As a result of the pressure in the chest 11 and the pressure differential across the poppet member 18 caused by the flow of air, the poppet member 18 closes on its seat 14 immediately. There is no bounce.
In addition, the speed of opening and closing is extremely fast, being approximately three times faster for the same air flow than the prior art spool valve.
1. An ejector valve assembly comprising a valve chest adapted to be connected to a source of gas under pressure; an ejector nozzle; a valve opening connecting the chest to the nozzle; a poppet valve having a head and a stem with the head arranged to close the valve opening and biased to closure by gas in the chest; a piston on the stem and having a working face opposed to the head; and a pilot valve for admitting compressed gas to the working face of the piston, the area of the piston being so chosen that when gas is admitted to the working face of the piston the poppet valve is lifted off the opening.
2. The valve assembly claimed in claim 1 in which the pilot valve is connected to the valve chest to admit gas from the valve chest to the working area of the piston.
3. The valve assembly claimed in either of the above claims in which the working face of the piston is vented to atmosphere through a restrictive orifice.
4. The valve assembly claimed in any one of the above claims in which the face of the piston opposed to the working face is vented to atmosphere.
5. An ejector valve assembly substantially as herein described and illustrated in the accompanying drawing.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Ejector valve assemblies This invention relates to ejector valve assemblies of the kind which blow a jet of air on to an object to be ejected from a path which it is following or a position which it is occupying. A valve assembly of the kind in question is known and comprises a spool valve actuated by a pilot valve for controlling the flow of air from a source to the nozzle forming the jet. The spool valve is biased to its position of closure by means of air pressure at one end of it. The pilot valve controls the admission of air at a higher pressure to the other end of the spool valve. Thus the air at the first end acts as a pneumatic spring. In practice air at three different pressures are required. In addition due to the pneumatic spring there is bounce in the action of the spool so that often instead of one jet blast two closely successive blasts occur. It is an object of the invention to provide an assembly which produces a single blast of a shorter predetermined duration than that currently achieved. Summary of the Invention According to the invention an ejector valve assembly comprises a valve chest adapted to be connected to a source of gas under pressure; an ejector nozzle; a valve opening connecting the chest to the nozzle; a poppet valve having a head and a stem with the head arranged to close the valve opening and biased to closure by gas in the chest; a piston on the stem and having a working face opposed to the head; and a pilot valve for admitting compressed gas to the working face of the piston, the area of the piston being so chosen that when gas is admitted to the working face of the piston the poppet valve is lifted off the opening. Description of the Drawing Shows a section through a valve assembly according to the invention. Description of a Preferred Embodiment The illustrated embodiment has a base 10 in which is formed a valve chest 11. Compressed air is fed to the valve chest 11 through an inlet 12. Mounted to the base 10 is a valve body 13 which provides an annular valve seat 14, a flow space 15 and houses a bush 16. The flow space 15 communicates with a narrow and transversely widened ejector nozzle 17. A poppet valve member 18 co-operates with the valve seat 14. The valve member 18 has a stem 19 guided by the bush 16. The stem 19 terminates in a flange 20. As shown the stem 19 and the flange 20 are hollowed out to reduce weight. A closure plate 21 provides the flange 20 with a complete piston surface. The space behind the flange 20 is vented to atmosphere through a vent 22. A pilot valve housing 23 is mounted on the body 13. It contains a pilot valve 24 of known construction. The space 25 around the pilot valve 24 communicates with the valve chest 11 through a bore 26 so that the pressure in the chest 11 is the same as in the space 25. The pilot valve operates to admit air to a piston space 27 above the flange 20. The space 27 is constantly vented to atmosphere through a narrow vent 30 acting as a restrictive orifice. The size of the poppet member 18 and the area of the flange 20 are so chosen that with equal air pressures acting on them, the poppet member 18 is pushed off its seat 14. In use the assembly is mounted with the nozzle 17 directed at a zone which has to be swept by a jet of air when an electrical signal is fed to the pilot valve 24. An air supply at a suitable pressure is connected to the inlet 12. In the absence of a signal the parts assume the position as illustrated. When a signal arrives, air is admitted to the space 27 and the poppet member 18 is pushed off its seat to allow air from the valve chest 11 to flow through the nozzle 17. When the signal ceases the space 27 is immediately vented to atmosphere. As a result of the pressure in the chest 11 and the pressure differential across the poppet member 18 caused by the flow of air, the poppet member 18 closes on its seat 14 immediately. There is no bounce. In addition, the speed of opening and closing is extremely fast, being approximately three times faster for the same air flow than the prior art spool valve. CLAIMS
1. An ejector valve assembly comprising a valve chest adapted to be connected to a source of gas under pressure; an ejector nozzle; a valve opening connecting the chest to the nozzle; a poppet valve having a head and a stem with the head arranged to close the valve opening and biased to closure by gas in the chest; a piston on the stem and having a working face opposed to the head; and a pilot valve for admitting compressed gas to the working face of the piston, the area of the piston being so chosen that when gas is admitted to the working face of the piston the poppet valve is lifted off the opening.
2. The valve assembly claimed in claim 1 in which the pilot valve is connected to the valve chest to admit gas from the valve chest to the working area of the piston.
3. The valve assembly claimed in either of the above claims in which the working face of the piston is vented to atmosphere through a restrictive orifice.
4. The valve assembly claimed in any one of the above claims in which the face of the piston opposed to the working face is vented to atmosphere.
5. An ejector valve assembly substantially as herein described and illustrated in the accompanying drawing.
GB7924473A 1978-07-14 1979-07-13 Ejector valve assemblies Withdrawn GB2025582A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ZA784019A ZA784019B (en) 1978-07-14 1978-07-14 Ejector valve assemblies

Publications (1)

Publication Number Publication Date
GB2025582A true GB2025582A (en) 1980-01-23

Family

ID=25573153

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7924473A Withdrawn GB2025582A (en) 1978-07-14 1979-07-13 Ejector valve assemblies

Country Status (3)

Country Link
AU (1) AU4882279A (en)
GB (1) GB2025582A (en)
ZA (1) ZA784019B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2140973A (en) * 1983-05-20 1984-12-05 Ako Werke Gmbh & Co A device for the control of an electric fence
GB2156290A (en) * 1984-03-27 1985-10-09 Everaids Limited Rockets and rocket motors

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2140973A (en) * 1983-05-20 1984-12-05 Ako Werke Gmbh & Co A device for the control of an electric fence
GB2156290A (en) * 1984-03-27 1985-10-09 Everaids Limited Rockets and rocket motors

Also Published As

Publication number Publication date
ZA784019B (en) 1980-01-30
AU4882279A (en) 1980-01-17

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Legal Events

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)