Abstract:
In a pilot-operated valve having a valve body, including inlet and outlet portions controllably interconnected via a main piston bore portion; a main piston movable within the main piston bore; an operator portion; an operator assembly including a movable plunger assembly; and an actuating mechanism for actuating the plunger assembly, wherein the improvement comprises a further bore located within the valve body and a manually-operated override assembly retained therein, including a stem having a tool actuating portion; a cam portion extending radially into the operator bore portion and, upon a first predetermined rotation physically actuating the plunger assembly; and an actuating surface extending tangentially into the main piston bore portion which, upon a second rotation physically actuates the main piston. A method of actuating the manual override assembly is also set forth.

Description:
CROSS-REFERENCE TO RELATED CASES 
   The present application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 60/442,733 filed Jan. 24, 2003, and U.S. Provisional Application Ser. No. 60/447,241 filed Feb. 13, 2003, the disclosures of which are incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention pertains to pilot-operated valves, specifically to manually actuated override assemblies used in valves, such as remote pilot-operated valves and the methods used for operating same. 
   BACKGROUND OF THE INVENTION 
   Among typical applications for remote pilot-operated valves, such as for automatic temperature, pressure and time switches, and particularly as solenoid valves, are refrigeration systems where they are often utilized for evaporator temperature control, defrost pump down and heat reclaim systems, for example. 
   A solenoid valve is an electronically operated device used to control the flow of liquids or gases in a positive, fully-closed or fully open mode. When energized, the solenoid coil provides a strong magnetic force which pulls a steel plunger up into the plunger tube thus opening up the valve orifice in a normally closed valve, thereby permitting the flow of liquids or gases. Pilot-operated valves are among the most widely used solenoid valves. 
   For servicing and maintenance purposes it is desirable that the normally remotely controlled pilot-operated valves be capable of being opened and closed manually. This is generally accomplished via manual override assemblies or mechanisms built into the valve assemblies. Generally such assemblies, in main piston type valves, take the form of cylindrical plugs that are manually threaded up from under the main valve piston and forcing same off its seating at high force load. A typical prior art construction of this type is set forth in U.S. Pat. No. 3,236,494 to Frantz. Other prior art structures often use rotatable plunger and cam mechanisms of the type typically set forth in U.S. Pat. No. 4,501,299 to Klimowicz et al.; U.S. Pat. No. 4,643,393 to Kogusi et al.; U.S. Pat. No. 4,916,437 to Gazzaz; and U.S. Pat. No. 5,285,814 to Pettersson et al. In the structure set forth in U.S. Pat. No. 5,271,599 to Kolchinsky et al., a cam-actuated control rod extends from the top of the valve through the solenoid sleeve to accomplish the override function. 
   However, none of these prior art constructions incorporate the dual purpose of overriding both the operator (such as a solenoid) and the main piston of a piston-type pilot-operated valve. 
   SUMMARY OF THE INVENTION 
   A feature of the present invention is to provide an improvement in a pilot-operated valve having a valve body, including inlet and outlet portions controllably interconnected via a main piston bore portion having a first orifice; a main piston sealingly movable within the main piston bore in a normally biased sealing relationship relative to the first orifice; and an operator portion, having a second orifice, perpendicular to the main piston bore portion, controllably interconnected with the main piston bore and outlet portions. An operator assembly connected with the operator bore portion, includes a movable plunger assembly normally biased into a sealing relationship relative to the second orifice, thereby blocking the communication between the main piston bore and the outlet portion. An actuating mechanism is provided for controllably actuating the plunger assembly away from the sealing relationship relative to the second orifice, with the second orifice and the plunger assembly cooperating to serve as a pilot portion of the valve. The improvement comprises the addition of a further generally cylindrical bore located within the valve body substantially perpendicular as well as tangential to the main piston bore portion and being perpendicular as well as radial to the operator bore portion. An override assembly is sealably and rotationally controllably retained within this further bore, the assembly including a generally cylindrical stem having a manually-operated sealed tool actuating portion on one end thereof; a sealed cam portion, on the other end of the stem, extending radially into the operator bore portion and, upon a first predetermined extent of rotation of the stem, physically separating the plunger assembly from the sealing relationship with the second orifice. An actuating surface on the stem extends tangentially into the main piston bore portion and, upon a second predetermined extent of rotation of the stem, physically separates the main piston from the sealing relationship with the first orifice. 
   Other features of the improved pilot-operated valve are that the noted actuating surface is located between the tool actuation portion and the cam portion; that the first and second predetermined extents of rotation are sequential; that the first and second predetermined extents of rotation are each about 90 degrees; and that first and second predetermined extents of rotation are adjacent and substantially sequential. 
   A further feature of this invention is that, when said valve is not under pressure, the manual override assembly sequentially separates the plunger assembly and the main piston valve from their respective sealing relationships in one continuous about 180 degree rotation. 
   In another feature, the pilot-operated valve, depending upon the direction of rotation of the stem actuating surface and, depending upon whether the valve is under pressure, either blocks the piston from the sealing relationship with the first orifice or separates the main piston from the sealing relationship with the first orifice. 
   In yet an additional feature of this invention, the override assembly stem further includes a rotation-directing limiting portion, for the cam portion, which is located intermediate the cam portion and the actuation surface. 
   Another feature of the present invention includes a method for actuating the improved pilot-operated valve of this invention wherein this valve has a valve body including inlet and outlet portions controllably interconnected via a main piston bore having a first orifice; a main piston sealingly movable within the main piston bore in a normally biased relationship relative to the first orifice; and an operator portion, having a second orifice, perpendicular to the main piston bore portion, controllably interconnected with the main bore and outlet portions. An operator assembly is connected with the operator bore portion and includes a movable plunger assembly normally biased into a sealing relationship relative to the second orifice. An actuating assembly is utilized for controllably actuating the plunger assembly, with the second orifice and the plunger assembly cooperating to serve as a pilot portion of the valve. A further generally cylindrical bore, located within the valve body, is substantially perpendicular as well as tangential to the main piston bore portion and is perpendicular as well as radial to the operator bore portion. An override assembly is sealably retained within the further bore, the override assembly including a generally cylindrical stem having a sealed tool actuating portion on one end thereof, a sealed cam portion on the other end thereof which extends radially into the operator bore portion, and an actuating surface on the stem that extends tangentially into the main piston bore portion. The method comprising the steps of: manually rotating the tool actuating portion for a predetermined extent of rotation of the override assembly; physically separating the plunger assembly from its sealing relationship with the second orifice during a first portion of the predetermined extent of rotation; and physically separating the main piston from its sealing relationship with the first orifice during a second portion of the predetermined extent of rotation. 
   Other features of the method for actuating the improved pilot-operated valve of this invention include that the said first and second portions of the predetermined extent of rotation are adjacent and sequential; that the first and second portions of the predetermined extent of rotation are each about 90 degrees; and wherein the predetermined extent of rotation consists of one continuous about 180 degree rotation of the override assembly. 
   Another feature of the method for actuating the improved pilot-operated valve of this invention is that, when the valve is not under pressure, the noted manual rotating of the tool actuating portion sequentially physically separates the plunger assembly and the piston valve from their respective sealing relationships in one continuous about 180 degree rotation encompassing both the first and second portions of the predetermined extent of rotation; and wherein, depending upon the direction of manual rotating of the stem actuating surface and, depending upon whether the valve is under pressure, either blocks the piston from the sealing relationship with the first orifice or separates the main piston from the sealing relationship with the first orifice during the second portion of the predetermined extent of rotation. 
   Finally, in the method for actuating the improved pilot-operated valve of this invention, the first portion of the predetermined extent of rotation further includes another portion of the stem for limiting the rotation-direction of the cam portion. 
   The foregoing advantages, construction and method of operation of the present invention will become more readily apparent from the following description in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top plan of a valve incorporating the manual override assembly of this invention. 
       FIG. 2  is an enlarged longitudinal vertical cross-sectional view of the valve of  FIG. 1 , taken along line A—A thereof showing a longitudinal section of the manual override assembly. 
       FIG. 3  is an elevational side view of the valve of this invention. 
       FIG. 4  is an enlarged lateral cross-sectional view of the valve of  FIG. 3 , taken along line B—B thereof showing a transverse section of the manual override valve assembly. 
       FIG. 5  is an enlarged sectional view, taken along line  5 — 5  of  FIG. 3 , showing the pilot orifice cavity and a horizontal cross-sectional view of the manual override stem. 
       FIG. 6  is an exploded view of the valve of this invention, particularly the manual override assembly. 
       FIG. 7  is a perspective view of the override stem of the manual override assembly of this invention. 
       FIG. 8  is an end view of the override stem of FIG.  7 . 
       FIG. 9  is a longitudinal cross-sectional view, taken along line A—A of FIG.  8 . 
       FIG. 10  is a view of the area defined within broken circle line  10 — 10  of  FIG. 9 , showing a 22 degree clockwise off-set, relative to that of  FIG. 9 , taken along line B—B of FIG.  8 . 
       FIG. 11  is a full longitudinal view of the section shown in FIG.  9 . 
       FIG. 12  is an enlarged transverse sectional view taken along line E—E of FIG.  11 . 
       FIG. 13  is an enlarged transverse sectional view taken along line C—C of FIG.  11 . 
   

   Similar numerals refer to similar parts throughout the several drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
   Moreover, the description and illustration of the invention is but an example and the invention is not limited to the exact details shown and described. 
   As part of the noted detailed description, a brief reference will initially be made relative to the operation of a remote pilot-operated valve. The relationship between a P1 inlet pressure, a P2 outlet pressure and a P3 pressure behind the main orifice piston, is the key to understanding how such a valve operates. When the valve is closed, i.e., when the main orifice piston blocks the main orifice between the valve inlet and the valve outlet, P3 is equal to P1 because pressurized fluid is able to flow to the backside of the piston through at least one equalizer hole. The piston seals off the main orifice by force exerted, via a spring, on the backside of the piston, with P2 thus being less than P1. A pilot orifice is sealed by the plunger of a remote controlled operator, such as a solenoid operator, thus preventing P3 pressure from exhausting to the valve outlet portion. 
   When it is desired to open the closed valve, the remote operator is actuated and, in the case of a solenoid operator, the magnetic plunger is lifted off the pilot orifice by magnetic force. Pressurized fluid, on the backside of the piston is thereafter exhausted through the pilot orifice into the valve outlet portion. Since the pilot orifice opening is considerably larger than the piston equalizer hole, pressurized fluid is exhausted from the backside of the piston faster than the pressurized fluid entering through the equalizer hole, with the rapid exhausting of the backside of the piston causing P3&lt;P1. The resulting difference between P3 and P1 is sufficient that the resultant force on the piston overcomes the spring force, thereby displacing the piston off the main orifice, and enabling pressurized fluid to flow through the main orifice, i.e., permitting such fluid flow directly from the valve inlet portion to the valve outlet portion. Those persons skilled in the art will appreciate that this typical valve operation also applies to the operation of the valve of this invention. 
   Turning now to the drawings, and particularly to  FIGS. 1-6 , there is shown a remote pilot-operated valve  20  having a manual override assembly  80 , which will be discussed in more detail relative to  FIGS. 7-12 . Basically, valve  20  takes the form of a remote pilot-operated piston-type solenoid valve having a valve body  22  including an inlet portion  24  and an outlet portion  26 , separated by a main piston bore portion  28  as well as including an operator bore portion  30 . Valve body  22  is machined with the operator bore portion  30  and main piston bore portion  28  being at 90 degrees to each other, with operator bore portion  30  also being longitudinally offset, relative to main piston bore portion  28 , as best seen in FIG.  6 . An arcuate internal bore  32 , best seen in  FIGS. 4 and 5 , connects main piston bore portion  28  with operator bore portion  30 . A further arcuate internal bore  34 , best seen in  FIG. 5 , connect operator bore portion  30  with outlet portion  26 . 
   Slidably, sealingly retained within main piston bore portion  28  is a main piston assembly including a piston  36  equipped with the customary piston ring  38  and an integral piston rod  40  extending from the outer end force thereof. The inner end force or back side of piston  36  is equipped with a circular, elastic, central seal member  42  adapted to sealingly engage with an annular main orifice  44  at the inner end of main piston bore portion  28 . The outer end of main piston bore portion  28  is sealingly closed via a threaded cap or cover  46 . A spring member  48 , piloted by piston rod  40 , is interposed between cover  46  and piston  36 , for biasing piston  36  against annular main orifice  44 . Piston  36  also includes an axial equalizer hole or orifice  50  that permits pressurized fluid flow from inlet portion  24  to the backside of piston  36  and flow from there to a pilot orifice  52  in operator bore portion  30  via internal bore  32 . 
   The operator bore portion  30  of valve body  22  serves to threadingly receive a corresponding-threaded annular attaching portion  58  of an attachment nut  56  that serves to attach a known solenoid actuation assembly  54  of the normally-closed (NC) type. Solenoid assembly  54  includes a movable plunger assembly including a magnetic-material plunger member  62  having a circular elastic seal member  64  on its axial outer end portion, together with a biasing spring  68 , all of which are sheathed in a sleeve assembly  70  which in turn is surrounded by an electrically arcuatable coil  72  within an enclosure  74 . The operation of a solenoid mechanism is of course well known in the art. In the NC type solenoid utilized here, plunger member  62 , with its seal member  64  is normally biased against and seals pilot orifice  52 . Upon remote electrical operation, plunger member  62  is lifted off or separated from pilot orifice  52  by magnetic force, thus permitting fluid pressure communication from behind main piston  36  and outlet portion  26 , during the movement of main piston  36  from a valve-closed position to a valve-open position. The operation of the above-described valve structure, in conjunction with the previously recited method of operation of such remote pilot-operated valves is deemed to be well-known and understood to those skilled in this art. 
   As best seen in the exploded view in  FIG. 6 , remote pilot-operated valve  20  is basically comprised of valve body assembly  22 , main piston assembly  35 , and solenoid actuation assembly  54 , together with the novel manual override assembly  80  of this invention which will now be described in detail. 
   As best seen in  FIGS. 1 ,  2 ,  4  and  6 , manual override assembly  80  is sealingly rotatably retained in a stepped override assembly bore  82 , in valve body  22  substantially perpendicular and tangential to main piston bore portion  28  as well as perpendicular and radial to operator bore portion  30 . The location of override assembly bore  82  is so chosen that an intermediate small peripheral portion thereof just barely intersects and interrupts the outer peripheral wall portion  29  of main piston bore portion  28 , as best seen in  FIGS. 4 and 6 , in the form of a small arcuate window portion  84 , bounded on its lower axial extent at a flange portion  78  of the inner end of bore portion  28 , with flange portion  78  being in an adjacent parallel plane with the one wherein piston elastic seal member  42  bottoms out on axial orifice  50 . The upper axial extent of window  84  terminates within main piston bore peripheral wall portion  29  axially outwardly of inner flange portion  78 . The inner radial end of window portion  84  is substantially perpendicular to flange portion  78  while the outer radial end takes an arcuate shape that curves into the axial components of window portion  84 . 
   The axial inner end of override assembly bore  82  extends into and terminates partial within operator bore portion  30 , as best seen in  FIGS. 2 and 5 . Manual override assembly  80 , as best seen in  FIG. 6 , principally consists of a stepped, generally cylindrical override stem  90 , override stem retainer  112 , override cap  114  and a plurality of strategically placed sealing O-rings  116 , the latter serving to seal override stem  90  relative to its stepped bore  82 . 
   Turning now to  FIGS. 7-13 , these figures serve to disclose and define the shape and function of override stem  90 . As best seen in  FIGS. 7 and 11  stem  90  is generally cylindrical and is provided on the outer end, that extends from bore  82  ( FIG. 1 ) with a tool actuation portion  92  which may take any desired shape, such as a square drive as shown (for a wrench, etc.) or a slotted shape (for a screwdriver) or an aperture for inserting a handle, etc. The inner end of stem  90  takes the form of a cam that extends into operator bore portion  30 , (see  FIG. 5 ) and includes a flat portion  94  that blends into an arcuate camming surface  96 , as best seen in FIG.  7 . Adjacent to the inner end of cam  93  are two spaced cylindrical portions  98  and  100  concentric with the longitudinal axis of stem  90 . Cylindrical portion  98 , which also extends into operator bore portion  38 , is separated from cylindrical portion  100  by a discontinuous peripheral groove portion  102  defined by the opposed annular walls of cylindrical portions  98 ,  100  and a radial joining bridge portion  104 , as best seen in  FIGS. 11 and 12 . The upper surface  104   a  of bridge portion  104  is parallel with cam flat surface  94 . As best seen in  FIGS. 2 and 5 , since a substantial axial extent of bridge portion  104  and thus groove portion  102  extend into operator bore portion  28 , the radial extent of cylindrical portion  100  is so dimensioned that a section of the inner peripheral surface of threaded portion  58  of solenoid actuating assembly attachment nut  56 , upon the assembly of solenoid actuation assembly  54 , extends into discontinuous groove portion  106 , thus limiting the axial movement of override stem  90  and rotatably retaining same in override assembly bore  82 . At the same time, bridge portion  104 , by virtue of its partial extent into operator bore groove  102 , prohibits the rotation of override stem  90  by bottoming out in one direction of rotation against noted threaded portion  56  of solenoid assembly attachment nut  56  and bottoming out in the other direction of rotation after about 180 degrees of rotation or about one-half turn of stem  90 . 
   Cylindrical portion  100  is separated from adjacent cylindrical portion  106  by a coaxial bridge portion  108  thus defining a continuous peripheral groove portion  140  that serves to retain a sealing O-ring  196  (FIG.  2 ). The other side of cylindrical portion  106  is joined to an annular continuous peripheral groove portion  120  via an eccentric bridge portion  122  having a cylindrical portion  124  forming one edge of groove portion  120 . Eccentric bridge portion  122  is provided with a transverse flat area or surface  126  where lateral ends or edges  132  merge into a semicylindrical surface portion  128 . 
   As best seen in  FIGS. 7 ,  8  and  12 , the angulation of area or surface  126 , and thus of lateral edge  132  may be slightly rotationable offset, at a range of about 40 to 60 degrees clockwise, relative to the transverse centerline of override stem  90 , as seen in  FIG. 8 , and thus may be similarly offset relative to flat surface  94  of cam  93 . Preferably, this offset range is about 45 to 55 degrees and optimally at 50 to 55 degrees. This optional offset is not mandatory but does offer a bit of additional dwell or overlap between the actuation of cam surface  96  and the subsequent actuation of lateral edge  132 , as will be discussed in more detail hereinafter. 
   Defined between spaced cylindrical portion  124 ,  136  and  140  are annular cylindrical grooves  138  and  142 , respectively, that serve to retain further sealing O-rings  96  ( FIGS. 2 ,  6 ). As best seen in  FIG. 2 , an override stem retainer  112  is preferably threaded into stepped bore  82  for further axially retaining override stem  90  in bore  82  when solenoid actuation assembly  54  is removed from valve body  22 . In addition, an override cap  114  is also threaded into stepped bore  82  and is removed only if and when there is a reason to manually activate override assembly  80 . 
   As best seen in  FIG. 2 , when override assembly  80  is installed in its bore  82 , such that cam flat surface  94  is parallel with the bottom wall surface  63  of plunger member  62 , override stem bridge portion upper surface  104   a  (FIG.  12 ), when override stem  80  is turned in the counter-clockwise direction, will after a slight rotation engage the bottom annular surface of solenoid attachment nut threaded portion  56  and thus be stopped from further rotation. If override stem  90  is turned clockwise, camming surface  96  will, after a slight rotation, engage plunger member bottom surface  63  and axially displace same away from engagement with pilot orifice  52 , with maximum displacement occurring after an about 90 degree displacement, or an about one-quarter turn, of override stem  90 . This, of course, permits pressurized fluid transfer from behind main piston  36  to outlet portion  26 , via pilot orifice  52 . 
   This just noted displacement has also caused the rotation of one of the lateral flat edges  132  of stem eccentric bridge portion  122  to laterally enter the main piston bore peripheral wall portion  29  at inner flange portion  78 , and there starts to make physical contact with the innermost peripheral outer edge surface of piston  36  as best seen in FIG.  2 . Further clockwise rotation will cause flat edge  132  to engage the noted piston surface and axially displace same away from engagement with annular main orifice  44 , with maximum displacement occurring after an about further 90 degree displacement, or an about further one-quarter turn, of override stem  90 . This of course permits pressurized fluid transfer from inlet portion  24  to outlet portion  26 , via annular main orifice  44 . 
   Thus, the rotation or turning of the one override valve stem  90  with but a one-half turn causes same to lift solenoid operator plunger member or armature  62  during the first one-quarter turn and then to lift main piston  36  during the second one-quarter turn. When valve  20  is under pressure, pilot orifice  52  is opened, and main piston  36  shifts, via pressurized fluid opening away from main orifice  44  of valve  22 . By continuing to turn manual override stem  90 , main piston  36  is blocked open upon the reduction of pressure, which provides a noticeable time saving advantage in, for example, charging refrigeration systems. 
   If valve  20  is not under or subject to fluid pressure, manual override stem  90  sequentially first lifts solenoid plunger member  62  and then lifts main valve piston  36  in one easy about one-half turn. This combined sequential action is much more efficient than existing manual override mechanisms that merely thread up a plunger from underneath the main piston bore and force the piston off its orifice seat, requiring a high force load. The flattened lever action, via the flat lateral edge  132  of the intermediate portion of override stem  90  enters main piston bore portion  28  through the arcuate or curved window portion  84 . As a result of the rotation of override stem  90 , the flat lateral edge rotates in and out of piston bore portion  82 , thus either blocking or lifting main piston  36 , depending upon whether fluid pressure is acting on main piston  36 . 
   While there is shown and described a present preferred embodiment of this invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims.