Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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E~ackground of Invention
This invention relates to an improved high pressure cut-off valvingr device
and is herein disclosed for use in ultra-high pressure water jet cutting systems. The
invention is herein illustra~ively 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 involved.
Instant reliable opening and closing action of the poppet valve controlling
water jet discharge is of vital importance in systems for jet cutting, using water pressures
10 as high as 30,000 psi to 60,000 psi. Automatic or fail-safe normal closure of the valve 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 resultant force holding the valve seated at the extremely high
water pressures used, and that must be overcome to open the valve quickly once it is
closed, a relatively powerful, hence massive valve actuator is typically reguired. This
poses a special problem in terms of risk of accidental opening of the valve, especially with
handheld cutters. For example, even using valve actuator, hydrualic fluid pressures in the
range of 1500 psi to 3000 psi, the actuator required is large and heavy in relation to the
bulk and weight of the small poppet valve. As a result, if the unit dropped on the floor
20 with the valve closed, accidental opening of the valve could occur due to actuator
momentum jerking the valve fom 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 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 or port
surface will be caused by the resultant exeessive closure force.
It is therefore an object of this invention to provide an effective and reliab}e
30 ultra-high pressure valve mechanism including means by which the valve can be quickly
and positively actuated between open and closed positions without damage, is normally
clGsed in fail-safe condition9 and that will remain safely closed against disturbing shocks
or vibrations acting on the unit.
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~ri e~'~escri~on d~ Inven~ion
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According to the present~invention there is provided high-pressure
fluid valve mechanism compr~sing a-valve casing including therein a flow
passage having an inlet, 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 to
move said valve element into and from engagement with said valve seatJ valve
actuator means reciprocable in said valve casing, lost-motion coupling means
connecting said actuator means with said valve carrier includlng means
limiting valve closure movement of said actuator means and spring means inter-
posed between said actuator and said carrier for transmitting a valve-closing '
; force to the valve carrier when said valve actuator is in its limited position,
thereby to close said valve.
Descri~tion'of'Drawin~s
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' In the accompanying drawings, which illustrate an exemplary embodi-
ment of the present invention:
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
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1 at expanded scale showing primarily the valve proper.
20' 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 expan- ;
ded scale showing primarily the valve proper. ' '~
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`:! Detailed Description'of'Preferred'Embodimènt
As illustrated, the ultra-high pressure valve mechanism is designed
~ Qr ~ig~-pressure ~i.e. 3Q,000 psi to 60,Q00 psi), high-velocity (i.e. of the '~
; order o~ 3,000 feet per second) ~ater jet cutting of materials. ~ater at such
pressure received from an intensifier or external sour~e ~not shown) enters
the inlet 10 of valve casing 12 by way vf fitting 14. Passage through the
casi.ng to the discharge jet nozzle 16 is a~forded along the perimeter of
poppet valve assembly 18 in poppet guide chamber 20, along the poppet valve
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22 itself ~hen open, and then through the valve port 24 and connecting pass-
age 26 in seat block 28. A sleeve fitting 30 threa.ded into the discharge end
of the valve casing 12 centers and seals the seating block 28 in the casing
and provides a threaded receptacle for the noz~le f'itting 16. A bevelled
shoulder 28a on the inner end of the seating block bears on thelSl~arp annular
rim 12a of a step in the associated end cavi~y in valve casing 12.
Preferably the closure face of poppet valve element 22 is frusto-
conical as is the complemental seating surface 24 of seating block 28. Pre-
ferably also, as shown in Figures 2 and 4J the cone angle of the seating sur-
face 24 is slightly wider than that of element 22 so that safe tight seatingis assured when the parts are new and not yet worn
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in. As wear-in occurs, the in;tial seating fllong ~n 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 oî sa~ety at the extreme pressures
present.
The valve casing 12 is divided basically into a valve housing portion 12V and a
valve actuator housing 12P. These two, joined at an interface 38, are held together by
four outside corner bolts 40 that rigidify the composite strueture and place the "O" 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 resilliently 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 tlle direction of closing movement of poppet valve 22. 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 actua~or rod 58 threaded at one end into and through
; 20 the body of hdyraulic 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 diseharge 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
30 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 apertures then aligned.
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Hydraulic pressure applied to piston 46 drives it downwardly against spring
~8 to draw valve 22 to the open position (FlGURE 4). Stop 60 lirnits 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-relnxed
position of valve 22 for safety reasons is the closed po~sition. With hydraulic pressure
removed from piston ~6, 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
10 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
light-weight 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 by externally applied shock, is greatly reduced.
An additional object of the present invention not previously mentioned, and
20 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 frictional forces between the seal
71 and the actuator rod 58 are high, a relatively large, hydraulic force is re~uired to move
the rod 58 and vise-versa~ if the seal/rod actuator frictional forces are low, only a small
hdyraulic 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, and 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
30 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.
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The present invention overcomes this problem by ullowing the use at all
times of a hydraulic aetuating pressure to open the valve ancl a return spring force to
close the valve, each sufficiently high to consistently overcome the rod/seal frictional
forces and flt the same time prevent the poppet valve 2~ from becoming overstressed on
elosure. This is accomplished by slidably mounting the poppet carrier on the actuator and
providing an initial seating force via the small spring 66, thus isolating the poppet valve 22
from the closure force of return spring 48 when the valve is seated. Once the poppet
valve is seated, the fluid force acting in ~he valve chamber acting on the poppet carrier - ~ ?
and the valve itself maintains the valve in a seated position until the actuator rod is
lO 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.
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