VALVE SEALS
United States Patent 3799187
Rolling and sliding gate-type valves for controlling the flow of dry particulate material are provided with improved blade seals to handle finer materials over increased pressure differentials. Improved blade side and end sealing arrangements for adjusting the position of a curved blade on its blade-supporting arm permits the blade to be accurately adjusted in relation to the seals.
US Patent References:
Gate valve
Wey - April 1958 - 2829862
Knife gate valve
Clandinin - October 1964 - 3154287
/3587623.html
Wilson - June 1971 - 3587623
Gate valve
Armstrong - April 1968 - 3380475
GATE VALVE HAVING RELATIVELY MOVABLE SEAT MEMBERS
Hastings - April 1972 - 3658084
Gate valve
Wey - April 1958 - 2829862
Knife gate valve
Clandinin - October 1964 - 3154287
/3587623.html
Wilson - June 1971 - 3587623
Gate valve
Armstrong - April 1968 - 3380475
GATE VALVE HAVING RELATIVELY MOVABLE SEAT MEMBERS
Hastings - April 1972 - 3658084
Application Number:
05/294454
Publication Date:
03/26/1974
Filing Date:
10/02/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
222/345, 251/328, 251/84
International Classes:
F16K3/02; F16K3/04; F16K13/02; F16K13/00; F16K3/20
Field of Search:
137/246.22 251/84,328 222/345
Primary Examiner:
Weakley, Harold W.
Attorney, Agent or Firm:
Biebel, French & Bugg
Claims:
What is claimed is
1. In a gate type valve in which a curved blade is supported on arm means for arcuate movement into flow blocking and flow permitting relations to a valve housing, and in which side wall and end wall seals engage the blade for sealing the same with respect to the housing walls, the improvement in blade mounting comprising a plurality of adjusting screws between said blade and said arm means and movable to vary the position of said blade with respect to said arm means and to said seals, and means for securing said blade on said arm means in an adjusted position.
2. The improvement of claim 1 in which said screws are threadedly received in said arm means and bear against said blade, said screws being further arranged in pairs set at an obligue angle to the direction of blade movement.
3. In a valve adapted to control the flow of dry particulate material having a generally rectangular valve housing and a curved flow control valve blade mounted on arms for movement substantially about its center of curvature through a blade slot in the back wall of said housing between flow permitting and flow blocking positions, the improvement in elastomeric seals for sealing the blade at said slot and at the side walls of the housing in its closed position, comprising a pair of curved elastomeric side seals mounted on inside side walls of the valve housing extending substantially from the front wall of the housing to the back wall of the housing and having lower edges which are engageable with the upper surface of the blade in the closed position of the blade, blade-slot seals including an upper elastomeric seal and a lower elastomeric seal each mounted on the outside surface of said end wall adjacent said slot respectively on opposite sides of said blade and being formed with ends which are in overlying engagement with the respective top and bottom surfaces of said blade and which extend inwardly into said slot, and a pair of side plugs which are formed separately from said side and end seals positioned at the opposite sides of said blade in said slot in the corner space between the adjacent end and side seals in running engagement with the side edges of said blade and closing the corner gap which would otherwise be formed between the side and end seals.
4. The sealing arrangement of claim 3 in which said side seals further comprise a vertical body portion which resiliently engages the sides of the blade in its said closed position and an integral depending lip extending inwardly from said side portion in overlying relation to the adjacent upper edge of the blade and engaging the top surface of the blade so that deflection of said side portion and material in said valve on said blade causes said lip to bear down on said blade top surfaces.
5. The seal arrangement of claim 3 further comprising a second set of elastomeric blade slot seals mounted on said back wall in spaced relation to said blade slot seals, said second set of seals having blade-engaging curved ends in over-lying relation to the respective top and bottom surfaces of said blade and defining air gaps between the upper and lower pairs of blade slot seals, said plugs being proportioned to close the spaces at the blade edges between the upper and lower pairs of said end seals, and means for applying air under pressure into said spaces.
6. In a valve adapted to control the flow of dry particulate material having a generally rectangular valve housing and a curved flow control valve blade mounted on arms for movement substantially about its center of curvature through a blade slot in the back wall of said housing between flow permitting and flow blocking positions, the improvement in elastomeric seals for sealing the blade at the side walls of the housing in its closed position, comprising a pair of curved elastomeric side seals mounted on inside side walls of the valve housing extending substantially from the front wall of the housing to the back wall of the housing and having lower edges which are engageable with the upper surface of the blade in the closed position of the blade, side seals having a body portion which resiliently engages the sides of the blade and an integral depending lip extending inwardly from said side portion in overlying relation to the upper edge of the blade and engaging the top surface thereof so that deflection of said side portions by said blade causes said lips to bear down on said blade top surfaces.
7. In a valve adapted to control the flow of dry particulate material having a generally rectangular valve housing and a flow control valve blade mounted for movement through a blade slot in the back wall of said housing between flow permitting and flow blocking positions, the improvement in elastomeric seals for sealing the blade at the walls of the housing in its closed position, comprising a pair of elastomeric side seals mounted on inside side walls of the valve housing extending substantially from the front wall of the housing to the back wall of the housing and having lower edges which are engageable with the upper surface of the blade in the closed position of the blade, said side seals further having vertical body portions which resiliently engage the sides of the blade and integral depending lips extending inwardly from said side portions in overlying relation to the upper edges of the blade and engaging the top surfaces of the blade so that deflection of said side by said blade portions and the weight of material on said blade cause said lips to bear down on said blade top surface, and means on said back wall sealing said blade at said blade slot.
1. In a gate type valve in which a curved blade is supported on arm means for arcuate movement into flow blocking and flow permitting relations to a valve housing, and in which side wall and end wall seals engage the blade for sealing the same with respect to the housing walls, the improvement in blade mounting comprising a plurality of adjusting screws between said blade and said arm means and movable to vary the position of said blade with respect to said arm means and to said seals, and means for securing said blade on said arm means in an adjusted position.
2. The improvement of claim 1 in which said screws are threadedly received in said arm means and bear against said blade, said screws being further arranged in pairs set at an obligue angle to the direction of blade movement.
3. In a valve adapted to control the flow of dry particulate material having a generally rectangular valve housing and a curved flow control valve blade mounted on arms for movement substantially about its center of curvature through a blade slot in the back wall of said housing between flow permitting and flow blocking positions, the improvement in elastomeric seals for sealing the blade at said slot and at the side walls of the housing in its closed position, comprising a pair of curved elastomeric side seals mounted on inside side walls of the valve housing extending substantially from the front wall of the housing to the back wall of the housing and having lower edges which are engageable with the upper surface of the blade in the closed position of the blade, blade-slot seals including an upper elastomeric seal and a lower elastomeric seal each mounted on the outside surface of said end wall adjacent said slot respectively on opposite sides of said blade and being formed with ends which are in overlying engagement with the respective top and bottom surfaces of said blade and which extend inwardly into said slot, and a pair of side plugs which are formed separately from said side and end seals positioned at the opposite sides of said blade in said slot in the corner space between the adjacent end and side seals in running engagement with the side edges of said blade and closing the corner gap which would otherwise be formed between the side and end seals.
4. The sealing arrangement of claim 3 in which said side seals further comprise a vertical body portion which resiliently engages the sides of the blade in its said closed position and an integral depending lip extending inwardly from said side portion in overlying relation to the adjacent upper edge of the blade and engaging the top surface of the blade so that deflection of said side portion and material in said valve on said blade causes said lip to bear down on said blade top surfaces.
5. The seal arrangement of claim 3 further comprising a second set of elastomeric blade slot seals mounted on said back wall in spaced relation to said blade slot seals, said second set of seals having blade-engaging curved ends in over-lying relation to the respective top and bottom surfaces of said blade and defining air gaps between the upper and lower pairs of blade slot seals, said plugs being proportioned to close the spaces at the blade edges between the upper and lower pairs of said end seals, and means for applying air under pressure into said spaces.
6. In a valve adapted to control the flow of dry particulate material having a generally rectangular valve housing and a curved flow control valve blade mounted on arms for movement substantially about its center of curvature through a blade slot in the back wall of said housing between flow permitting and flow blocking positions, the improvement in elastomeric seals for sealing the blade at the side walls of the housing in its closed position, comprising a pair of curved elastomeric side seals mounted on inside side walls of the valve housing extending substantially from the front wall of the housing to the back wall of the housing and having lower edges which are engageable with the upper surface of the blade in the closed position of the blade, side seals having a body portion which resiliently engages the sides of the blade and an integral depending lip extending inwardly from said side portion in overlying relation to the upper edge of the blade and engaging the top surface thereof so that deflection of said side portions by said blade causes said lips to bear down on said blade top surfaces.
7. In a valve adapted to control the flow of dry particulate material having a generally rectangular valve housing and a flow control valve blade mounted for movement through a blade slot in the back wall of said housing between flow permitting and flow blocking positions, the improvement in elastomeric seals for sealing the blade at the walls of the housing in its closed position, comprising a pair of elastomeric side seals mounted on inside side walls of the valve housing extending substantially from the front wall of the housing to the back wall of the housing and having lower edges which are engageable with the upper surface of the blade in the closed position of the blade, said side seals further having vertical body portions which resiliently engage the sides of the blade and integral depending lips extending inwardly from said side portions in overlying relation to the upper edges of the blade and engaging the top surfaces of the blade so that deflection of said side by said blade portions and the weight of material on said blade cause said lips to bear down on said blade top surface, and means on said back wall sealing said blade at said blade slot.
Description:
BACKGROUND OF THE INVENTION
The sealing requirement for gate-type valves which handle dry particulate material has become more severe in recent years due to the desire to use such valves for the handling of very fine matter, such as flay ash or the like, or materials which having a high percentage of dust in them, together with the requirement that the valves be effective to control the flow over relatively higher pressure differentials.
My prior U.S. Pat., Nos. 3,380,475 issued April 30, 1968, and 3,556,358 issued Jan. 19, 1971, show forms of sealing arrangements which have proved to be effective and which have been successfully employed for their intended use, in rolling blade or gate-type valves. However, the demand for handling even finer material over greater pressure differentials has provided a need for still better seals.
SUMMARY OF THE INVENTION
The present invention relates to valve seals adapted for gate-type or slide-type valves, and particularly adapted for the gate-type valves as shown in my prior U.S. Pat. Nos. 3,380,475, 3,556,358 and 3,589,670. An improved sealing arrangement includes improved side seals which engage both the top and the sides of the blade simultaneously. In addition, improved end seals are disclosed and in one embodiment a dual end seal is disclosed which defines therebetween a chamber within which low-pressure air or gas may be admitted for providing a still more effective seal between the blade and the end wall of the valve. Also, specially designed end plugs are disclosed which are inserted at the intersection of the side and end seals and are effective to close the corner gaps which would otherwise be formed between these seals and form a complete seal with the blade.
A further feature of the present invention resides in an arrangement for aligning or adjusting the position of the blade of the valve on the blade-supporting arms so that the blade runs true to the valve body, the blade slot and to the seals.
It is accordingly an important object of this invention to provide improved side and end seal arrangements for moving blade-type valves for controlling the flow of dry particulate matter.
Another important object of the invention is the provision of seals which are particularly adapted for use with rolling blade type valves of the types shown in my U.S. Pat. Nos. 3,380,475 and 3,556,358, although the particular seal arrangement disclosed herein may be used with flat slide - type gate valves.
A further object of the invention is the provision of a sealing plug to fill the gap at the blade edge between a side seal and a pair of end seals.
A still further object is the provision of an improved double end seal defining a closed air gap which may be pressurized by air from a suitable source.
Another object of the invention is the provision of blade adjusting means by which the position of the blade on the arm may be accurately determined in relation to the side and end seals.
These and other objects and advantages of the present invention will be apparent from the following description, the accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a double or lock-gate valve incorporating the sealing arrangement of my invention;
FIG. 2 is a fragmentary enlarged vertical section through the valve of FIG. 1 showing the improved end and side seals;
FIG. 3 is a further enlarged fragmentary vertical section through one side wall of the valve showing the improved side seals, taken generally along the lines 3--3 of FIG. 2;
FIG. 4 is a fragmentary section showing the relation of the end and side seals, with the side plug seal inserted, looking generally along the line 4--4 of FIG. 2;
FIG. 5 is an elevation view showing also the relation of the end and side seals and showing the side plug seal in exploded relation;
FIG. 6 is an enlarged exploded view showing the relation of the side seal, the end seal, and the side seal plug;
FIG. 7 is a view similar to FIG. 8 but looking at the same parts from a different angle;
FIG. 8 is an enlarged vertical section through the end wall of the valve showing the relation of the side and end seals;
FIG. 9 is a modification of an end seal showing a double end seal arrangement;
FIG. 10 is a perspective view of a modified side seal plug used with the embodiment of FIG. 9;
FIG. 10A shows another form of the side seal;
FIG. 11 is a section taken generally along the line 11--11 of FIG. 9;
FIG. 12 is a fragmentary vertical section showing the side seal as applied to a flat slide type of valve;
FIG. 13 is a fragmentary perspective showing an improved arrangement for mounting a curved blade on the blade support arm;
FIG. 14 is a fragmentary view of the blade and the supporting arm; and
FIG. 15 is an enlarged section through the blade adjusting mechanism taken along the line 15--15 of FIG. 14.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIGS. 1-3, a rotary double-bladed air lock valve which is particularly adapted to make beneficial use of the improved seals of this invention is illustrated generally at 20. The valve 20 includes a valve housing 22 and a pair of arcuate blades 23 and 24 mounted on suitable supporting arms in accordance with the teachings of my U.S. Pat. No. 3,556,358. The valve body 22 is generally rectangular in cross section and may be considered as having a pair of spaced side walls 25, a rear end wall 26 through which the blades 23 and 24 move, and a front end wall 27 (FIG. 2). As fully disclosed in my U.S. Pat. No. '358, the end wall 26 is slotted at transverse regions adjacent the upper and lower ends of the body 22 through which the blades 24 and 23 respectively move within the housing 22 on support arms 28 and 29.
The improved elastomeric top side seals are illustrated generally at 30 in FIGS. 2 and 3 and extend arcuately between the front wall 27 and the back wall 26 of the valve body 22, and include vertical inwardly offset side portions 32 which engage the sides of the respective blades. A depending elastic lip or finger portion 33 is somewhat thinner and more flexible than the side portion 32 and extends downwardly and inwardly from a region adjacent the top of the side portion 32 and engages the top of the respective blade at a region which is inwardly offset from the blade edge. A similar side seal 30a is used for the bottom blade and is of the same cross-sectional configuration as the seal 30. The seals 30 and 30a may be cast or extruded and then curved to the desired blade curvature, or may be cast so as to conform to the curvature of the blade.
Curved seal retainer plates 35 (top) and 35a (bottom) are supported on the side walls by bolts 36 and retain an upper flat portions 38 of the seals 30 and 30a against the respective side walls. The lower end of each seal 30 and 30a is provided with an inwardly extending portion 32' to define a clearance space 40 between the side wall and the portion 32. The vertical portion 32 deflects somewhat with blade movement thereby bringing the finger portion 33 downwardly and into sealing engagement with the upper surface of the blade 23 or 24. In addition, the weight of the material on the blade also engages the finger portion 33 and causes it to deflect or bear against the upper surface of the blade thereby forming an effective seal between the sides of the blade and the side walls of the housing 22. With this arrangement, the blade is sealed along its edge as well as its top surface.
The construction of the end wall seal is illustrated with respect to the upper blade 24, it being understood that an identical seal arrangement is employed with respect to the lower blade 23. Referring to FIGS. 2 and 8, it will be seen that the end wall 26 is inclined to the valve body and is formed with a blade slot 43 through which the blade 24 moves substantially at right angles to the inclined end wall. A pair of essentially identical elastomeric end seals 44 extend from positions on either side of the blade outside of the wall 26 with inwardly turned blade-engaging ends 45 received within the slot 43 and respectively in overlying and underlying relation to the blade. The ends 45 are proportioned to extend a short distance inside the housing 22. The seal retainer plates 46 are held by bolts 47 and are thus external accessible for ease of removal and replacement of the seals.
The end seals 44 extend the full width of the end walls 42 and are cut out or notched as shown at 48 in FIG. 6 to receive the adjacent ends of the side seals 30. The depth of the cut-outs 48 corresponds approximately to the extent to which the seals 44 extend into the interior of the valve housing.
The arrangement of the pairs of end seals 44 with the inwardly turned ends 45 (FIG. 8) extending over the blade 24 and the side seals 30 inevitably results in the formation of a clearance gap at the region of the blade as it passes through the slot 43. For this purpose, an elastomeric end seal plug 50 is employed shown in FIGS. 5-7. The plug 50 is formed with a tapered transversely thin body portion 52 and a transversely thinner locating foot 53. The locating foot 53 is formed with tapered sides 54 adapted to be received within the clearance space 40 defined by the side seal 30, as shown in FIG. 7. The tapered body portion 52 is proportioned to form a close running fit with the side edge of the blade 23 or 24. The portion 52 is formed with upper and lower curved sides 55 which are adapted to be received against the adjacent curved surfaces of the end seals 44, at the curve regions 45 thereof. When inserted, the foot 53 snaps in position inwardly of the cut-out portions 48 and is self-holding by the end seals 44 in this position.
A pair of the end seal plugs 50 are employed for each blade at the opposite sides of each blade. The body portions 52 extend in direction of blade movement between the end seals and side seals for sealing the corner gaps which would otherwise be formed between the side and end seals.
The seals 30, 44 and 50 should be resistant to wear and abrasion and resistant to heat if present and yet should be sufficiently flexible to conform to and bear against the surface of the blade being sealed. Plain and food grade urethane, filled urethanes, silicones and glass or nickel-filled polytetrafluoroethylenes are examples of suitable sealing materials. Flexible metal wipers may be also used for the end seals 44.
A modification of an end wall seal arrangement and modified side seal plug is illustrated in FIGS. 9-11, in which spacers 60 are used to support a pair of secondary blade seals 62 and 63. The seals 62 and 63 are constructed similarly to the seals 44. The spacers 60 set the secondary seals 62 and 63 outwardly of the primary end seals 44 and define therebetween transverse open spaces 65 at locations above and below the blade 24.
A modified end seal plug 70 (FIG. 10) or 70a (FIG. 10A) which has a body portion 72 with outer curved surfaces 73 conforming to the back surfaces of the outer set of seals 62 and 63. The plug 70 has an arrow-shaped portion 74 adapted to be received just inwardly of the inwardly turned ends 75 of the seals 62 and 63. The portions 72 and 74 of the plug 70 are of the same thickness, and when inserted in position as shown in FIG. 9, it is self-holding by reason of engagement of the portion 74 with the seals 62 and 63. The plug 70A may be used in lieu of the plug 70 and has a foot 76 received in the seal recess 40 as in the case of the plug 50, and forms a seal with the side edges of both sets of end seals.
Means for pressurizing the spaces 65 includes a pair of inlets 77 formed through the seals 62 and 63 and leading into the spaces 65, as shown in FIG. 11. Preferably, air under relatively low pressure, but in excess of that in the body itself, may be applied to the inlets 77 to pressurize the spaces 65. This pressure resists any tendency for material under pressure to leak by the primary seals 44 and into the space 65.
The spacers 60 and seal 62 and 63 may be made in one piece, if desired. Preferably, the seals 62 are made of material somewhat softer than that of the seals 44. The retainer plates 46 and the bolts 47' are employed to retain the seal assembly of FIG. 9 against the adjacent end wall in the manner described in connection with the single seal arrangement of FIG. 8.
The improved seals of this invention are not limited in use to valves having curved blades, although they are particularly adapted for use with such valves. They may thus be used with advantage in valves having flat blades commonly known as a flat slide-type valve, an example being illustrated in FIG. 12. In FIG. 12, the side wall 25' of a slide-type valve is illustrated as supporting the side seal 30 in engagement with the flat slide blade 24'. The blade 24' is supported for movement conventionally on side wall-supported rollers 80, one such roller being illustrated in FIG. 12. The improved end seals of FIGS. 8 or 9 may also be used to seal the blade 24' of a slide-type valve.
In order to achieve an effective seal between the surfaces of the blade 24 and the side and end seals, it is important that the blade track accurately along its path of movement and that it be properly positioned against the side seals in its closed position. The traverse and positioning of the blade is even more critical with the use of high durometer abrasion resistant seal materials. Therefore, the invention includes means for adjusting the relative angular position of the blades with respect to the supporting arms.
As shown in FIG. 13, a blade 24 is supported on generally U-shaped arms 28 and is secured thereto by bolts 82. Adjusting means includes two pairs of set screws 86 which extend from a position beneath the arms 28 through tapped openings in the arms into engagement with the adjacent lower surface of the blade 24 at an oblique angle of approximately 45° to blade movement. The set screws 86 bear against the blade lower surface and may be adjusted to vary the tilt and arc of the blade with respect to the arms 28. The blade 24 may then be secured in the adjusted position by tightening the bolts 82 to bring the blade 24 firmly against the set screws 86. In this manner, slight irregularities in the manufacture of the blades, supporting arms, or the pivot points for these arms and slight irregularities in the curvature of the blade itself may be compensated for to assure a proper fit of the blade with both the side seals and the end seals.
While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention.
The sealing requirement for gate-type valves which handle dry particulate material has become more severe in recent years due to the desire to use such valves for the handling of very fine matter, such as flay ash or the like, or materials which having a high percentage of dust in them, together with the requirement that the valves be effective to control the flow over relatively higher pressure differentials.
My prior U.S. Pat., Nos. 3,380,475 issued April 30, 1968, and 3,556,358 issued Jan. 19, 1971, show forms of sealing arrangements which have proved to be effective and which have been successfully employed for their intended use, in rolling blade or gate-type valves. However, the demand for handling even finer material over greater pressure differentials has provided a need for still better seals.
SUMMARY OF THE INVENTION
The present invention relates to valve seals adapted for gate-type or slide-type valves, and particularly adapted for the gate-type valves as shown in my prior U.S. Pat. Nos. 3,380,475, 3,556,358 and 3,589,670. An improved sealing arrangement includes improved side seals which engage both the top and the sides of the blade simultaneously. In addition, improved end seals are disclosed and in one embodiment a dual end seal is disclosed which defines therebetween a chamber within which low-pressure air or gas may be admitted for providing a still more effective seal between the blade and the end wall of the valve. Also, specially designed end plugs are disclosed which are inserted at the intersection of the side and end seals and are effective to close the corner gaps which would otherwise be formed between these seals and form a complete seal with the blade.
A further feature of the present invention resides in an arrangement for aligning or adjusting the position of the blade of the valve on the blade-supporting arms so that the blade runs true to the valve body, the blade slot and to the seals.
It is accordingly an important object of this invention to provide improved side and end seal arrangements for moving blade-type valves for controlling the flow of dry particulate matter.
Another important object of the invention is the provision of seals which are particularly adapted for use with rolling blade type valves of the types shown in my U.S. Pat. Nos. 3,380,475 and 3,556,358, although the particular seal arrangement disclosed herein may be used with flat slide - type gate valves.
A further object of the invention is the provision of a sealing plug to fill the gap at the blade edge between a side seal and a pair of end seals.
A still further object is the provision of an improved double end seal defining a closed air gap which may be pressurized by air from a suitable source.
Another object of the invention is the provision of blade adjusting means by which the position of the blade on the arm may be accurately determined in relation to the side and end seals.
These and other objects and advantages of the present invention will be apparent from the following description, the accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a double or lock-gate valve incorporating the sealing arrangement of my invention;
FIG. 2 is a fragmentary enlarged vertical section through the valve of FIG. 1 showing the improved end and side seals;
FIG. 3 is a further enlarged fragmentary vertical section through one side wall of the valve showing the improved side seals, taken generally along the lines 3--3 of FIG. 2;
FIG. 4 is a fragmentary section showing the relation of the end and side seals, with the side plug seal inserted, looking generally along the line 4--4 of FIG. 2;
FIG. 5 is an elevation view showing also the relation of the end and side seals and showing the side plug seal in exploded relation;
FIG. 6 is an enlarged exploded view showing the relation of the side seal, the end seal, and the side seal plug;
FIG. 7 is a view similar to FIG. 8 but looking at the same parts from a different angle;
FIG. 8 is an enlarged vertical section through the end wall of the valve showing the relation of the side and end seals;
FIG. 9 is a modification of an end seal showing a double end seal arrangement;
FIG. 10 is a perspective view of a modified side seal plug used with the embodiment of FIG. 9;
FIG. 10A shows another form of the side seal;
FIG. 11 is a section taken generally along the line 11--11 of FIG. 9;
FIG. 12 is a fragmentary vertical section showing the side seal as applied to a flat slide type of valve;
FIG. 13 is a fragmentary perspective showing an improved arrangement for mounting a curved blade on the blade support arm;
FIG. 14 is a fragmentary view of the blade and the supporting arm; and
FIG. 15 is an enlarged section through the blade adjusting mechanism taken along the line 15--15 of FIG. 14.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIGS. 1-3, a rotary double-bladed air lock valve which is particularly adapted to make beneficial use of the improved seals of this invention is illustrated generally at 20. The valve 20 includes a valve housing 22 and a pair of arcuate blades 23 and 24 mounted on suitable supporting arms in accordance with the teachings of my U.S. Pat. No. 3,556,358. The valve body 22 is generally rectangular in cross section and may be considered as having a pair of spaced side walls 25, a rear end wall 26 through which the blades 23 and 24 move, and a front end wall 27 (FIG. 2). As fully disclosed in my U.S. Pat. No. '358, the end wall 26 is slotted at transverse regions adjacent the upper and lower ends of the body 22 through which the blades 24 and 23 respectively move within the housing 22 on support arms 28 and 29.
The improved elastomeric top side seals are illustrated generally at 30 in FIGS. 2 and 3 and extend arcuately between the front wall 27 and the back wall 26 of the valve body 22, and include vertical inwardly offset side portions 32 which engage the sides of the respective blades. A depending elastic lip or finger portion 33 is somewhat thinner and more flexible than the side portion 32 and extends downwardly and inwardly from a region adjacent the top of the side portion 32 and engages the top of the respective blade at a region which is inwardly offset from the blade edge. A similar side seal 30a is used for the bottom blade and is of the same cross-sectional configuration as the seal 30. The seals 30 and 30a may be cast or extruded and then curved to the desired blade curvature, or may be cast so as to conform to the curvature of the blade.
Curved seal retainer plates 35 (top) and 35a (bottom) are supported on the side walls by bolts 36 and retain an upper flat portions 38 of the seals 30 and 30a against the respective side walls. The lower end of each seal 30 and 30a is provided with an inwardly extending portion 32' to define a clearance space 40 between the side wall and the portion 32. The vertical portion 32 deflects somewhat with blade movement thereby bringing the finger portion 33 downwardly and into sealing engagement with the upper surface of the blade 23 or 24. In addition, the weight of the material on the blade also engages the finger portion 33 and causes it to deflect or bear against the upper surface of the blade thereby forming an effective seal between the sides of the blade and the side walls of the housing 22. With this arrangement, the blade is sealed along its edge as well as its top surface.
The construction of the end wall seal is illustrated with respect to the upper blade 24, it being understood that an identical seal arrangement is employed with respect to the lower blade 23. Referring to FIGS. 2 and 8, it will be seen that the end wall 26 is inclined to the valve body and is formed with a blade slot 43 through which the blade 24 moves substantially at right angles to the inclined end wall. A pair of essentially identical elastomeric end seals 44 extend from positions on either side of the blade outside of the wall 26 with inwardly turned blade-engaging ends 45 received within the slot 43 and respectively in overlying and underlying relation to the blade. The ends 45 are proportioned to extend a short distance inside the housing 22. The seal retainer plates 46 are held by bolts 47 and are thus external accessible for ease of removal and replacement of the seals.
The end seals 44 extend the full width of the end walls 42 and are cut out or notched as shown at 48 in FIG. 6 to receive the adjacent ends of the side seals 30. The depth of the cut-outs 48 corresponds approximately to the extent to which the seals 44 extend into the interior of the valve housing.
The arrangement of the pairs of end seals 44 with the inwardly turned ends 45 (FIG. 8) extending over the blade 24 and the side seals 30 inevitably results in the formation of a clearance gap at the region of the blade as it passes through the slot 43. For this purpose, an elastomeric end seal plug 50 is employed shown in FIGS. 5-7. The plug 50 is formed with a tapered transversely thin body portion 52 and a transversely thinner locating foot 53. The locating foot 53 is formed with tapered sides 54 adapted to be received within the clearance space 40 defined by the side seal 30, as shown in FIG. 7. The tapered body portion 52 is proportioned to form a close running fit with the side edge of the blade 23 or 24. The portion 52 is formed with upper and lower curved sides 55 which are adapted to be received against the adjacent curved surfaces of the end seals 44, at the curve regions 45 thereof. When inserted, the foot 53 snaps in position inwardly of the cut-out portions 48 and is self-holding by the end seals 44 in this position.
A pair of the end seal plugs 50 are employed for each blade at the opposite sides of each blade. The body portions 52 extend in direction of blade movement between the end seals and side seals for sealing the corner gaps which would otherwise be formed between the side and end seals.
The seals 30, 44 and 50 should be resistant to wear and abrasion and resistant to heat if present and yet should be sufficiently flexible to conform to and bear against the surface of the blade being sealed. Plain and food grade urethane, filled urethanes, silicones and glass or nickel-filled polytetrafluoroethylenes are examples of suitable sealing materials. Flexible metal wipers may be also used for the end seals 44.
A modification of an end wall seal arrangement and modified side seal plug is illustrated in FIGS. 9-11, in which spacers 60 are used to support a pair of secondary blade seals 62 and 63. The seals 62 and 63 are constructed similarly to the seals 44. The spacers 60 set the secondary seals 62 and 63 outwardly of the primary end seals 44 and define therebetween transverse open spaces 65 at locations above and below the blade 24.
A modified end seal plug 70 (FIG. 10) or 70a (FIG. 10A) which has a body portion 72 with outer curved surfaces 73 conforming to the back surfaces of the outer set of seals 62 and 63. The plug 70 has an arrow-shaped portion 74 adapted to be received just inwardly of the inwardly turned ends 75 of the seals 62 and 63. The portions 72 and 74 of the plug 70 are of the same thickness, and when inserted in position as shown in FIG. 9, it is self-holding by reason of engagement of the portion 74 with the seals 62 and 63. The plug 70A may be used in lieu of the plug 70 and has a foot 76 received in the seal recess 40 as in the case of the plug 50, and forms a seal with the side edges of both sets of end seals.
Means for pressurizing the spaces 65 includes a pair of inlets 77 formed through the seals 62 and 63 and leading into the spaces 65, as shown in FIG. 11. Preferably, air under relatively low pressure, but in excess of that in the body itself, may be applied to the inlets 77 to pressurize the spaces 65. This pressure resists any tendency for material under pressure to leak by the primary seals 44 and into the space 65.
The spacers 60 and seal 62 and 63 may be made in one piece, if desired. Preferably, the seals 62 are made of material somewhat softer than that of the seals 44. The retainer plates 46 and the bolts 47' are employed to retain the seal assembly of FIG. 9 against the adjacent end wall in the manner described in connection with the single seal arrangement of FIG. 8.
The improved seals of this invention are not limited in use to valves having curved blades, although they are particularly adapted for use with such valves. They may thus be used with advantage in valves having flat blades commonly known as a flat slide-type valve, an example being illustrated in FIG. 12. In FIG. 12, the side wall 25' of a slide-type valve is illustrated as supporting the side seal 30 in engagement with the flat slide blade 24'. The blade 24' is supported for movement conventionally on side wall-supported rollers 80, one such roller being illustrated in FIG. 12. The improved end seals of FIGS. 8 or 9 may also be used to seal the blade 24' of a slide-type valve.
In order to achieve an effective seal between the surfaces of the blade 24 and the side and end seals, it is important that the blade track accurately along its path of movement and that it be properly positioned against the side seals in its closed position. The traverse and positioning of the blade is even more critical with the use of high durometer abrasion resistant seal materials. Therefore, the invention includes means for adjusting the relative angular position of the blades with respect to the supporting arms.
As shown in FIG. 13, a blade 24 is supported on generally U-shaped arms 28 and is secured thereto by bolts 82. Adjusting means includes two pairs of set screws 86 which extend from a position beneath the arms 28 through tapped openings in the arms into engagement with the adjacent lower surface of the blade 24 at an oblique angle of approximately 45° to blade movement. The set screws 86 bear against the blade lower surface and may be adjusted to vary the tilt and arc of the blade with respect to the arms 28. The blade 24 may then be secured in the adjusted position by tightening the bolts 82 to bring the blade 24 firmly against the set screws 86. In this manner, slight irregularities in the manufacture of the blades, supporting arms, or the pivot points for these arms and slight irregularities in the curvature of the blade itself may be compensated for to assure a proper fit of the blade with both the side seals and the end seals.
While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention.