Low-noise rotary control valve

0001<b>THIS INVENTION</b> relates generally to rotary control valves such as ball valves or cylindrical plug valves. More particularly, the invention relates to such valves which are modified to reduce noise and vibration produced during partial closure of such valves.

0002The voluminous prior art of rotary control valves has searched for solutions to the problem of noise generation during throttling operation of such valves. US-A-5,070,909 tries to solve the problem by placing parallel conduits in entry and exit flow passages of the valve body and also placing similar conduits in the flow path of the ball valve in the valve body. Additionally, transverse holes between channels are provided in the ball valve.

0003US-A-4,774,984 discloses a cylindrical plug valve with the plug having a flow passage through it dividing the plug into two halves. One half serves to close the flow passage of the valve when it is in a fully closed position. The other half has channels provided in it, such that when the valve is in a throttling position, fluid is partially directed through the channels in the plug element. Such channels are provided in the plug in an effort to decrease flashing and cavitation of the fluid through the valve so as to reduce noise.

0004US-A-4,530,375 discloses an attenuating rotating valve in which the rotating closure member or valve element may be rotated from a fully closed position to a throttling position to a fully open position.

0005US-A-4,364,415 discloses still another throttling ball valve in which the interior of the flow passage of the ball valve element includes longitudinal baffles which require fluid passing through the valve when it is in a throttling position to traverse a tortious back and forth longitudinal path to the valve exit passage.

0006All of the valves identified in the above description of prior art are characterised by high cost in fabricating attenuation devices within the valve.

0007US-A-223,573, which forms a basis for the preamble of claim 1 and claim 3 discloses a valve assembly including a valve body which defines respective entry and exit flow passages which together define a longitudinal axis. A valve member, having a passage which extends through the valve member, is rotatably mounted in the valve body for rotation about a predetermined axis between an open position and a closed position. A diverter is provided in the entry flow passage of the valve body at a position adjacent the valve member to divert flow entering the valve member. A co-operating diverter is mounted on an edge of the valve member which faces the entry flow passage. The two diverters co-operate increasingly to restrict the flow through the valve as the valve is moved towards the closed position.

0008A primary object of this invention is to provide an improved rotary control valve that is characterised by simplicity and low cost, yet is effective in reducing noise during throttling operation of the valve.

0009According to one aspect of this invention there is provided a valve assembly including a valve body having entry and exit flow passage formed therethrough, said entry and exit flow passages defining a longitudinal axis; a valve member having a passage extending therethrough, said passage dividing said valve member into an upper portion and a lower portion, means for mounting said valve member in said valve body for rotation about a lateral axis with respect to said valve body between a completely open position and a completely closed position; sealing means providing in said valve body flow passage for operatively engaging said valve member for preventing fluid flow through said flow passage of said valve member once said valve member is in said closed position; an entry flow passage diverter disposed in said entry flow passage of said valve body at a position adjacent said valve member extending upwardly from said valve body into said entry flow passage; an entry valve member diverter disposed on an edge of said valve member, which faces said entry flow passage, said entry valve member diverter extending downwardly from an upper portion of said passage through said valve member when said valve member is in a fully open position with respect to said valve body; said flow passage diverter and entry valve member diverter being co-operatively arranged and sized in relation to said valve member passage through said valve member to present limited impedance to fluid flow from said entry flow passage of said valve body when said valve member is rotated to a completely open position with respect to said valve body, wherein said flow passage diverter and said entry valve member diverter co-operate to increasingly restrict flow from said entry flow passage to said valve member passage as said valve member is increasingly rotated from said open position toward said closed position wherein said flow passage diverter includes a plurality of teeth extending upwardly from said flow passage of said valve body, and wherein said entry valve member diverter includes a plurality of teeth extending downwardly from said upper portion of said valve member.

0010Preferably wherein said teeth of said entry flow passage diverter are aligned vertically with said teeth of said valve member diverter, but said teeth are separated by a small longitudinal distance along said valve body such that said teeth of said entry valve member diverter rotate past said teeth of said entry flow passage.

0011According to another aspect of this invention there is provided a valve assembly including a valve body having entry and exit flow passage formed therethrough, said entry and exit flow passages defining a longitudinal axis; a valve member having a passage extending therethrough, said passage dividing said valve member into an upper portion and a lower portion, means for mounting said valve member in said valve body for rotation about a lateral axis with respect to said valve body between a completely open position and a completely closed position; sealing means providing in said valve body flow passage for operatively engaging said valve member for preventing fluid flow through said flow passage of said valve member once said valve member is in said closed position; an entry flow passage diverter disposed in said entry flow passage of said valve body at a position adjacent said valve member extending upwardly from said valve body into said entry flow passage; an entry valve member diverter disposed on an edge of said valve member, which faces said entry flow passage, said entry valve member diverter extending downwardly from an upper portion of said passage through said valve member when said valve member is in a fully open position with respect to said valve body; said flow passage diverter and entry valve member diverter being co-operatively arranged and sized in relation to said valve member passage through said valve member to present limited impedance to fluid flow from said entry flow passage of said valve body when said valve member is rotated to a completely open position with respect to said valve body, wherein said flow passage diverter and said entry valve member diverter co-operate to increasingly restrict flow from said entry flow passage to said valve member passage as said valve member is increasingly rotated from said open position toward said closed position wherein said flow passage diverter includes a plurality of passages which are substantially parallel with said valve body longitudinal axis, and said entry valve member diverter includes a plurality of passages which are substantially parallel with said valve member longitudinal axis.

0012Preferably the valve assembly further comprises an exit valve member diverter disposed on an edge of said valve member which faces said exit flow passage, said exit valve member diverter extending upwardly into said exit flow passage.

0013Advantageously the valve further comprises a plurality of transverse passages through said lower portion of said valve member, whereby a portion of fluid within said valve member passage may be channelled through said lower portion in alternative paths to said exit flow passage from said valve member passage.

0014The objects, advantages and features of the invention will become more apparent by reference to the drawings which are appended hereto and wherein like numerals indicate like parts and wherein an illustrative embodiment of the invention is shown, by way of example, of which: <ul id="ul0001" list-style="none"><li>FIGURE 1 presents a side view of the ball valve with the valve body shown in section in the longitudinal direction of the flow passage,</li><li>FIGURE 2 is a section through the valve of Figure 1 at the middle of the flow passage as viewed in the direction of the valve actuating stern, where the valve is in a throttling or partially closed position,</li><li>FIGURE 3 is a section through the valve similar to that of Figure 2 but showing the valve in a fully open position,</li><li>FIGURE 4 is a view looking into the valve along lines 4-4 of Figure 3 which illustrates a preferred embodiment of the impediments or flow diverters at the entry into the flow passage of the ball element of the valve,</li><li>FIGURE 5 is a view looking into the valve along lines 5-5 of Figure 2 which illustrates the relative positions of the flow diverters with the ball element of the valve partially closed, and</li><li>FIGURE 6 is a view similar to that of Figure 4 but shows an alternative construction of the impediments or flow diverters.</li></ul>

0015Figure 1 of the drawings shows the reduced noise throttling valve of the invention. A side view of a ball (closure member) 12 shows that it is installed in a side port or a side entry 11 of valve body 10.

0016Such ball valve 12 is installed within valve body 10 where the entry sleeve 70, entry spring 72 and entry plug 74 and exit sleeve 70', exit spring 72' and exit plug 74' are removed from valve body 10. Ball valve 12 includes an actuating stern 22 comprising an outer portion 22' and an inner portion 22'. The valve body 10 includes a recess 17 into which a sleeve 19 is fixed. On insertion of the ball valve 12 and actuating stem 22 into side entry 11, the inner portion of the actuating stem 22" is inserted into sleeve 19.

0017On the other side of the ball valve 12, a side entry plug 21 is provided which is fastened to valve body 10 for example by bolts 23 into threaded holes of the valve body 10. A gland packing 18 and gland 20 enable the outer portion 22' of actuating stem 22 to turn with respect to side entry plug 21 yet prevent pressurized fluid from escaping to the exterior of the valve. The inner portion 22" of actuating stem 22 rotates within sleeve 19. "O" ring 25 seals the side entry plug 21 with respect to valve body 10.

0018After the ball valve has been installed via side entry 11, entry retaining pin 78 and exit retaining pin 78' are installed in valve body 10. Next, entry sleeve 70 is inserted via entry port 73 until it is stopped by entry retaining pin 78. Exit sleeve 70' is inserted via exit port 73' until it is stopped by exit retaining pin 78'.

0019Spring 72 is placed between a shoulder of entry sleeve 70 and an entry plug 74 which may be fastened within entry port 73 by threading or the like. Likewise, spring 72' is placed between a shoulder of exit sleeve 70' and exit plug 74' by threading or the like. Springs 72 and 72' force sleeves 70 and 70' into proper position adjacent the exterior of ball valve 12. "O" ring seals 26 on the entry side and 26' on the exit side are placed in recesses 24 and 24'. Such "O" rings seal the ball valve 12 to the entry and exit sleeves so as to prevent fluid pressure from escaping from entry flow passage 15 to exit flow passage 16. "O" ring seals 76 and 76' seal the entry sleeve 70 and the exit sleeve 70' from the space between the ball valve 12 and the valve body 10.

0020As mentioned above, an entry flow passage is defined within the interior of entry plug 74 and entry sleeve 70. An exit flow passage is defined within the interior of exit plug 74' and exit sleeve 70'. Ball valve 12 includes a bore or passage 14 through which it may be axially aligned with the longitudinal axis 85 of the valve (See Figure 2).

0021Figure 2 best illustrates the impediments or flow diverters 28, 30 and 32 of the throttling valve of this invention. Flow diverter 28 rises upwardly from entry sleeve 70 or from valve body 10 into entry flow passage 15. Such diverter 28 includes teeth 29 as illustrated in Figure 4 or may alternatively include longitudinal passages 90 as illustrated in Figure 6. Extending downwardly from the leading or forward edge of the upper portion 50 of ball element 12 is another flow diverter or impediment 30. Preferably such diverter 30 includes teeth as illustrated in Figures 4 and 5, but alternatively, as illustrated in Figure 6, passages or holes 92 may be provided.

0022The illustrated condition of the throttling valve of Figure 2 is one of partial closure. In such condition the longitudinal axis 86 of the flow passage 14 of ball 12 forms an angle with the longitudinal axis 85 of inlet 15 and outlet 16 flow passages and valve body 10. Pressurized fluid passes by and through flow diverters 28 and 30 on its way to exit flow passage 16. Such impediments inhibit vortex formation and break flow into smaller streams within ball flow passage 14 thereby reducing vibration and noise as well as reducing cavitation. Diverter 32 extends upwardly from lower portion 52 of ball 12 into outlet passage 16 so as to inhibit vortex formation downstream of outlet passage 16 and thereby reduce cavitation and noise generation at the outlet of the valve.

0023As an additional means for vortex prevention within flow passage 14 of ball 12, a plurality of transverse passages 40 are provided in lower portion 52 of ball valve element 12. With increasing rotation of ball valve element 12, more passages 40 are open to outlet passage 16 thereby providing alternative paths for pressurized fluid within passage 14 to reach the outlet 16. Such alternative paths further inhibit vortex creation in passage 14 and serve to reduce valve noise when a compressible fluid, such as gas, is being throttled through the valve.

0024Figure 3 illustrates the valve of the invention in a fully open condition. The flow diverters 30, 28 and 32 restrict flow only a small amount in such fully open condition. Figure 4 illustrates the opening into the passage 14 via inlet passage 15. Teeth 29 and 31 are spread a substantial distance apart, such that the teeth provide only small impedance to flow when the valve is in the fully open position. Preferably, the teeth 31 of flow diverter 30 are aligned with the teeth 29 of flow diverter 28. Flow diverter 28 is fixed and separated a small longitudinal distance from diverter 30. As a result, as the valve member 12 is rotated to a throttling condition as illustrated in Figures 2 and 5, the teeth 31 of diverter 30 close toward the teeth 29 of diverter 28. The teeth of diverter 30 rotate past the teeth of diverter 28 until at closure, the outer surface of top portion of valve member 12 closes the flow passage 15.

0025The diverter 32 of the lower portion 52 of ball 12 which extend upwardly into the outlet flow passage preferably includes upwardly facing teeth similar to teeth 29 of inlet diverter 28.

0026As mentioned above, Figure 6 illustrates an alternative embodiment of a diverter 28' having holes or passages 90 through it with a closure member diverter 30' having holes 92 through it.

0027Although it is preferred that valve member 12 be a ball, plug valve elements could be provided with proper rearrangement of valve body 10, and other valve parts. Such plug valve element could be of cylindrical shape.

0028While several embodiments of the present invention have been illustrated in detail, it is apparent that modifications and adaptations of the embodiments shown will occur to those skilled in the art. For example, although a side entry is provided for the ball 12 within valve body 10, other valve structures may be substituted for the side entry design. Such other structures are well known in the ball valve design art. However, it is to be expressly understood that such modifications and adaptations are within the scope of the present invention as set forth in the following claims.