US3773080A

US3773080A - Air flow control valve

Info

Publication number: US3773080A
Application number: US00146576A
Authority: US
Inventors: H Raschke
Original assignee: Bullard Co
Current assignee: Bullard Co; BULLARD E CO
Priority date: 1971-05-19
Filing date: 1971-05-19
Publication date: 1973-11-20
Anticipated expiration: 1990-11-20

Abstract

A control valve assembly for regulating the flow of air to a sandblasting hood is described. The control valve assembly includes a valve housing defining an inlet and outlet passageway, and a diametrically slotted valve stem which is rotatably received within the housing, intermediate the passageways. An air bleed path in communication with the inlet and outlet passageways provides for the maintenance of a minimum flow of air through the assembly. Air flow regulation is afforded by rotation of the valve stem, 90* rotation required to open the valve from the closed position. A rotatable control knob, spring-biasedly mounted to the housing concentric to the stem, is provided which when axially displaced from the housing engages the valve stem for rotation.

Description

[ Nov. 20, 1973 24,801 1909 Great Britain..... 251/96 ABSTRACT to a sandblasting hood is described. The control valve g an inlet ally slotted in communication with the inlet and outlet passageehe ...w. m h m w w d a mm n n W 08 whm m y S u S g 0.10 .l m ,h F .mme m beh 1 m a w n m m m D Wt... 7 A odn 1 o mm m mam l n P m l 3 1 C t r 5 2 col 7 .mm 0 ti 1 6 5 a t ne m m| 1 wh w m mminoudii Primary Examiner-Arnold Rosenthal Attorney-Townsend and Townsend A control valve assembly for regulating the flow of air assembly includes a valve housing definin and outlet passageway, and a diametric valve stem which is rotatably received within the housing, intermediate the passageways. An air bleed path ways provides for the maintenance of a minimum flow of air through the assembly. Air flow regulation is afforded by rotation of the valve stem, 90 rotation required to open the valve from the closed position. A

Inventor: Herbert A. Raschke, Greenbrae,

Calif.

Assignee: E. D. Bullard Company, Sausalito,

Calif.

May 19, 1971 137/625.32, 251/96, 251/287, 251/292 Fl6k 5/02, Fl6k 5/12 251/292, 96, 287; l37/625.32, 599.1

References Cited UNITED STATES PATENTS United States Patent 1 Raschke AIR FLOW CONTROL VALVE [22] Filed:

[21] Appl. No.: 146,576

[51] Int.

[58] Field of Search....................

xuxwg 1 M Nu BU H .b Jb e e ii he mmmmumsu 8 111 t a lege an fillc 4\\ 1 .v\ k mm mm mw Mntmpcm mm B 768609 M0 333% m mmmadm m n m 96053 2 ww em my 9 4 0 3 9 7 4 wanna 1 3 2 2 3 l Patented Nov. 20, 1973 3 Sheet 1 INVENTQK HEZBEQT A. [ZASQHKE Patented Nov. 20, 1973 3,773,080

INVENTOR. HERBEET A QAGCHKE mil Patented Nov. 20, 1973 3,773,080

is Sheets-Sheet INVENTOR. HEQBEQT A. QAfDCHKE With the air flow control valves presently employed I in sandblasting operations, it is quite possible for the hood wearer to completely cut off the fiow of air to the hood either by intentionally or accidentally closing the valve. It is also likely during the course of sandblasting operations that the hood wearer will inadvertently brush against objects at the work site. If the valve is carried on the wearers belt, as is commonly the case, it too will brush against these same objects possibly to effectuate a change in the valve setting. It is an object of this invention to provide an air flow control valve which suffers none of the above-mentioned drawbacks.

Accordingly, it is one object of this invention to provide an air flow control valve assembly for regulating the flow of air to a sandblasting hood which will insure the maintaining of a minimum flow of air to the hood no matter what the setting of the valve. This object is achieved by providing in a valve assembly including a housing having axially aligned inlet and outlet passageways and a valve chamber intermediate said passageways which receives a valve stem, a channel in communication with said passageways to define an air bleed path. The air bleed path permits a limited amount of air to bypass the valve stem and thus insures the maintenance of a minimum flow of air to the hood regardless of the valve setting.

It is another object of this invention to construct an air flow control valve assembly as described above so that the selected air flow rate will not inadvertently be altered by the wearer of the sandblasting hood as he brushes against objects at the work site. This object is effectuated by providing a rotatable control knob, spring biased towards the valve housingfor regulating the valve setting. The knob, when displaced from a first, unengaged position abutting the valve housing, to a' second, engaged position, outward from the valve housing, engages the valve stem for rotation. In the unengaged position, the knob is free to rotate without effecting the valve setting.

If the knob is brushed against objects at the work site, though it may rotate, the valve setting and thus the air flow rate, will remain unaltered. Further, as the knob must be pulled outwardly from the valve housing against the force of the spring for engagement, the chance of accidental displacement to the engaged position is all but eliminated.

It is a still further object of this invention to be able to adjust the flow of air through the above-described valve assembly between a minimum and a maximum flow rate by a limited rotation of the valve stem. This object is achieved by providing a cylindrical valve stem intermediate the inlet andoutlet passageways of the valve which has an opening extending diametrically therethrough. When the opening is aligned with the inlet and outlet passageways, an air flow path is defined therebetween. Closure of the air flow path is effectuated by limited rotation of the valve stem, about rotation required for full closure.

It is a further object of this invention to provide a low-cost air flow control valve which can be fabricated from parts designed for easy casting and quick assembly.

These and other objects will become apparent after referring to the following specification and accompanying drawings, wherein:

FIG. 1 is a sectioned, perspective view of the air flow control valve assembly of this invention;

FIG. 2 is a fragmentary, sectioned top view of the inlet and outlet passageways and intermediate valve chamber, the base of the valve stem shown in section;

FIG. 3 is a sectioned detail view of the control knob assembly, the control knob shown in the disengaged position;

FIG. 4 is a view similar to FIG. 3, the control knob shown in the engaged position; and

FIGS. 5, 6 and 7 are schematic views illustrating the air flow paths through the valve assembly at different valve settings.

With reference to the drawings and particularly to FIG. 1, an air flow control valve assembly designated generally as A is illustrated comprising a valve housing B, a valve stem C, a valve housing cover D, and a valve control knob E. The flow of air through the valve assembly is determined by the relative rotative position of valve stem C within the valve housing B. Regulation of air flow rate is afforded by rotation of the valve stem C which is in turn effectuated by rotation of control knob E. Rotation of the stern, however, may only be effectuated when the control knob is in the engaged position, pulled outwardly away from the valve housing.

A first air hose (not shown) from an air purifier is secured to a hollow, cylindrical connecting means 10 which is force fitted into the exterior opening of air inlet passageway 12 in valve housing B. A second air hose (not shown) attached at its one end to a sandblasting hood is secured at its other end to neck 18 of the housing. Air entering passageway 12 can flow through the diametric opening 16 in stem C, when properly aligned, and into air outlet passageway 14 and then to the sandblasting hood.

Valve stern C is rotatably received within the valve chamber defined by cylindric wall 20. The valve stem is delimited at its central portion by cylindric wall 22 which defines a bearing surface for valve stem rotation. Extending upwardly from this central portion is shank portion 50, which is of reduced cross section. The lower portion of the stem, delimited by cylindric wall 24, extends across the inlet and outlet ports defined by

passageways

12 and 14 at their termination at wall 20. This lower portion is of a reduced cross section to define an annular air bleed path between the valve stem and wall 20 of the valve chamber. Air introduced into passageway 12 will flow around the valve stem via the air bleed path between

walls

24 and 20 and into passageway 14, regardless of the valve setting, to insure a minimum airflow.

As previously noted, diametric opening 16 provided in the lower portion of the valve stem defines an air passage between

passageways

12 and 14. This opening extends upwardly from the base of the stem to an intermediate point above the lowermost portion of the air passageway ports. The opening further defines a pair of

feet

26 and 28 at the base of the valve stem.

Feet

26 and 28 are bounded by cylindric wall 24, interior diametrically

parallel walls

30 and 31, and

semi-cylindric bottom surfaces

32 and 33.

Rotation of the valve stem is limited to 90 by the particular construction of the base of the valve stem and valve chamber as illustrated in FIGS. 1 and 2. A pie-shaped shoulder 34 having a top surface 36 and

sidewalls

37 and 38 is provided which extends upwardly from the cylindric bearing surface 40 at the base of the valve chamber to limit the rotation of the valve stem C. Bottom surface 32 of foot 26 of valve stem C rests upon surface 40 and is supported by surface 40 during rotation. Foot 28 is sufficiently foreshortened so that it can pass over surface 36 of shoulder 34 as shown in FIG. 1. From the position illustrated in FIGS. l and 2, wherein the inside wall 30 of foot 26 confronts sidewall 37 of shoulder 34, the semi-cylindric surface 33 of foot 28 lying above shoulder 34, stem C can be rotated clockwise up to 90 until wall 30 of foot 26 confronts sidewall 38 of the shoulder as indicated by the broken line in FIG. 2.

It will be apparent from FIGS. 5, 6 and 7 that the amount of air flowing through the valve is dependent upon the relative positioning of the diametric opening 16 with respect to the ports of air passageways l2 and 14. In the closed position as illustrated in FIGS. 1 and 5, wherein the diametric slot is axially perpendicular to

passageways

12 and 14, limited airflow through the valve occurs, the air passing around the stem via the annular air bleed path defined between wall 20 of the valve chamber and wall 24 of the valve stem. The air flow rate may gradually be increased by clockwise rotation of the valve stem to an intermediate flow as shown in FIG. 6. In this position, a limited amount of air passes around the valve stem as well as through the diametric opening in the stem. To achieve maximum airflow, the valve is fully rotated, 90 from the closed position to the open position illustrated in FIG. 7. In this position, diametric opening 16 is axially aligned with

passageways

12 and 14 to allow for maximum air flow between the passageways.

The valve housing cover D, seated over housing B, retains the valve stem in place. Housing cover D is secured to the housing 8 with screws (not shown) which are received within tapped

holes

62 and 44. The housing cover is formed with an opening delimited by cylindric wall 46, that registers with the opening of the valve chamber when the cover D is in place over the housing. Annular shelf 48 in housing B, concentric with shaft 20, receives an O-ring (not shown). This ()-ring serves to maintain the relative position of the stem with the valve chamber to facilitate its rotation and prevent escape of air.

Shank portion 50 of valve stem C extends through opening 60 in housing cover D and into the interior of upstanding cylindric wall 62 on cover D, this wall being concentric to opening 60.

With reference to FIGS. 3 and 4, it will be readily apparent how rotation of control knob E will effectuate rotation of the valve stem. Control knob E, which re sides within cylindric wall 62, has a base portion 6 3 which has an exterior cylindric surface sized for a run ning fit interior of the cylindric wall. Base portion 64 of the control knob is formed with a central bore at 66 to admit shank 50 therethrough. Control knob E also has an intermediate and concentric cylindric chamber 70 and a still larger concentric and cylindric cavity 72.

At the boundary between bore 66 and chamber 70 is an annular shoulder 74 that engages one end of a compression spring 76. As can be seen in FIG. 3, compression spring 76 circumscribes shank portion 50. The opposite end of spring 76 bears against a cross pin 78 which is force fitted into a suitable diametrically extending hole at the upper end of shank portion 50. The diameter of cylindric cavity 72 is larger than the length of pin 78 so that the pin and shank portion can rotate freely therein.

At the boundary between cylindrical chamber 70 and cylindric cavity 72 is an annular face 82. Extending from annular face 82 is one or more projections 84. These projections define radially extending abutments that confront pin 78 when control knob E is moved axially upward against the force of spring 76.

The rotative position of valve stem C can be conveniently adjusted by pulling control knob E outward until pin 78 engages a projection 84 as illustrated in FIG. 4. The control knob, and thus in turn the valve stem, is rotated until the desired airflow is achieved. Release of control knob E disengages spring 76, restoring the knob to the position shown in FIG. 3.

For facilitating movement of control knob E, the knob is provided with a circular flange 86 that has a roughened surface 88 located radially outward of the outward boundary of cylindric wall 62. To prevent dust and other dirt particles from interferring in the operations of the control knob, a dust cover 90 is provided which is pressure fitted in the recess 92 of flange 86.

In a preferred embodiment, the value is designed to be capable of delivering at least 15 standard cubic feet per minute of air when the valve is in the fully opened position. In the closed position, the annular bleed path permits a flow of at least 6 standard cubic feet per minute. Such minimum and maximum standard flow rates are in conformity with the standard safety regulation requirements.

The control valve assembly is usually carried by the worker over his working clothing mounted on a belt. Tap holes 94 in housing B are provided to receive attaching means for connecting the valve assembly to the belt. Carried waist high, the control valve is maintained at a comfortable position on the workers body, where it may be easily viewed and reached to effect opening or closing.

Each part of the air flow control valve of this invention is especially designed for easy casting. Virtually no finishing of the cast parts is required and thus fabrication costs are greatly reduced. The sole machining step involves the boring of a channel at the end of the valve stem for receiving the pin. To facilitate in the assembly of the valve, openings 68 are provided on wall 62 and openings 69 are provided on control knob E. When these openings are aligned, pin 78 can be easily passed therethrough and fitted into the hole provided in shank 54} to otherwise complete the valve assembly construction.

While one embodiment of the invention has been shown and described, it will be obvious that other adaptations and modifications can be made without departing from the true spirit and scope of the invention.

What is claimed is:

I. An air flow control valve comprising:

a housing having an inlet passageway and an outlet passageway;

said housing further having an internal cylindric wall that defines a cylindric valve chamber, said inlet and outlet passageways terminating in ports in said cylindric wall, said ports being at substantially the same position axially of the cylindric chamber; cylindric valve body disposed in said chamber and including means for establishing in air flow path between said inlet passage and outlet passage that affords airflow between said passages in proportion to the relative rotative position of said valve body, said valve body having an upper shank portion that extends from said housing through an opening in said housing, engaging means diametrically projecting from the shank near the end thereof;

a rotatable cylindric control knob mounted to said housing concentric with said shank, and axially displaceable from said housing, said knob having an aperture at its base through which the valve shank extends, said knob further having a first concentric cavity extending upwardly from the opening at its base and a second, larger cavity extending upwardly from said first cavity, spring means within said first concentric cavity of said knob and extending to said engaging means for biasing said knob towards said valve housing;

said knob still further including an annular shelf defined between the boundary of said first and second cavity and at least one radial projection extending from said annular shelf;

and means for axially displacing said control knob from said housing to bring the engaging means at the end of the shank into contact with said annular shelf, whereby rotation of said knob will bring said projection into confronting relationship with said engaging means, and further rotation will induce said valve body to rotate.

2. The air flow control valve of claim 1 wherein said valve body includes an intermediate cylindric portion axially remote from said ports for defining a bearing surface for rotation of said valve body in said chamber, said valve body having a lower cylindric portion opposite said ports, wherein said lower cylindric portion has a diameter less than the diameter of said chamber to define an air bleed path between said inlet and outlet passageways that is substantially constant irrespective of the rotative position of said valve body.

3. An airflow control valve assembly for regulating the flow of air to a sandblasting hood comprising:

a valve housing having an inlet passageway and an outlet passageway;

a cylindric valve stem received in a cylindric valve chamber in said housing intermediate said passageways, said valve stem defining a pair of semicylindric feet at its base, one of said feet foreshortened so as to receive projecting means therebeneath;

an opening in said valve stem defining an air flow path between said inlet and outlet passageways to afford air flow between said passages in proportion to the relative rotative position of said valve stem;

an air bleed path in communication with said inlet and outlet passageways for establishing a minimum flow of air through the valve assembly irrespective of the rotative position of said valve stem;

projecting means comprising a raised shoulder having side walls which extend upwardly from the base of the valve chamber, said rotation of the valve body within the chamber limited by said shoulder side walls through or less;

and control means comprising a cylindrical control knob concentrically mounted to the valve housing, and axially displaceable along its length to engage a projection in said valve stem, whereby when so engaged, rotation of said knob induces rotation of said valve stem.

4. An airflow control valve comprising a housing defining an inlet passage and an outlet passage, said housing further having an internal cylindric wall that defines a cylindric valve chamber having a circular base, said inlet and outlet passages terminating in ports in said cylindric wall, said ports being in substantially the same position axially as the cylindric chamber;

a valve body disposed in said chamber and having a first cylindric portion axially remote from said ports for defining a bearing surface for rotation of said valve body within said chamber, said valve body having a second cylindric portion opposite said ports, said second cylindric portion having a diameter less than the diameter of said bore to define an air bleed passage between said inlet passage and said outlet passage that is substantially constant in volume irrespective of the positioning of said valve body;

a shoulder having upstanding side walls extending from said circular base of said cylindric valve chamber, said shoulder defining a 90 segment of said base; and

a diametric slot extending from the base of said second cylindric portion across the ports of said inlet and outlet passages to establish an airflow passage between said passages, said diametric slot further defining a pair of feet of substantially semi-circular cross-section, one of said feet supported on the surface of the said circular base, the other of said feet foreshortened to receive said shoulder therebeneath whereby rotation of said valve body within said valve chamber is limited by the upstanding side walls of said shoulder.

5. The air flow control valve of claim 4 wherein said valve body has an upper shank portion which extends from said housing through an opening in said housing, engaging means provided on said shank near its end, and said means for afiording rotation of said valve body comprises a rotatable cylindric control knob mounted to said housing concentric with said valve shank, and axially displaceable from said housing, said knob having an aperture at its base through which the valve shank extends, and further having a first concentric cavity extending upwardly from the opening at its base, spring means within said first concentric cavity, said means circumscribing said shank, and extending to said engaging means, for biasing said knob toward said housing, and a second larger cavity concentric with said first cavity, the boundary between said first and second cavity defining an annular shelf, at least one radial projection extending from said shelf, and means for axially displacing said control knob from said housing to bring the engaging means proximate the end of the valve shank to bear against the annular face, whereby said projection is brought into contronting relationship with said engaging means by rotation of said knob, further rotation of said knob inducing rotation of said body.

Claims

1. An air flow control valve comprising: a housing having an inlet passageway and an outlet passageway; said housing further having an internal cylindric wall that defines a cylindric valve chamber, said inlet and outlet passageways terminating in ports in said cylindric wall, said ports being at substantially the same position axially of the cylindric chamber; a cylindric valve body disposed in said chamber and including means for establishing in air flow path between said inlet passage and outlet passage that affords airflow between said passages in proportion to the relative rotative position of said valve body, said valve body having an upper shank portion that extends from said housing through an opening in said housing, engaging means diametrically projecting from the shank near the end thereof; a rotatable cylindric control knob mounted to said housing concentric with saiD shank, and axially displaceable from said housing, said knob having an aperture at its base through which the valve shank extends, said knob further having a first concentric cavity extending upwardly from the opening at its base and a second, larger cavity extending upwardly from said first cavity, spring means within said first concentric cavity of said knob and extending to said engaging means for biasing said knob towards said valve housing; said knob still further including an annular shelf defined between the boundary of said first and second cavity and at least one radial projection extending from said annular shelf; and means for axially displacing said control knob from said housing to bring the engaging means at the end of the shank into contact with said annular shelf, whereby rotation of said knob will bring said projection into confronting relationship with said engaging means, and further rotation will induce said valve body to rotate.

3. An airflow control valve assembly for regulating the flow of air to a sandblasting hood comprising: a valve housing having an inlet passageway and an outlet passageway; a cylindric valve stem received in a cylindric valve chamber in said housing intermediate said passageways, said valve stem defining a pair of semi-cylindric feet at its base, one of said feet foreshortened so as to receive projecting means there-beneath; an opening in said valve stem defining an air flow path between said inlet and outlet passageways to afford air flow between said passages in proportion to the relative rotative position of said valve stem; an air bleed path in communication with said inlet and outlet passageways for establishing a minimum flow of air through the valve assembly irrespective of the rotative position of said valve stem; projecting means comprising a raised shoulder having side walls which extend upwardly from the base of the valve chamber, said rotation of the valve body within the chamber limited by said shoulder side walls through 90* or less; and control means comprising a cylindrical control knob concentrically mounted to the valve housing, and axially displaceable along its length to engage a projection in said valve stem, whereby when so engaged, rotation of said knob induces rotation of said valve stem.

4. An airflow control valve comprising a housing defining an inlet passage and an outlet passage, said housing further having an internal cylindric wall that defines a cylindric valve chamber having a circular base, said inlet and outlet passages terminating in ports in said cylindric wall, said ports being in substantially the same position axially as the cylindric chamber; a valve body disposed in said chamber and having a first cylindric portion axially remote from said ports for defining a bearing surface for rotation of said valve body within said chamber, said valve body having a second cylindric portion opposite said ports, said second cylindric portion having a diameter less than the diameter of said bore to define an air bleed passage between said inlet passage and said outlet passage that is substantially constant in volume irrespective of the positioning of said valve body; a shoulder having upstanding side walls extending from said circular base of said cylindric valve chamber, said shoulder defining a 90* segment of said base; and a diametric slot extending from the base of said second cylindric portion acrosS the ports of said inlet and outlet passages to establish an airflow passage between said passages, said diametric slot further defining a pair of feet of substantially semi-circular cross-section, one of said feet supported on the surface of the said circular base, the other of said feet foreshortened to receive said shoulder therebeneath whereby rotation of said valve body within said valve chamber is limited by the upstanding side walls of said shoulder.

5. The air flow control valve of claim 4 wherein said valve body has an upper shank portion which extends from said housing through an opening in said housing, engaging means provided on said shank near its end, and said means for affording rotation of said valve body comprises a rotatable cylindric control knob mounted to said housing concentric with said valve shank, and axially displaceable from said housing, said knob having an aperture at its base through which the valve shank extends, and further having a first concentric cavity extending upwardly from the opening at its base, spring means within said first concentric cavity, said means circumscribing said shank, and extending to said engaging means, for biasing said knob toward said housing, and a second larger cavity concentric with said first cavity, the boundary between said first and second cavity defining an annular shelf, at least one radial projection extending from said shelf, and means for axially displacing said control knob from said housing to bring the engaging means proximate the end of the valve shank to bear against the annular face, whereby said projection is brought into contronting relationship with said engaging means by rotation of said knob, further rotation of said knob inducing rotation of said body.