GB1560043A - Valve mechanism for controlling high pressure fluid - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO VALVE MECHANISM FOR CONTROLLING HIGH PRESSURE FLUID (71) We, FLOW INDUSTRIES, INC., a Corporation organised and existing under the Laws of the State of Washington, United States of America of Post Office Box 5040, Kent, Washington 98031, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement : This invention relates to an improved high pressure cut-off valving device and is herein disclosed for use in ultra-high pressure water jet cutting systems.The invention is herein illustratively described by reference to the presently preferred embodiment thereof; however, it will be recognized that certain modifications and changes may be made therein with respect to details without departing from the essential features claimed.

Instant reliable opening and closing action of the valve element controlling water jet discharge is of vital importance in systems for iet cutting, using water pressures as high as 30,000 psi to 60,000 psi. Automatic or fail-safe normal closure of the valve element is also important for safety in such apparatus, so as to avoid risk of injury to persons and damage to objects and work materials at the extremely high cutting pressures used.

In view of the extremely high pressure of water holding the valve element seated and friction in the movable parts, a relatively powerful, hence massive valve actuator is typically required to overcome the resultant force on the valve element so that it opens quickly. This poses a special problem in terms or risk of accidental opening of the valve element, especially with handheld cutters. For example, even using valve actuator. hydraulic fluid pressures in the range of 1500 psi to 3000 psi, the actllator required is large and heavy in relation to the bulk and weight of the small valve element.

As a result, if the unit dropped on the floor with the valve closed, accidental opening of the valve could occur due to actuator momeiirnm jerking the valve element from its seat on impact. Moreover, and perhaps more importantly, with the extremely high operating pressures to be sealed in the valve chamber the sealing device for the valve actuator rod imposes a degree of friction on the rod that is variable and at times high.

As a consequence, if force is exerted by an actuator directly on the valve element to force it reliably to a seat, that force must be high enough to readily overcome the frictional restraint when it is at its highest level. There is then the likelihood when the frictional restraint is low that damage to the valve element or port surface will be caused by the resultant excessive closure force.

It is therefore an object of this invention to provide an effective and reliable ultrahigh pressure valve mechanism including means by which the valve element can be quickly and positively actuated between open and closed positions without damage, is normally closed in fail-safe condition, and that will remain safely closed against disturbing shocks or vibrations acting on the unit.

According to the invention tllere is provided a valve mechanism for controlling nozzle discharge in a high pressure liquid jet cutting nozzle device said mechanism comprising a valve casing including therein a flow passage having an inlet for high pressure liquid and an outlet having a valve port with a seat, and a valve chamber adjoining said port, a valve member including a valve element and valve element carrier means, guided for movement in said valve chamber into and from engagement with said valve seat, valve actuator means including an actuator reciprocable in said valve casing outside of said chamber, lost-motion coupling means connecting said actuator means with said valve element carrier means including rod means coupled to the actuator and slidably entering said valve chamber through a frictional seal in said casing, a spring member interposed operatively between said rod means and said valve element carrier means for transmitting valve-closing force to the valve element carrier means in one direction of actuator movement, means positively limiting actuator movement in said one direction to seat the valve element thereby indirectly through force of said spring, and co-operable abutment means on said rod means and valve element carrier means interengageable for effecting positive retraction of said carrier and opening of the valve after an initial lost-motion of the rod means during reverse movement of the actuator.

As herein disclosed, the invention features a poppet valve element on a carrier that is coupled to a valve actuator through a lost-motion connection. A bias spring in the connection is compressed to provide a bias force tending to close the valve element when the actuator shifts under recoil force of its return spring in the direction to close the valve.

These and other features, objects and advantages of the invention will become more fully evident from the following description by reference to the preferred embodiment depicted in the drawings in which: Figure 1 is a longitudinal sectional view of the valve assembly with the valve in closed position; and Figure 2 is a fragmentary portion of Figure 1 at expanded scale showing primarily the valve proper.

Figure 3 is a view similar to Figure 1 with the valve open: and Figure 4, similar to Figure 2, is a fragmentary portion of Figure 3 at expanded scale showing primarily the valve proper.

As illustrated, the ultra-high-pressure valve mechanism is designed for hiFhfpres- sure (i.e. 30,000 psi to 60,000 psi), highvelocity (i.e. of the order of 3,000 feet per second) water jet cutting of materials. Water at such pressure received from an intensifier or external source (not shown) enters the inlet 10 of valve casing 12 by way of fitting 14. Passage through the casing to the discharge jet nozzle 16 is afforded along the perimeter of poppet valve assembly 18 in poppet guide chamber 20, along the poppet valve element 22 itself when open, and then through the valve port 24 and connecting passage 26 in seat block 28. A sleeve fitting 30 threaded into the discharge end of the valve casing 12 centers and seals the seating block 28 in the casing and provides a threaded recentacle for the nozzle fitting 16.

A bevelled shoulder 28a on the inner end of the seating block bears on the sharp annular rim 12a of a step in the associated end cavitv in valve casing 12.

Preferably the closure face of poppet valve element 22 is frusto-conical as is the complemetnal seating surface 24 of seating block 28. Preferably also, as shown in Figures 2 and 4, the cone angle of the seating surface 24 is slightly wider than that of element 22 so that safe tight seating is assured when the parts are new and not yet worn in. As wear-in occurs, the initial seating along an edge of contact spreads progressively into a widening annular zone of contact between the cone surfaces, still assuring leak-tight closure of the valve as necessary for reasons of safety at the extreme pressure present.

The valve casing 12 is divided basically into a valve housing portion 12tut and a valve actuator housing 12P. These two, joined at an interface 38, are held together by four outside coroner bolts 40 that rigidify the composite structure and place the "0" ring seal 42 between portions 12V and 12P in compression at the interface between them.

Within actuator housing 12P, and formed by a sealed tubular sleeve portion 44a thereof, is a cylindrical chamber 44 accommodating the cooperating valve actuation hydraulic piston 46 and piston return spring 48. Of any suitable type, such as that comprising a stack of resiliently compressible cupped washers, spring 48 is socketed against the closed end of chamber 44 where it bears on the fixed end plate 50 from which it can react against the adjacent face of hydraulic valve actuator piston 46 to urge the latter in the direction of closing movement of poppet valve element 22, the piston 46 abutting the actuator housing block at its upper limiting position in chamber 44.

Hydraulic fluid under pressure, provided and controllable by means not shown herein, is delivered into the opposed end of piston chamber 44 through a fitting 52 and by way of a connecting lateral passage 54 and axial passage 56 in the actuator housing block.

Through this central or axial passage also extends a valve actuator rod 58 threaded at one end into and through the body of hydraulic piston 46 and into the central cylindrical boss 46a. The latter projects axially from the piston face through the aligned openings in the washer springs 48 to an extent that its free end can serve as a stop. As such it is engageable with an adjustable stop bolt 60 threaded through plate 50 into the end of cavity 44.

High pressure water leaking past actuator seals 71 is collected and drained off through a discharge fitting 80.

The opposite end of actuator rod 58 projects into poppet assembly guide chamber 20 where it passes slidably through an end opening and into the cylindrical interior chamber 62a in poppet carrier 62. Within the chamber 62a, the rod tip is connected by threaded engagement with head 64 freely slidable in the chamber. Key 64a prevents loosening of the connection. Helical spring 66 is interposed between head 64 and the inner end of the base 68 of poppet valve element 22. Base 68 in turn is threaded a precise distance into sliding valve carrier 62 where it is locked by a pin 70 inserted through anertures then aligned.

Hydraulic pressure applied to piston 46 drives it downwardly against spring 48 to draw valve 22 to the open position (Figure 4). Stop 60 limits the stroke. Before such limit is reached head 64 bearing against the end wall of valve carrier 62 assures positive opening of the poppet valve. However the desired normal or system-relaxed position of valve 22 for safety reasons is the closed position. With hydraulic pressure removed from piston 46, the latter is automatically advanced by return spring 48 to its upper limiting position in chamber 44, which produces return movement of rod head or abutment 64. Such shifting of the actuator rod head frees the poppet valve assembly 22, 68, 62 to move to the valve-closed position.While water pressure acting on the valve carrier 62 tends to return the valve 22 to its seat without other assistance, inherent self-closing is not sufficiently reliable by that means alone. Bias spring 66 is therefore utilized to urge the valve to its seat when the actuator rod 58 is in its spring-returned position. Compression stress in the bias spring then exists due to the seating of valve 22 before completion of the return stroke of actuator rod 58.

By thus utilizing a normally valve-closed design and a relatively small and lightweight poppet valve assembly coupled by the lost-motion connection to the heavier hydraulic piston actuator, the danger of accidental opening of the high pressure water jet valve 22, such as under conditions of externally applied shock and vibration, is greatly reduced and rapid opening and assured closure of the valve are aided.

An additional obiect of the present invention not previously mentioned, and perhaps the most important, is the provision of a high pressure valve seating mechanism that overcomes prior art problems associated with inconsistently variable seal forces between the actuator rod 58 and the rod seal 71. If the friction forces between the seal 71 and the actuator rod 58 are high, a relatively large, hydraulic force is required to move the rod 58 and vise-versa; if the seal/rod actuator frictional forces are low, only a small hydraulic force is necessary to move the rod.

In prior art high pressure valves, the actuator rod is rigidly affixed to the valve element 22. In such prior art devices, if a high hydraulic pressure is supplied to move the rod, at the same time the seal/rod frictional forces are low, the force with which the poppet valve 22 engages its seat is relatively high, causing an overstressing of the valve and probable short term failure of the valve. To the contrary, if only a small hydraulic pressure is employed to move the actuator rod 58 and the seal/actuator rod frictional forces are high, the actuator rod will be prevented from moving, thereby rendering the valve inoperable.

The present invention overcomes this problem by allowing the use at all times of a hydraulic actuating pressure to open the valve and a return spring force to close the valve, each sufficiently high to consistently overcome the rod/seal frictional forces and at the same time prevent the poppet valve 22 from becoming overstressed on closure.

This is accomplished by slidably mounting the poppet carrier on the actuator rod and providing an initial seating force via the small spring 66. thus isolating the poppet valve element 22 from the closure force of return spring 48 when the valve is seated.

Once the poppet valve element is seated, the fluid force acting in the valve chamber acting on the poppet carrier and the valve itself maintains the valve in a seated position until the actuator rod is retracted by piston 46 to open the valve.

Having thus described the preferred embodiment of this invention, it should be understood that the inventive concepts may be practiced in varying equivalent forms and applications within the intended scope of the appended claims.

WHAT WE CLAIM IS:- 1. A valve mechanism for controlling nozzle discharge in a high pressure liquid jet cutting nozzle device said mechanism comprising a valve casing including therein a flow passage having an inlet for high pressure liquid and an outlet having a valve port with a seat, and a valve chamber adjoining said port, a valve member including a valve element and valve element carrier means, guided for movement in said valve chamber into and from engagement with said valve seat, valve actuator means including an actuator reciprocable in said valve casing outside of said chamber, lost-motion coupling means connecting said actuator means with said valve element carrier means including rod means coupled to the actuator and slidably entering said valve chamber through a frictional seal in said casing, a spring member interposed operatively between said rod means and said valve element carrier means for transmitting valve-closing force to the valve element carrier means in one direction of actuator movement, means positively limiting actuator movement in said one direction to seat the valve element thereby indirectly through force of said spring, and co-operable abutment means

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. loosening of the connection. Helical spring 66 is interposed between head 64 and the inner end of the base 68 of poppet valve element 22. Base 68 in turn is threaded a precise distance into sliding valve carrier 62 where it is locked by a pin 70 inserted through anertures then aligned. Hydraulic pressure applied to piston 46 drives it downwardly against spring 48 to draw valve 22 to the open position (Figure 4). Stop 60 limits the stroke. Before such limit is reached head 64 bearing against the end wall of valve carrier 62 assures positive opening of the poppet valve. However the desired normal or system-relaxed position of valve 22 for safety reasons is the closed position. With hydraulic pressure removed from piston 46, the latter is automatically advanced by return spring 48 to its upper limiting position in chamber 44, which produces return movement of rod head or abutment 64. Such shifting of the actuator rod head frees the poppet valve assembly 22, 68, 62 to move to the valve-closed position.While water pressure acting on the valve carrier 62 tends to return the valve 22 to its seat without other assistance, inherent self-closing is not sufficiently reliable by that means alone. Bias spring 66 is therefore utilized to urge the valve to its seat when the actuator rod 58 is in its spring-returned position. Compression stress in the bias spring then exists due to the seating of valve 22 before completion of the return stroke of actuator rod 58. By thus utilizing a normally valve-closed design and a relatively small and lightweight poppet valve assembly coupled by the lost-motion connection to the heavier hydraulic piston actuator, the danger of accidental opening of the high pressure water jet valve 22, such as under conditions of externally applied shock and vibration, is greatly reduced and rapid opening and assured closure of the valve are aided. An additional obiect of the present invention not previously mentioned, and perhaps the most important, is the provision of a high pressure valve seating mechanism that overcomes prior art problems associated with inconsistently variable seal forces between the actuator rod 58 and the rod seal 71. If the friction forces between the seal 71 and the actuator rod 58 are high, a relatively large, hydraulic force is required to move the rod 58 and vise-versa; if the seal/rod actuator frictional forces are low, only a small hydraulic force is necessary to move the rod. In prior art high pressure valves, the actuator rod is rigidly affixed to the valve element 22. In such prior art devices, if a high hydraulic pressure is supplied to move the rod, at the same time the seal/rod frictional forces are low, the force with which the poppet valve 22 engages its seat is relatively high, causing an overstressing of the valve and probable short term failure of the valve. To the contrary, if only a small hydraulic pressure is employed to move the actuator rod 58 and the seal/actuator rod frictional forces are high, the actuator rod will be prevented from moving, thereby rendering the valve inoperable. The present invention overcomes this problem by allowing the use at all times of a hydraulic actuating pressure to open the valve and a return spring force to close the valve, each sufficiently high to consistently overcome the rod/seal frictional forces and at the same time prevent the poppet valve 22 from becoming overstressed on closure. This is accomplished by slidably mounting the poppet carrier on the actuator rod and providing an initial seating force via the small spring 66. thus isolating the poppet valve element 22 from the closure force of return spring 48 when the valve is seated. Once the poppet valve element is seated, the fluid force acting in the valve chamber acting on the poppet carrier and the valve itself maintains the valve in a seated position until the actuator rod is retracted by piston 46 to open the valve. Having thus described the preferred embodiment of this invention, it should be understood that the inventive concepts may be practiced in varying equivalent forms and applications within the intended scope of the appended claims. WHAT WE CLAIM IS:-

1. A valve mechanism for controlling nozzle discharge in a high pressure liquid jet cutting nozzle device said mechanism comprising a valve casing including therein a flow passage having an inlet for high pressure liquid and an outlet having a valve port with a seat, and a valve chamber adjoining said port, a valve member including a valve element and valve element carrier means, guided for movement in said valve chamber into and from engagement with said valve seat, valve actuator means including an actuator reciprocable in said valve casing outside of said chamber, lost-motion coupling means connecting said actuator means with said valve element carrier means including rod means coupled to the actuator and slidably entering said valve chamber through a frictional seal in said casing, a spring member interposed operatively between said rod means and said valve element carrier means for transmitting valve-closing force to the valve element carrier means in one direction of actuator movement, means positively limiting actuator movement in said one direction to seat the valve element thereby indirectly through force of said spring, and co-operable abutment means

on said rod means and valve element carrier means interengageable for effecting positive retraction of said carrier and opening of the valve after an initial lost-motion of the rod means during reverse movement of the actuator.

2. A valve mechanism according to Claim 1, wherein said actuator means comprises hydraulic piston and cylinder means, the valve element carrier means comprising a hollow cylindrical element carrying the valve element thereon, the rod extending slidably into said hollow cylindrical element through one end thereof and having a head forming abutment means thereon longitudinally slidable in said hollow cylindrical member, and wherein the spring member is interposed between said head and one end of said cylindrical member.

3. A valve mechanism according to Claim 2, wherein the valve element and the valve seat comprise mutually complemental conically tapered surfaces, the cone angle of the valve seat being wider than that of the valve element.

4. A valve mechanism according to Claim 1, wherein the mass of the valve actuator means is several times that of the valve member.

5. A valve mechanism according to Claim 4. wherein the valve casing flow passage includes an inlet extending into the valve chamber adiacent the end thereof opposite from the valve seat.

6. A valve mechanism according to Claim 1. wherein the valve casing flow passage in cludes an inlet extending into the valve chamber adiacent the end thereof opposite from the valve seat.

7. A valve mechanism for controlling nozzle discharge in a high pressure liquid jet cutting nozzle device said mechanism comprising a valve casing including therein a flow passage having an inlct for high pressure liquid, an outlet having a valve port with a seat, and a valve chamber adjoining said port, a valve member including a valve element and valve element carrier means, guided for movement in said valve chamber into and from engagement with said valve seat, valve actuator means reciprocable in said valve casing, lost-motion coupling means connecting said actuator means with said valve element carrier means including means limiting valve closure movement of said actuator means and spring means interposed between said actuator and said valve element carrier means for transmitting a valveclosing force to the valve element carrier means when said valve actuator is in its limited position, thereby to close said valve.

8. A valve mechanism according to Claim 7, wherein the valve element carrier means is so formed and the valve casing flow passage includes an inlet extending into the valve chamber at a location whereby highpressure liquid entering through said inlet exerts added valve-closing pressure on said valve element carrier means with the valve element seated.

9. A valve mechanism substantially as described hereinbefore with reference to and as illustrated in the accompanying drawings.