Patent GB-823941-A (GB)
Title: Improvements in or relating to fluid controlling valves
Inventor: KNOX GRANVILLE SLOAN
IPC: F16K5/20
Filed: 1956-01-10
Abstract: 823,941. Valves. HYDRIL CORPORATION OF CALIFORNIA. Jan. 10, 1956, No. 891/56. Class 135. In a valve the final seal between the closure member and the opposing seat is accomplished by pressurising a coherent body of plastic material. In the first example, Fig. 2, the valve is of the plug type and comprises a housing 10b formed by sections 11b, 12b bolted together to form opposed passageways 16, 17. The plug 18a has a central passageway 19. The passageway 16 has a substantially spherical seating face 20 complementary to the adjacent face of the plug 18a. A sleeve 25 locates a ring 23 in the bore 22 of the body section 12b. An annular plastic ring 30 is located in a complementaryshaped channel 27 in the ring 23 but is normally set back from the mouth 28 of the channel. The rings 23, 30 have spherical faces 27a, 30b, respectively adjacent the plug 18a. A segmental pressure block 33 is located in a slot 32 at the top of the ring 23 below a threaded plunger 34 located in the body section 12b by a cap 37b and having a hand wheel 41. The plug 18a is provided with sockets 55, 56 in which roller bearing assemblies 57, 58, respectively, are press-fitted. The plug 18a is vertically centred by bearing rollers 59, Fig. 1. Stationary stud shafts 61, 66, Fig.. 2, extend into the bearing assemblies 58, 57, respectively. The valve stem 45b extends through the stud shaft 66 and at its lower end 71 extends into a key-way in the plug 18a. A gear segment 73, Figs. 2 and 3, is keyed to the top of the stem 45b and meshes with a pinion 84 mounted on the operating shaft 90 above the plunger 34. The gear 73 carries a pointer 82, Fig. 3, which indicates the position of the valve. The hub 83, Fig. 6, of the pinion 84 extends into a bore 86 in the cap 37b. The head 92 of the operating shaft 90 normally exerts no downward pressure on the plunger 34. The pinion 84 is initially, i.e. when the valve is open, rotationally coupled to the shaft 90 by a detent mechanism comprising, Fig. 5, an arcuate way 96 cut in the head 92 and a ball 100 located in a slot 95 in the hub 83 and held between the shoulder 101, Fig. 6, of the hub and the body section 12b. In operation, the hand wheel 41 is rotated clockwise, Fig. 3, causing, through the above detent mechanism, clockwise rotation of the pinion 84 which rotates the gear segment 73 and the valve stem 45b counterclockwise to bring the plug 18a to the closed position, the segment 73 being then arrested by a stop-pin 78. The slot 95, Fig. 5, in the hub 83 is then aligned with a notch 87 in the cap 37b so that on continued rotation of the sahft 90 the ball 100 is cammed into the notch 87 so locking the pinion 84 to the cap 37b. Upon continued rotation, the shaft 90 is screwed downwardly and the head 92 depresses the plunger 34 and the block 33, Fig. 2, to pressurize the backing-ring 30 and extrude it into sealing engagement with the plug 18a. To re-open the valve the hand wheel 41 is rotated counterclockwise to screw the shaft 90 upwardly so releasing the pressure on the plastic material 30 which resumes its initial form and so unseals the valve. When the shaft 90 has moved up sufficiently for the ball 100, Fig. 5, to again move radially inwards the pinion 84 is unlocked from the cap 37b so that continued rotation of the shaft 90 is imparted to the pinion 84 and the segment 73, Fig. 3, is rotated to bring back the plug 18a to its initial position, the segment 73 being arrested by a second stop-pin 77. In a modification, Fig. 15, the hub 83c of the pinion 84 is provided with saw-teeth 106 which co-operate with saw-teeth 108 in the head 92c of the shaft 90. The sloping faces of the teeth are spaced apart in the valve open position and the head 92c imparts rotary movement to the hub 83c through the vertical faces of the teeth. In an example in which the invention is applied to a gate valve, Fig. 17, the valve comprises a body formed by a main part 111, a cover part 112 bolted thereto, a bonnet 113 and a bonnet cap 114. The cover 112 and the wall 121 of the body 111 have aligned passages 127, 128 opening into the valve chamber 120 through the ports 130, 131 respectively. The valve chamber is connected by a by-pass 129 to the passage 128. The plug 126 has an annular groove 136 opening out to a mouth 138 at the top surface of the plug. The groove 136 is filled with a deformable plastic sealing body 140 moulded within the groove or bonded to the plug. Normally the material 140 is below the upper surface of the plug. The plug 126 is threaded to a sleeve 158 the outer enlarged end 164 of which slides in the bore 166 of the bonnet 113. Within the sleeve 158 is a plunger 141 which has an extension 143 of rectangular cross-section which extends through the member 140 and into the plug 126. The end of the extension 143 and the shoulder 148 of the plunger 141 lie adjacent the material 140. On the plunger 141 is a collar 154 located in a bore 167 of the sleeve 158. Four cylindrical rollers 169 are located in sockets in the end 164 of the sleeve 158 just in advance of the collar 154. A tubular nut 186 is screwed to the head 164. The hub 181 of a hand wheel 182 is screwed on to the plunger 141. In operation the wheel 181 is rotated righthandedly to move the plunger 141 to the left and through the collar 154 and the rollers 169 the sleeve 158 and the plug 126 are moved to the left until the shoulder 165 of the sleeve 158 engages a stop-ring 162 in which position the mouth 138 of the groove 136 fully encircles the port 130. The detent rollers 169 are then inside the enlarged bore 173 of the bonnet 113 so that upon continued inward movement of the plunger the detents 169 are moved outwardly by the collar 154 so that the plunger 141 moves to the left to cause the material 140 to be extruded from the mouth 138 and engage the inner surface 122 of the cover 112 and form a tight seal, Fig. 22. As the plug 126 moves to the left its leading edge L pushes foreign matter to the end of the chamber 120 and excess fluid is discharged through the by-pass 129. To open the valve the hand wheel 182, Fig. 17, is rotated in the reverse direction to withdraw the plunger 141 to the right to allow the material 140 to resume its initial form. When, on continued rotation of the hand wheel, the collar 154 engages the nut 186 the plug 126 is moved to the right. In operation of the valve, the material 140 at the mouth 138 of the groove 136 is never exposed to differential pressure conditions which could cause extrusion of the material. In a modification, Fig. 23, the valve is similar to that of Fig. 17, but the sealing medium 140a is located in an arcuate cavity 136a in the plug 126a and a body 207 of similar sealing material is located in a groove 203 in the face 122 of the cover 112. The cavity 136a has a mouth 138a and the groove 203 has a mouth 209. The operation is as in the Fig. 17 embodiment. When the member 126a is in its closing position the two mouths 138a, 209 overlap so that the pressure exerted on the material 140a by the plunger is transmitted to the material 207 and both materials 140a, 207 are extruded from their associated mouths 138a, 209 to effect sealing. Again at no time in the operation of the valve are the materials 140a, 207 subject to differential fluid pressure. In the last example as applied to a rotating plug valve, Fig. 30, the valve body comprises a body 110c and a cap ring 112c bolted thereto. Within the valve chamber 120c is a rotary cylindrical plug 126c which has upper and lower necks 235, 236 which bear in rings 237, 238, respectively. The plug 126c has a passageway 239 which in the valve open position communicates with passages 127c, 128c, having orifices 130c, 131c. Plug 126c has a cavity 136c, Fig. 36, having an annular mouth 244 which in the valve closed position encircles the orifice 130c. Within the cavity 136c is the sealing medium 140c which may be moulded in place or bonded to the cavity walls. Located in the bore 248, Fig. 30, of the plug neck 235 is a pressure block 215c below a plunger 253 operated by a hand wheel 182. When the valve is in the open position rotation of the plunger 253 is frictionally transmitted to the plug of three roller detents 269, 270, 271, Fig. 32, until the plug is arrested by a fixed pin. The annular mouth 244, Fig. 36, then encircles the port 130c. Upon continued rotation of the hand wheel 182 the collar 254 pushes the detent rollers outwardly into notches 264, 265, 266, Fig. 32, in a locking-ring 250, so that the stem 253 moves downwardly to depress the block 215c, Fig. 36, and pressurize the sealing medium 140c which extrudes from the mouth 244 to form a tight seal. Upon reverse rotation of the hand wheel 182 the plunger 253 is withdrawn before the plug is rotated to valve-open position. The sealing medium is never exposed to differential fluid pressure tending to cause extrusion from the mouth 244.