CA1100386A - Automatic bleeder valve - Google Patents
Automatic bleeder valveInfo
- Publication number
- CA1100386A CA1100386A CA321,946A CA321946A CA1100386A CA 1100386 A CA1100386 A CA 1100386A CA 321946 A CA321946 A CA 321946A CA 1100386 A CA1100386 A CA 1100386A
- Authority
- CA
- Canada
- Prior art keywords
- valve
- counterbore
- vent
- ball
- valve seat
- 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.)
- Expired
Links
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
- F16K24/00—Devices, e.g. valves, for venting or aerating enclosures
- F16K24/04—Devices, e.g. valves, for venting or aerating enclosures for venting only
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Self-Closing Valves And Venting Or Aerating Valves (AREA)
- Fluid-Pressure Circuits (AREA)
- Check Valves (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A vent valve in a hydraulic system opens, when the system is initially pressurized, to allow the escape of air or other gases and closes automatically after the air is expelled when the oil or other operating hydraulic fluid in the system enters the valve because of the greatly increased viscosity of the hydraulic fluid. The main valve member is a ball which is moved upwardly to engage a seat by the hydraulic fluid and the rate of flow around the ball is limited by the diameter of the passage and an inlet orifice to the passage. On the outlet side is a ball check valve which is spring-biased to prevent air from flowing in a reverse direction back into the system, and restricted diameter vents pro pro- a restriction on the flow of air out of the system and aid i preventing premature closing movement of the main valve ball under high volume flow conditions.
A vent valve in a hydraulic system opens, when the system is initially pressurized, to allow the escape of air or other gases and closes automatically after the air is expelled when the oil or other operating hydraulic fluid in the system enters the valve because of the greatly increased viscosity of the hydraulic fluid. The main valve member is a ball which is moved upwardly to engage a seat by the hydraulic fluid and the rate of flow around the ball is limited by the diameter of the passage and an inlet orifice to the passage. On the outlet side is a ball check valve which is spring-biased to prevent air from flowing in a reverse direction back into the system, and restricted diameter vents pro pro- a restriction on the flow of air out of the system and aid i preventing premature closing movement of the main valve ball under high volume flow conditions.
Description
11(}~3~36 This invention relates to a yent valve desi~ned to allow the escape of gases from a hydraulic system, There are many types of hydraulic systems in which problems arise from the entrapment of air or other gases within the system. When part of the space normally taken up by the oil or other hydraulic fluid becomes filled with air or any other gas, the behavior of the system deteriorates because of the compressibility and elasticity of the air when the system is pressurized. This air generally enters the system when the system is depressurized, and is particularly a problem in systems in which the fluid is placed under a less than atmospheric pressure so that a negative pressure differential exists across fluid seals in the system. While this situation is a particular problem with telescoping hydraulic cylinders because of their multiple sliding seals, air can enter other places, such as through the hydraulic reservoir and return lines.
Because the air or other gas naturally rises to the highest part of the system, it has been a common practice to provide a bleeder valve at the high point in the system, which can be manually opened when the system is initially pressurized for operation and then manually closed after the air has been expelled and the valve be~ins to pass hydraulic fluid. Because the valve is located at the high point in the hydraulic system, there are many situations in which access to the vent valve for manual operation is difficult and hazardous, and because it is necessary to determine visually when the air has been expelled and hydraulic fluid is leaking from the bleeder valve, there is a tendency to leak excess amounts of hydraulic fluid, and bm:~l 110(~386 not only must this fluid be replaced in the reservoir from time to time, but because of its nature it tends to attract dirt and other foreiyn material, and therefore requires periodic cleaning of the surrounding area. Furthermore, because of the difficulty in conducting the bleeding operation, which may be necessary as often as every day, and which may require at least two people to do it efficiently, there is a tendency to neglect the bleeding operation and operate the system with a certain amount of entrapped air, which results - 10 in decreased efficiency and even greater wear of certain parts of the hydraulic system.
The present invention provides a vent valve which operates automatically whenever the hydraulic system is pressurized above a certain predetermined, low pressure level well below the operating range to automatically vent any air or other trapped gases to the atmosphere, and as soon as the gases have been expelled and the hydraulic fluid reaches the valve, it automatically closes and seals to prevent any substantial leakage of the hydraulic fluid from the system, According to the valve of the present invention which allows escape of gases from a hydraulic system including a space to be filled with hydraulic fluid under pressure, there is provided a body with first and second chambers in the body and a first passage connecting the first and second chambers.
The first chamber has a restricted inlet connected to the space and a first valve seat connected to the first passage.
A first valve member is provided in the first chamber and is ~~ .~.
~ ~ biased by gravity away from the valve seat. The first valve , _,, member has a density greater than the density of the hydraulic bms~
11003~6 fluid. The second chamber has a second valve seat connected to the first passage, and a second passage connects the second chamber to the atmosphere. A second valve member is provided in the second chamber with means biasing the second valye member against the second valve seat. The first passage spaces the first and second valve seat so that both of the valve members can engage the respective valve seats at the same time.
In a specific embodiment of the invention the body has a bore therein, at the lower end of which is a reduced diameter orifice plate to restrict the flow of any gas or liquid. Above the orifice plate is the first chamber in the form of a cylindrical chamber containing the first valve member in the form of a ball which, if raised to the upper end of the chamber, seals against the first valve seat to prevent fluid flow through the valve. Above the valve seat is the first passage which is a short passage to the second va~ve seat facing in the opposite direction and a second ball forming the second valve member which is adapted to engage this valve seat, by both the force of gravity and a relatively light spring. This second ball lies in the second chamber which is provided with restricted vent openings to the atmosphere, and the end of this chamber is sealed by a plug which is threaded and serves both to adjust the biasing force of the spring and to clamp or force the second ball against its seat to close and prevent operation of the valve if this is desired.
The first ball and the chamber in which it is located .~
are dimensioned such that as air enters the lower orifice plate, it lifts the ball off the orifice plate and flows around the bm ~
3~36 ball throuqh the irst seat to the second hall. r~hen the pressure builds up to a predetermined level such as 5~ psi, the second hall opens to exhaust the air through the vents to the atmosphere. The operation of the first ball is such that it will not rise sufficiently to en~age its seat under the rate of air flow and pressure at which the syste~ operates.
However, as soon as a liquid such as hy~raulic oil enters the orifice plate, its greatly increased viscosity overcomes the weight of the ball and forces it tightly against its valve seat to prevent any leakaae of the oil or hydraulic fluid from the system. The second ball then closes and prevents re-entry of the air into the hydraulic system if the pressure should drop below atmospheric pressure.
The valve is generally mounted in a ~osition close to vertical because of the require~ent of qravity to keep the first ball away from its seat. However, since the valve merely reuuires a sin~le connection to the hydraulic system at a hi~h point, the valve may be mounted in a remote location and connected to the system by a flexible, hydraulic hose.
Because the air or other gas naturally rises to the highest part of the system, it has been a common practice to provide a bleeder valve at the high point in the system, which can be manually opened when the system is initially pressurized for operation and then manually closed after the air has been expelled and the valve be~ins to pass hydraulic fluid. Because the valve is located at the high point in the hydraulic system, there are many situations in which access to the vent valve for manual operation is difficult and hazardous, and because it is necessary to determine visually when the air has been expelled and hydraulic fluid is leaking from the bleeder valve, there is a tendency to leak excess amounts of hydraulic fluid, and bm:~l 110(~386 not only must this fluid be replaced in the reservoir from time to time, but because of its nature it tends to attract dirt and other foreiyn material, and therefore requires periodic cleaning of the surrounding area. Furthermore, because of the difficulty in conducting the bleeding operation, which may be necessary as often as every day, and which may require at least two people to do it efficiently, there is a tendency to neglect the bleeding operation and operate the system with a certain amount of entrapped air, which results - 10 in decreased efficiency and even greater wear of certain parts of the hydraulic system.
The present invention provides a vent valve which operates automatically whenever the hydraulic system is pressurized above a certain predetermined, low pressure level well below the operating range to automatically vent any air or other trapped gases to the atmosphere, and as soon as the gases have been expelled and the hydraulic fluid reaches the valve, it automatically closes and seals to prevent any substantial leakage of the hydraulic fluid from the system, According to the valve of the present invention which allows escape of gases from a hydraulic system including a space to be filled with hydraulic fluid under pressure, there is provided a body with first and second chambers in the body and a first passage connecting the first and second chambers.
The first chamber has a restricted inlet connected to the space and a first valve seat connected to the first passage.
A first valve member is provided in the first chamber and is ~~ .~.
~ ~ biased by gravity away from the valve seat. The first valve , _,, member has a density greater than the density of the hydraulic bms~
11003~6 fluid. The second chamber has a second valve seat connected to the first passage, and a second passage connects the second chamber to the atmosphere. A second valve member is provided in the second chamber with means biasing the second valye member against the second valve seat. The first passage spaces the first and second valve seat so that both of the valve members can engage the respective valve seats at the same time.
In a specific embodiment of the invention the body has a bore therein, at the lower end of which is a reduced diameter orifice plate to restrict the flow of any gas or liquid. Above the orifice plate is the first chamber in the form of a cylindrical chamber containing the first valve member in the form of a ball which, if raised to the upper end of the chamber, seals against the first valve seat to prevent fluid flow through the valve. Above the valve seat is the first passage which is a short passage to the second va~ve seat facing in the opposite direction and a second ball forming the second valve member which is adapted to engage this valve seat, by both the force of gravity and a relatively light spring. This second ball lies in the second chamber which is provided with restricted vent openings to the atmosphere, and the end of this chamber is sealed by a plug which is threaded and serves both to adjust the biasing force of the spring and to clamp or force the second ball against its seat to close and prevent operation of the valve if this is desired.
The first ball and the chamber in which it is located .~
are dimensioned such that as air enters the lower orifice plate, it lifts the ball off the orifice plate and flows around the bm ~
3~36 ball throuqh the irst seat to the second hall. r~hen the pressure builds up to a predetermined level such as 5~ psi, the second hall opens to exhaust the air through the vents to the atmosphere. The operation of the first ball is such that it will not rise sufficiently to en~age its seat under the rate of air flow and pressure at which the syste~ operates.
However, as soon as a liquid such as hy~raulic oil enters the orifice plate, its greatly increased viscosity overcomes the weight of the ball and forces it tightly against its valve seat to prevent any leakaae of the oil or hydraulic fluid from the system. The second ball then closes and prevents re-entry of the air into the hydraulic system if the pressure should drop below atmospheric pressure.
The valve is generally mounted in a ~osition close to vertical because of the require~ent of qravity to keep the first ball away from its seat. However, since the valve merely reuuires a sin~le connection to the hydraulic system at a hi~h point, the valve may be mounted in a remote location and connected to the system by a flexible, hydraulic hose.
2 0 BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects and advantaaes of the invention will be more readily apparent upon an understandina of the preferred e~bodiments of the invention as shown in the drawin~s, wherein:
Fig. 1 is a frao~entary, cross sectional view through a hydraulic cylinder showin~ the mounting of a preferred embodiment of the vent valve of the present invention;
Fig. 2 is a vertical, cross sectional view throuah the vent valve of Fig. 1, showing the valve in the unpressurize~
condition;
bm:i'~
110()3~6 Fia. 3 is a cross sectional view similar to Fi~. 2, but showin~ the valve in a condition where it is venting air from the hydraulic system;
Fig. 4 is a cross sectional view of the valve shown in Figs. 2 and 3, showing the valve closed by hydraulic pressure;
Fig. 5 is a vertical, cross sectional view of another embodiment of the present invention; and Fig. 6 is a schematic view showinq an alternative, remote mounting of the vent valve.
_SCRIPTION OF THE PP~EFERRED F,MBODI~NTS
Referring now to the drawings in greater detail, Fia. 1 shows a typical application of the vent valve of this invention. Shown therein is the fragmentary portion in cross section of the ùpper end of a hydraulic cylinder 10 which has therein a cavity 11 normally adapted to be filled with the operating hydraulic fluid, but which, because it is at the upper end of the system with respect to the forces of gravity, will tend to collect and retain any entrapped air in the system.
The hydraulic cylinder is shown as having a hore or passa~e 12 therein opening into the cavity 11 and adapted to receive the vent valve indicated generally at 13. Outwardly of the bore 12 is a conical seat portion 14, a threaded counterbore 16, and an end face 17 arran~ed to provide venting clearance for the valve when it is assembled into operatin~
position. As shown in Fig. 1, the vent valve 13, in operatinq position, may be tilted a certain distance away from the true vertical, but as will he explained in greater detail hereinafter, for proper operation of the valve as an automatic vent, the vertical axis of the valve member itself preferably should remain ~, , bm:l, 110(~386 within about 60 degrees of the vertical.
The vent valve 13 is shown in qreater detail in Fig. 2, where it can be seen that the valve comprises a hody member 20 which may be machined as a sinale piece from bar stock and at its lower end has a oylindrical outer surface 21 adapted to fit within the bore 12. This outer surface 21 has a groove 22 adapted to receive an O-ring seal 23 and hack-up ring 24 to provide proper sealing engaaement with the bore 1~ to prevent leakage. Above the surface 21 is a conical shoulder 26 adapted to seat aaainst the seat 14 in the hydraulic cylinder to serve as a stop, as well as an additional seal against leakage. Above the shoulder 26 is a threaded portion 27 adapted to engage the threaded counterbore 16 and above that in turn is a reduced diameter vent groove 28 and a wrench receiving hexagonal portion 31. The top end of the body member 20 is defined by an end face 32, and to avoid sharp edges it may be provided with a chamer, as indicated at 33.
At its midpoint, the body member 2b has a central axial bore 35 generally coaxial with the exterior surfaces of the body member, and this bore 35 serves as a flow path between the two valving portions of the vent val~e. At the lower end of bore 35 is a conical valve seat 36, below which is an enlarged counterbore or first chamber 37, which will be seen to have a length approximately e~ual to twice its diameter, for reasons explained in greater detail hereinafter. At the lower end of the counterbore 37 is a second enlar~ed counterhore 38 which receives an orifice plate 40 held in place by a spun-over lip 41 on the end of the body member. The orifice plate has a centrally located orifice opening 43 and a qenerally conical bm:l ~
..
1~003~6 seat portion 44 on its inner surface. A ball or valve member 45 is located within the counterbore 37 and is able to move freely between the seat 44 on orifice plate 40 and the valve seat 36.
At its upper end, the body member 20 has an upper counterbore or second chamber 48 which is connected to the central bore 35 at a conical valve seat 49, Immediately above the valve seat 49 are located a plurality of radial vent passages 51 extending from the upper counterbore 48 to the vent groove 28 on the exterior surface of the body member.
These passages are generally arranged symmetrically around the periphery of the counterbore, but are chosen in number and diameter so as to provide a predetermined flow restriction, as will be explained in greater detail hereinafter.
At its upper end, the upper counterbore 48 connects with a threaded bore portion 53 extending to the end face 32 and a second ball or valve member 55 is positioned within the upper counterbore 48 and adapted to make sealing engagement with the valve seat 49. A plug 56, preferably in the form of a dog point setscrew, is positioned within the threaded bore 53, and is movable axially along the threads to and from the ball 55. The plug 56 is provided with a hex socket 57 for rotation by a wrench and has a conical portion 58 and a central projection 60. The central projection 60 has a flat end face 61 and a biasing spring 63 fits around the central projection 60 to abut at its one end on the conical portion 58 of plug 56 and at its other end against the ball 55, thereby providing a biasing force holding the ball 55 in sealing engagement with ! the valve seat 49. Axial movement of the plug 56 adjusts the bm:,S;
1~0~3~6 force applied by the biasin~ spring 63 to determine the opening force required to move the ball 55 away from valve seat 49. Furthermore, the valve can be positively closed by screwing the plug 56 inwardly until the end face 61 of central projection 60 positively forces the ball 55 against the valve seat 49.
The operation of the vent valve is seen most clearly in connection with Figs. 3 and 4, The vent valve is intended to operate in a generally vertical position (not more than 60 degrees from the vertical)~ although it has been found that the valve will work at an inclination of up to 90 degrees from the vertical. Normally, when the hydraulic system is not pressurized, the valve is in the condition shown in Fig. 2, with the upper ball 55 against its seat to prevent any air entering the system by reverse flow from the vent passages 51 to the central bore 35. The lower ball 45 is normally resting on the conical seat 44 of orifice plate 40~ but it is not necessary that any seal exist at this point, Indeed, the valve is also fully operational if a positive bleed is provided between the seat 44 and the ball 45 by means such as notches in the seat 44 or by making the orifice opening 43 noncircular.
However, whether or not there is a seal at this point does not affec~ the operation of the valve~ since only the force of gravity is holding the ball 45 in this downward position, When the system is pressurized~ the fluid~ whether liquid or gas, lifts the ball 45 off the seat 44~ as generally shown in Fig. 3. Then, when a certain predetermined pressure~
such as 50 psi, is reached, the upper ball 55 moves away from its seat 49 and the fluid is free to pass to the atmosphere bm:¦l through the vent passages 51. As the pressure in the hydraulic system increases, the rate of air or gas flow continues to increase in a generally linear manner, and the ball 45 remains positioned intermediate the orifice plate and the valve seat 36, without making any sealing contact with the latter under these conditions. However, as soon as a liquid begins to enter the valve through the orifice opening 43, the greatly increased viscosity of the liquid, as compared to the gas, now causes the ball 45 to move into sealing engagement with the valve seat 36, as shown in Fig. 4, thereby preventing any further escape of any liquid or hydraulic fluid from the valve, after which the upper ball 55 under the force of biasing spring 63 moves back into sealing engagement with its valve seat 49, Thereafter, as long as some pressure is maintained in the system, the vent valve will remain in the condition shown in Fig, 4 and no fluid, either liquid or gas, will escape from the system.
The exact mode of operation of the valve is not fully understood particularly as to why the ball 45 does not seal against the valve seat 36 even under relatively high rates of flow of air. It has been found, as the result of experimentation, that it is important that the ball 45 be fairly close to the size of the counterbore 37, and that the length of the counterbore 37 be such as to allow the ball 45 to be able to move a distance at least equal to its diameter between the lower position adjacent the orifice seat 44 and the upper position adjacent the valve seat 36. Furthermore, it is important to provide a restriction at the orifice opening 43 and a further restriction downstream of the central bore 35. In tests that have been "~
'~ conducted, the valve has a ball diameter of .375 inches and the bm:~fli .
.
3E~6 diameter of counterbore 37 is 437 inches, Also~ the vent passages 51 are four in number, and are .14Q inches in diameter, Under these conditions, with different diameter orifice openings 43, it has been found that optimum performance is obtained when the orifice opening 43 has a diameter of ,187 inches. A further reduction in size of the orifice opening 43 generally results merely in a decreased rate of air flow at a given pressure level, and an increase in the orifice opening 43 above the optimum can result in premature closing of the valve by engagement of ball 45 against valve seat 36. Thus, when the orifice opening 43 is enlarged to the point of providing substantially no restriction, and the biasing force of spring 63 is adjusted to allow the upper ball 55 to open at 50 psi, it has been found that while air will flow initially, an increase in the pressure to 100 psi will cause the lower ball 45 to seal against the valve seat 36 and prevent further escape of air.
Furthermore, even with the optimum flow at the orifice opening 43 of .187 inches, as described above, removal of the plug 56 and ball 55, which would allow fluid entering the central bore 35 to flow straight ahead to the atmosphere past the threaded bore 53, also causes premature closing of the valve in the same manner as indicated above.
However, if a maximum rate of air flow is not required, the embodiment shown in Fig. 5 can also be employed for the same purpose. The embodiment of Fig. 5 is substantially the same as the embodiment of Figs. 1 through 4, except that the orifice plate 40 is not present. In this embodiment, the lower end has a counterbore 66 of the same diameter as the count~rbore 37, except the counterbore 66 extends all the way . __ bm~
lla~3~6 to the lower end face 67 of the body member 20. To retain the ball 45 in place within the counterbore 66, the body member is provided with a transverse bore 69 which receives a retaining pin 70 against which the ball 45 rests in the lower position. It should be noted that the retaining pin 70 is preferably of such a diameter as to provide a certain amount of flow restriction to prevent premature closing of the ball 45, but it is not as effective in providing high rates of flow as the orifice plate 40 of the embodiment of Figs. 1 to 4~
Fig. 6 shows an alternative mounting arrangement for either of the embodiments of the vent valve for circumstances in which mounting the valve directly in the cylinder would be impractical. In this case, the hydraulic cylinder 72 is provided with a vent fitting 73 which attaches to a flexible hydraulic hose 74. The manifold member 75 is secured remote from the cylinder 72 to a suitable vertical surface, as indicated at 76, by suitable means such as bolt 77. The manifold 75 has a fitting 79 at its lower end to which is connected the other end of the flexible hose 74 and the vent valve of the present invention, as shown at 80, is mounted in a suitable opening on the upper side of the manifold, with its lower end exposed to the fluid entering the manifold through the hose 74.
Although several embodiments of the invention have been shown and described in detail, it should be understood that various modifications and rearrangements may be resorted to without departing from the scope of the invention as defined by the claims.
B
brn: 'I
These and other aspects and advantaaes of the invention will be more readily apparent upon an understandina of the preferred e~bodiments of the invention as shown in the drawin~s, wherein:
Fig. 1 is a frao~entary, cross sectional view through a hydraulic cylinder showin~ the mounting of a preferred embodiment of the vent valve of the present invention;
Fig. 2 is a vertical, cross sectional view throuah the vent valve of Fig. 1, showing the valve in the unpressurize~
condition;
bm:i'~
110()3~6 Fia. 3 is a cross sectional view similar to Fi~. 2, but showin~ the valve in a condition where it is venting air from the hydraulic system;
Fig. 4 is a cross sectional view of the valve shown in Figs. 2 and 3, showing the valve closed by hydraulic pressure;
Fig. 5 is a vertical, cross sectional view of another embodiment of the present invention; and Fig. 6 is a schematic view showinq an alternative, remote mounting of the vent valve.
_SCRIPTION OF THE PP~EFERRED F,MBODI~NTS
Referring now to the drawings in greater detail, Fia. 1 shows a typical application of the vent valve of this invention. Shown therein is the fragmentary portion in cross section of the ùpper end of a hydraulic cylinder 10 which has therein a cavity 11 normally adapted to be filled with the operating hydraulic fluid, but which, because it is at the upper end of the system with respect to the forces of gravity, will tend to collect and retain any entrapped air in the system.
The hydraulic cylinder is shown as having a hore or passa~e 12 therein opening into the cavity 11 and adapted to receive the vent valve indicated generally at 13. Outwardly of the bore 12 is a conical seat portion 14, a threaded counterbore 16, and an end face 17 arran~ed to provide venting clearance for the valve when it is assembled into operatin~
position. As shown in Fig. 1, the vent valve 13, in operatinq position, may be tilted a certain distance away from the true vertical, but as will he explained in greater detail hereinafter, for proper operation of the valve as an automatic vent, the vertical axis of the valve member itself preferably should remain ~, , bm:l, 110(~386 within about 60 degrees of the vertical.
The vent valve 13 is shown in qreater detail in Fig. 2, where it can be seen that the valve comprises a hody member 20 which may be machined as a sinale piece from bar stock and at its lower end has a oylindrical outer surface 21 adapted to fit within the bore 12. This outer surface 21 has a groove 22 adapted to receive an O-ring seal 23 and hack-up ring 24 to provide proper sealing engaaement with the bore 1~ to prevent leakage. Above the surface 21 is a conical shoulder 26 adapted to seat aaainst the seat 14 in the hydraulic cylinder to serve as a stop, as well as an additional seal against leakage. Above the shoulder 26 is a threaded portion 27 adapted to engage the threaded counterbore 16 and above that in turn is a reduced diameter vent groove 28 and a wrench receiving hexagonal portion 31. The top end of the body member 20 is defined by an end face 32, and to avoid sharp edges it may be provided with a chamer, as indicated at 33.
At its midpoint, the body member 2b has a central axial bore 35 generally coaxial with the exterior surfaces of the body member, and this bore 35 serves as a flow path between the two valving portions of the vent val~e. At the lower end of bore 35 is a conical valve seat 36, below which is an enlarged counterbore or first chamber 37, which will be seen to have a length approximately e~ual to twice its diameter, for reasons explained in greater detail hereinafter. At the lower end of the counterbore 37 is a second enlar~ed counterhore 38 which receives an orifice plate 40 held in place by a spun-over lip 41 on the end of the body member. The orifice plate has a centrally located orifice opening 43 and a qenerally conical bm:l ~
..
1~003~6 seat portion 44 on its inner surface. A ball or valve member 45 is located within the counterbore 37 and is able to move freely between the seat 44 on orifice plate 40 and the valve seat 36.
At its upper end, the body member 20 has an upper counterbore or second chamber 48 which is connected to the central bore 35 at a conical valve seat 49, Immediately above the valve seat 49 are located a plurality of radial vent passages 51 extending from the upper counterbore 48 to the vent groove 28 on the exterior surface of the body member.
These passages are generally arranged symmetrically around the periphery of the counterbore, but are chosen in number and diameter so as to provide a predetermined flow restriction, as will be explained in greater detail hereinafter.
At its upper end, the upper counterbore 48 connects with a threaded bore portion 53 extending to the end face 32 and a second ball or valve member 55 is positioned within the upper counterbore 48 and adapted to make sealing engagement with the valve seat 49. A plug 56, preferably in the form of a dog point setscrew, is positioned within the threaded bore 53, and is movable axially along the threads to and from the ball 55. The plug 56 is provided with a hex socket 57 for rotation by a wrench and has a conical portion 58 and a central projection 60. The central projection 60 has a flat end face 61 and a biasing spring 63 fits around the central projection 60 to abut at its one end on the conical portion 58 of plug 56 and at its other end against the ball 55, thereby providing a biasing force holding the ball 55 in sealing engagement with ! the valve seat 49. Axial movement of the plug 56 adjusts the bm:,S;
1~0~3~6 force applied by the biasin~ spring 63 to determine the opening force required to move the ball 55 away from valve seat 49. Furthermore, the valve can be positively closed by screwing the plug 56 inwardly until the end face 61 of central projection 60 positively forces the ball 55 against the valve seat 49.
The operation of the vent valve is seen most clearly in connection with Figs. 3 and 4, The vent valve is intended to operate in a generally vertical position (not more than 60 degrees from the vertical)~ although it has been found that the valve will work at an inclination of up to 90 degrees from the vertical. Normally, when the hydraulic system is not pressurized, the valve is in the condition shown in Fig. 2, with the upper ball 55 against its seat to prevent any air entering the system by reverse flow from the vent passages 51 to the central bore 35. The lower ball 45 is normally resting on the conical seat 44 of orifice plate 40~ but it is not necessary that any seal exist at this point, Indeed, the valve is also fully operational if a positive bleed is provided between the seat 44 and the ball 45 by means such as notches in the seat 44 or by making the orifice opening 43 noncircular.
However, whether or not there is a seal at this point does not affec~ the operation of the valve~ since only the force of gravity is holding the ball 45 in this downward position, When the system is pressurized~ the fluid~ whether liquid or gas, lifts the ball 45 off the seat 44~ as generally shown in Fig. 3. Then, when a certain predetermined pressure~
such as 50 psi, is reached, the upper ball 55 moves away from its seat 49 and the fluid is free to pass to the atmosphere bm:¦l through the vent passages 51. As the pressure in the hydraulic system increases, the rate of air or gas flow continues to increase in a generally linear manner, and the ball 45 remains positioned intermediate the orifice plate and the valve seat 36, without making any sealing contact with the latter under these conditions. However, as soon as a liquid begins to enter the valve through the orifice opening 43, the greatly increased viscosity of the liquid, as compared to the gas, now causes the ball 45 to move into sealing engagement with the valve seat 36, as shown in Fig. 4, thereby preventing any further escape of any liquid or hydraulic fluid from the valve, after which the upper ball 55 under the force of biasing spring 63 moves back into sealing engagement with its valve seat 49, Thereafter, as long as some pressure is maintained in the system, the vent valve will remain in the condition shown in Fig, 4 and no fluid, either liquid or gas, will escape from the system.
The exact mode of operation of the valve is not fully understood particularly as to why the ball 45 does not seal against the valve seat 36 even under relatively high rates of flow of air. It has been found, as the result of experimentation, that it is important that the ball 45 be fairly close to the size of the counterbore 37, and that the length of the counterbore 37 be such as to allow the ball 45 to be able to move a distance at least equal to its diameter between the lower position adjacent the orifice seat 44 and the upper position adjacent the valve seat 36. Furthermore, it is important to provide a restriction at the orifice opening 43 and a further restriction downstream of the central bore 35. In tests that have been "~
'~ conducted, the valve has a ball diameter of .375 inches and the bm:~fli .
.
3E~6 diameter of counterbore 37 is 437 inches, Also~ the vent passages 51 are four in number, and are .14Q inches in diameter, Under these conditions, with different diameter orifice openings 43, it has been found that optimum performance is obtained when the orifice opening 43 has a diameter of ,187 inches. A further reduction in size of the orifice opening 43 generally results merely in a decreased rate of air flow at a given pressure level, and an increase in the orifice opening 43 above the optimum can result in premature closing of the valve by engagement of ball 45 against valve seat 36. Thus, when the orifice opening 43 is enlarged to the point of providing substantially no restriction, and the biasing force of spring 63 is adjusted to allow the upper ball 55 to open at 50 psi, it has been found that while air will flow initially, an increase in the pressure to 100 psi will cause the lower ball 45 to seal against the valve seat 36 and prevent further escape of air.
Furthermore, even with the optimum flow at the orifice opening 43 of .187 inches, as described above, removal of the plug 56 and ball 55, which would allow fluid entering the central bore 35 to flow straight ahead to the atmosphere past the threaded bore 53, also causes premature closing of the valve in the same manner as indicated above.
However, if a maximum rate of air flow is not required, the embodiment shown in Fig. 5 can also be employed for the same purpose. The embodiment of Fig. 5 is substantially the same as the embodiment of Figs. 1 through 4, except that the orifice plate 40 is not present. In this embodiment, the lower end has a counterbore 66 of the same diameter as the count~rbore 37, except the counterbore 66 extends all the way . __ bm~
lla~3~6 to the lower end face 67 of the body member 20. To retain the ball 45 in place within the counterbore 66, the body member is provided with a transverse bore 69 which receives a retaining pin 70 against which the ball 45 rests in the lower position. It should be noted that the retaining pin 70 is preferably of such a diameter as to provide a certain amount of flow restriction to prevent premature closing of the ball 45, but it is not as effective in providing high rates of flow as the orifice plate 40 of the embodiment of Figs. 1 to 4~
Fig. 6 shows an alternative mounting arrangement for either of the embodiments of the vent valve for circumstances in which mounting the valve directly in the cylinder would be impractical. In this case, the hydraulic cylinder 72 is provided with a vent fitting 73 which attaches to a flexible hydraulic hose 74. The manifold member 75 is secured remote from the cylinder 72 to a suitable vertical surface, as indicated at 76, by suitable means such as bolt 77. The manifold 75 has a fitting 79 at its lower end to which is connected the other end of the flexible hose 74 and the vent valve of the present invention, as shown at 80, is mounted in a suitable opening on the upper side of the manifold, with its lower end exposed to the fluid entering the manifold through the hose 74.
Although several embodiments of the invention have been shown and described in detail, it should be understood that various modifications and rearrangements may be resorted to without departing from the scope of the invention as defined by the claims.
B
brn: 'I
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A vent valve to allow escape of gases from a hydraulic system including a space to be filled with hydraulic fluid under pressure, said valve having a body, first and second chambers in said body, a first passage connecting said first and second chambers, said first chamber having a restricted inlet connected to said space and a first valve seat connected to said first passage, a first valve member in said first chamber biased by gravity away from said first valve seat, said first valve member having a density greater than the density of said hydraulic fluid, said second chamber having a second valve seat connected to said first passage, a second connecting said second chamber to the atmosphere, a second valve member in said second chamber, means biasing said second valve member against said second valve seat said first passage spacing said first and second valve seats so that both of said valve members can engage their respective valve seats at the same time.
2. A vent valve as set forth in claim 1, wherein said restricted inlet is a plate having a centrally located circular aperture.
3. A vent valve as set forth in claim 1, wherein said restricted inlet is the open end of said first chamber and a pin extending transversely across said first chamber.
4. A vent valve as set forth in claim 1, wherein said biasing means comprises a helical spring and a plug threadedly mounted in said second chamber.
5. A vent valve as set forth in claim 4, wherein said plug has a central projection to engage said second valve member and force it against said second valve seat to positively close said vent valve by threaded rotation of said plug into said second chamber.
6. A vent valve for a hydraulic system under pressure adapted to open to vent air from said system and to close to prevent the escape of liquid from said system, said valve having a body member, a bore in said body member, a first counterbore at one end of said body member and a second counterbore at the other end of said body member, each of said counterbores being connected to said bore by a valve seat, said body member having a restricted orifice at the end of said first counterbore away from its valve seat to restrict flow of fluid entering said first counterbore, a first valve ball in said first counterbore freely movable between said orifice and said first counterbore valve seat, said first valve ball having a density greater than that of said liquid, a second valve ball in said second counterbore movable to and from said second counterbore valve seat, spring means biasing said second valve ball towards said second counterbore valve seat, and vent passage means connecting said second counterbore with the atmosphere.
7. A vent valve as set forth in claim 6, wherein said orifice is located in a plate secured at the outer end of said first counterbore.
8. A vent valve as set forth in claim 6, wherein said first counterbore has a length to allow said first valve ball to travel a distance of at least one ball diameter between said orifice plate and said first counterbore valve seat.
9. A vent valve as set forth in claim 6, wherein said spring means comprises a helical spring and a plug threadedly mounted in said second counterbore so that threaded movement of said plug in said second counterbore varies the biasing force applied to said second valve ball.
10. A vent valve as set forth in claim 9, wherein said plug has a central projection adapted to engage said second valve ball and force it against said second counterbore valve seat to positively close said vent valve when said plug is threaded inwardly from the outer end of said second counterbore.
11. A vent valve as set forth in claim 6, wherein said vent passage means comprises at least one bore extending radially through said body member adjacent said second counterbore valve seat.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US89306678A | 1978-04-03 | 1978-04-03 | |
US893,066 | 1978-04-03 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1100386A true CA1100386A (en) | 1981-05-05 |
Family
ID=25400982
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA321,946A Expired CA1100386A (en) | 1978-04-03 | 1979-02-20 | Automatic bleeder valve |
CA000426680A Expired CA1163524B (en) | 1978-04-03 | 1983-04-25 | Automatic bleeder valve |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA000426680A Expired CA1163524B (en) | 1978-04-03 | 1983-04-25 | Automatic bleeder valve |
Country Status (7)
Country | Link |
---|---|
JP (1) | JPS54134824A (en) |
BE (1) | BE875276A (en) |
CA (2) | CA1100386A (en) |
DE (1) | DE2912977A1 (en) |
FR (1) | FR2422092A1 (en) |
GB (1) | GB2018399B (en) |
NL (1) | NL7902623A (en) |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2204380A (en) * | 1987-04-09 | 1988-11-09 | Martin John Jolley | Automatic venting device |
DE9201972U1 (en) * | 1992-02-15 | 1993-06-17 | Hydraulik Techniek, Emmen | Pull cylinder |
DE4219663C2 (en) * | 1992-06-16 | 1996-01-18 | Prominent Dosiertechnik Gmbh | Liquid dosing pump |
JPH08282009A (en) * | 1995-04-10 | 1996-10-29 | Canon Inc | Image forming device |
DE19516389A1 (en) * | 1995-05-04 | 1996-11-14 | Fichtel & Sachs Ag | Ventilation element for bore of hydraulic master- or slave-cylinder of motor vehicle |
DE19527666C1 (en) * | 1995-07-28 | 1997-04-03 | Aeg Sensorsysteme Gmbh | Automatic bleed valve for hydraulic systems |
FR2777966B1 (en) * | 1998-04-27 | 2000-05-19 | Coflexip | DIFFERENTIAL VALVE FOR UNDERWATER FLEXIBLE CONDUIT |
DE10101438A1 (en) * | 2001-01-13 | 2002-08-14 | Bayerische Motoren Werke Ag | Ventilation device for hydraulic system of a motor vehicle automatic gearbox, has valve at highest point of hydraulic system with body diameter greater than those of feed and outlet but smaller than valve housing internal diameter |
EP1460026A1 (en) * | 2003-03-18 | 2004-09-22 | Shinn Fu Corporation | Ventilation valve for a hydraulic jack |
US8333217B2 (en) * | 2008-05-28 | 2012-12-18 | Eaton Corporation | Fault-tolerant bleed valve assembly |
DE102008041115A1 (en) * | 2008-08-08 | 2010-02-11 | Zf Friedrichshafen Ag | Hydraulic actuation system for a motor vehicle clutch with a venting device |
DE102011005406A1 (en) * | 2011-03-11 | 2012-09-13 | Zf Friedrichshafen Ag | Device for use as sleeve for initial ventilation of oil- and air-tight hydraulic system of automatic transmission, has ball provided in larger diameter opening of stepped through hole before initial ventilation of hydraulic system |
JP5986414B2 (en) * | 2012-03-30 | 2016-09-06 | 株式会社タダノ | Hydraulic circuit for work machine |
DE102013222979B4 (en) * | 2013-11-12 | 2023-03-30 | Zf Friedrichshafen Ag | Hydraulic system with at least one ventilation device assigned to a cavity |
CN112032146B (en) * | 2020-08-06 | 2023-02-28 | 江苏华浩液压设备有限公司 | Manual and electric integrated hydraulic workstation |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB995919A (en) * | 1962-07-27 | 1965-06-23 | Stuart Grahame Ross | Air bleed valve |
DE1901776C3 (en) * | 1969-01-15 | 1980-04-17 | Ermeto Armaturen Gmbh, 4800 Bielefeld | Device for automatic venting of hydraulic systems |
DE2206765A1 (en) * | 1972-02-12 | 1973-08-16 | Bosch Gmbh Robert | VENTILATION DEVICE FOR HYDRO SYSTEMS |
JPS4915301U (en) * | 1972-05-15 | 1974-02-08 | ||
FR2187711A1 (en) * | 1972-06-15 | 1974-01-18 | Air Liquide | |
JPS5212910Y2 (en) * | 1972-07-12 | 1977-03-23 | ||
DD124827A1 (en) * | 1976-03-17 | 1977-03-16 |
-
1979
- 1979-02-20 CA CA321,946A patent/CA1100386A/en not_active Expired
- 1979-03-28 GB GB7910831A patent/GB2018399B/en not_active Expired
- 1979-03-31 DE DE19792912977 patent/DE2912977A1/en not_active Ceased
- 1979-04-02 FR FR7908214A patent/FR2422092A1/en active Granted
- 1979-04-02 BE BE6/46794A patent/BE875276A/en not_active IP Right Cessation
- 1979-04-03 JP JP4025179A patent/JPS54134824A/en active Granted
- 1979-04-03 NL NL7902623A patent/NL7902623A/en not_active Application Discontinuation
-
1983
- 1983-04-25 CA CA000426680A patent/CA1163524B/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
BE875276A (en) | 1979-07-31 |
GB2018399B (en) | 1982-05-12 |
GB2018399A (en) | 1979-10-17 |
JPS6333593B2 (en) | 1988-07-06 |
FR2422092B1 (en) | 1983-03-11 |
NL7902623A (en) | 1979-10-05 |
FR2422092A1 (en) | 1979-11-02 |
DE2912977A1 (en) | 1979-10-04 |
JPS54134824A (en) | 1979-10-19 |
CA1163524B (en) | 1984-03-13 |
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MZSU | Surrender | ||
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