Fluid pressure reduction device

The present invention relates to a device that dissipates fluid energy, particularly a device that depressurizes a fluid, and reduces the conversion of energy into noise for gas flow and suppresses the occurrence of cavitation (cavitation phenomenon) for liquid flow. It relates to a fluid decompression device with less energy.

Some factors related to the present invention will be considered item by item. In particular, the pressure reducing device of the present invention will be described below separately for (A) aerodynamic noise, (B) fabrication, and (C) hydrodynamic noise.

(A) Aerodynamic noise When controlling a fluid in an industrial process such as an oil or gas piping line or a chemical reaction facility, it is often necessary to reduce the pressure of the fluid. Flow control devices such as flow control valves and flow controllers that can control the flow rate, and back pressure devices such as diffusers and silencers are used for this purpose. The purpose of the flow control valve and / or the flow control device in some applications is to regulate the flow rate and other process variables, but the pressure of the fluid decreases with the flow control.

Mechanical energy is built into the pressurized fluid. This energy is related to the decrease in pressure. This energy manifests itself as the kinetic energy of the fluid, including the motion of the entire fluid and local turbulence. Turbulence is a chaotic movement of fluid. However, there is order in the chaotic movement when viewed momentarily. Even if a turbulent flow (vortex) is formed, it is immediately divided into small vortices and disappears. Finally, the viscosity of the liquid eliminates the small vortices and converts the kinetic energy of the fluid into heat. Fluctuations in pressure and flow velocity caused by turbulence cause vibrations in the structural members of the piping system. Vibration is an undesired phenomenon that causes fatigue failure, wear, performance degradation, or damage to the mounting equipment of the pressure holding member (even if the member is strong). Even if there is no physical damage due to vibration, when the vibration propagates in the air, it makes an unpleasant noise to the ear.

Three basic noise prevention methods: 1) Suppression of vibration at the place of occurrence. The amount of energy dissipated depends on the application, but the noise reduction level is based on the reduction in the conversion rate of fluid energy to sound energy.

2) Absorption of noise energy. A typical example of industrial equipment is a glass fiber-filled silencer.

3) Blocking noise propagation. An example of this is a thick pipe. Part of the total energy converted to vibration is related to the nature of the flow path and the turbulence of the fluid, and further to the energy absorption characteristics of the structural members in contact with the fluid. The amount of mechanical energy converted to noise energy is known as acoustic conversion efficiency. Several methods are known for reducing noise and vibration caused by depressurization of fluid.

When the fluid is a gas, the following four methods are used.

1) In processes where turbulence is likely to occur, depressurize in multiple small steps instead of decompressing at once. As the pressure reduction step, contraction or expansion of the flow path or change of direction of the flow is usually used. In either case, a jet of high speed fluid is formed within the low speed region of the fluid. Noise is generated by the turbulent mixing of the fluid generated at this time. If the pressure change before and after this decompression step is large, the jet will block the flow, or the flow velocity of the jet will reach the speed of sound and an "impact" will occur inside the fluid. This impact causes the thermodynamic state of the flow to change abruptly. For example, the pressure drops significantly. When an impact is applied to the inflowing turbulence, noise in a wide frequency range is generated.

2) Prevent high-speed jets and turbulent streams from coming into contact with solid surfaces. Disturbances in free flow, so-called Reynolds stress, cause noise. However, contact with the solid surface causes resonance. Resonance can be a powerful source of noise even when the average flow velocity of the fluid is low.

3) First, divide the flow into smaller flows. This technique yields many favorable results. As the size of the flow path becomes smaller, the size of the generated vortex also becomes smaller, so that the frequency of the vortex becomes higher. Then, the energy shifts to the process of extinguishing the vortex without changing to vibration. Second, most of the energy contained in small vortices is high frequency energy that is difficult to absorb (easily dissipate as noise) in piping systems. Therefore, in an actual piping system, dividing the flow into smaller flows is effective in suppressing the propagation of generated noise. Thirdly, high-frequency noise is difficult for the human ear to hear, so this also provides an apparent noise prevention effect. Fourth, it is relatively easy to prevent resonance due to collision of a small jet with a solid surface. Finally, as long as each jet is independent in the split stream, it has nothing to do with the noise generated by the other streams, so the overall noise can be kept low, similar to the stepwise decompression. However, there is a limit to the miniaturization of the flow because the flow path is blocked by foreign matter in the fluid.

4) A combination of the above measures. One problem with stepwise decompression of a compressible fluid is that decompression increases the volume of fluid flowing to the next step. When the pressure ratio (inlet pressure / outlet pressure) in the depressurization stage is high, it is necessary to increase the flow path cross-sectional area with the increase in the volume of the fluid downstream of the pressure ratio. Many conventional flow control devices use an expanding flow path. These flow restraints for compressible fluids are used by an annular cage wall through which the fluid flows radially outward. This is preferable in that the flow path naturally expands to obtain a wide flow path cross-sectional area. The technical problem for suppressing the noise and vibration generated by the depressurization of the fluid is to obtain a flow path shape that can efficiently control the flow state and can be manufactured at low cost.

(B) Manufacturing problems Providing a suitable flow path inside the noise suppression member is usually costly. Constructing the flow path with a special material is also problematic in terms of cost and availability. An annular casting or rod can be used as a flow restraint member in a cylindrical flow path such as a widely used sleeve or ring. However, it must be manufactured by combining many factors such as the diameter, length, and thickness of the material. A valve cage in which cyclic discs of various inner and outer diameters cut out from ordinary plate materials are laminated at a certain height is used. The sheet-shaped forged product is advantageous over the annular casting in that voids are less likely to be formed.

Laminated discs have been manufactured by chemical etching, milling, electrical discharge machining (EDM), casting, cutting, punching, drilling and the like. Chemical etching is a widely used processing technique, but it is very expensive in terms of dimensions for processing valve cage parts. Furthermore, in this processing method, acidic waste liquid and dissolved metal become hazardous waste. Milling is expensive and the dimensions of the cutter constrain the minimum dimensions of the workpiece. Wire electric discharge machining is limited to through machining, and machining takes time. Plunge EDM is used to machine recesses and is suitable for mold making, but not for mass production of discs. Casting is inexpensive, but a mold is required for each type of product. In addition, the cast product needs to be finished before laminating. Punching is limited to punching and requires a dedicated die according to the shape of the punched object, and the punched product is not always flat. The shape of the flow path changes due to the wear of the die, which adversely affects the flow control characteristics. Further, it is not particularly suitable for manufacturing a disc having a large thickness and a small size. Drilling is not suitable for machining asymmetric channels and tapered holes. In addition, it is not possible to round the corners inside the annular car by drilling.

Cutting methods include plasma processing, laser processing, high-pressure water jets, and the like. These are limited to penetration processing. However, the flow rate suppressing member cannot be manufactured at low cost by the conventional penetration processing. For example, the skeletal disk described in US Pat. No. 3,513,864, granted to Self, requires frequent injection and stopping of frames / beam jets at each machining location. Since this frequent injection / stop and movement of the workpiece are required, the machining time and machining cost per machining length increase. Therefore, there is a demand for a disk shape that can be processed efficiently and inexpensively.

In addition, the widespread use of computer numerically controlled (CNC) machine tools, CAD systems, and automated interfaces is shifting to software-based CNC machining, which is more cost effective than mold manufacturing (casting). .. This software is advantageous for special applications where noise protection is required and, in some cases, special shapes are required.

The stack of discs is usually assembled by brazing and bolting. The discs can also be assembled by welding them together.

In addition to the cost of the flow control member, the size of the flow control member required for a given flow rate is related to the size of the valve, which affects the cost of the entire valve.

The conventional bending flow path is an inefficient flow path for uniformly reducing the pressure. The flow rate passing through a predetermined flow path cross section is smaller than that of, for example, a two-stage decompression device. Therefore, the flow rate suppressing member based on the conventional bending flow path has a large size because the flow path cross-sectional area and the number of steps per flow path are large. The large size of the flow control member requires a large, heavy and expensive valve for accommodating the flow control member, and the actuator for operating the valve is also large.

(C) Fluid dynamic noise The mechanism of generating dynamic noise associated with the decompression of a liquid is different. The fabrication technique according to the present invention is also advantageous for liquid flow paths. In practical applications, cavitation is the main cause of noise and vibration caused by the decompression of liquids. Cavitation occurs when the liquid passes through a region where the pressure in the flow path is below the vapor pressure. When the liquid that generated the bubbles flows to the region where the pressure becomes higher than the vapor pressure, the bubbles disappear. Noise and vibration are generated as the bubbles disappear, damaging the material.

One of the solutions to this problem is to keep the pressure in the flow path above the vapor pressure. Multiple decompression steps are often used in the gas flow. The required number of stages of decompression is related to the total pressure drop amount, that is, the minimum pressure drop amount at each stage with respect to the pressure recovery amount. It is desirable that the amount of pressure recovered is small. Laminated flow control members often use a decompression step that converts the flow in the perpendicular direction, and pressure recovery is performed at the flow conversion point. Therefore, more flow conversion points are required for the depressurization step, but as the number of depressurization steps increases, the complexity of the flow suppressor increases, and the size and cost of the entire valve increase.

In practice, it is advantageous to increase the amount of decompression in the first stage (the stage where the static pressure is maximized) and gradually decrease the amount of decompression in each subsequent stage. A flow path having each decompression step by changing the direction of the flow is also called a cross-section expansion flow path.

For compressible flow, smaller flow path dimensions are advantageous. Conditions that result in small amounts of cavitation are often acceptable. A large number of independent small two-phase jets (local high-speed streams of a mixture of gas and liquid) have lower vibration generation efficiency than large two-phase jets.

The flow rate control of the liquid is, in principle, an indirect means of controlling the vibration and noise of the liquid.

The purpose of flow velocity control is to reduce Bernoulli's effect of locally reducing static pressure in the overall flow of the liquid. This relatively high static pressure narrows the pressure range that causes cavitation.

<p> It is an object of the present invention to provide a fluid decompression device which can be converted into noise energy, that is, can suppress the generation of hydrodynamic noise, and can be efficiently manufactured at a low cost.</p>

<p> In order to solve the above problems, the present invention is, in principle, a fluid decompression device having at least two stacked discs, each of which has a flow path for guiding a fluid from an inlet to an outlet. For compressible fluids, a first stage for high pressure recovery and a second stage for low pressure recovery are provided in series in the flow path. By arranging the first stage and the second stage in series in the disk stack, it is possible to reduce the pressure of a predetermined fluid while suppressing the generation of noise. Regarding the decompression of the liquid, it is desirable that all stages have a low recovery rate type.</p><p> In another embodiment of the fluid decompression device of the present invention,<u style="single">Each of the plurality of disks is (a) a fluid inlet step slot provided partially extending from the central cavity toward the outer periphery and provided on a half circumference, and (b) partially extending from the outer periphery toward the central cavity. It has a fluid outlet stage slot that extends and is on the same half-circumferential side as the fluid inlet stage slot, and (c) has at least one plenum in a partial annulus between the central cavity and the outer circumference, wherein the plenum is said to be said. A fluid is provided on the half-circumferential side different from the fluid inlet stage slot and the fluid outlet stage slot, and fluid flows from the fluid inlet stage slot of at least one disk of the plurality of disks to the plenum of an adjacent disk adjacent thereto, and then the said. The fluid inlet stage slot and the fluid outlet stage slot of the one disk are aligned with the plenum of the adjacent disk so that the fluid flows through at least one of the fluid outlet stage slots of the disk. Each is arranged and the flow of the fluid inlet stage slot is bisected and flows into the plenum of the adjacent disc to form a plurality of radial outward flows, at least one of the fluid outlet stages of the disc. It is configured to drain from the slot.</u></p><p> In another embodiment of the fluid decompression device of the present invention, a large number of partial laminates of two pairs of discs are laminated, the inlet and outlet slots are all provided on one disc, and the plenum is on the other. It is provided on the disk of. In this embodiment, unlike the other embodiments, the flow resistance cannot be changed smoothly according to the insertion and removal of the valve stem. A device using two types of discs is disadvantageous as compared with a device using one type of disc described above.</p><p> In another embodiment of the fluid decompression device of the present invention, there are seven decompression stages, and each stacked disc is (a) a fluid inlet slot extending partially from the center of the disc toward the outer periphery of the disc. It has (b) an exit stage slot extending partially from the outer periphery of the disc toward the center of the disc and (c) at least one plenum slot extending inside the disc. In this embodiment, each slot forms a plurality of contraction / expansion channels (compared to the embodiment) in the longitudinal direction of the stage. Further, as the fluid moves from one stage to the next, the discs are stacked in different orientations within the stack so that they pass through the slots and plenum of adjacent discs. In this embodiment having a large number of decompression steps, the number of overlapping slots in the laminate increases, resulting in undesired upstream and downstream. This is not particularly preferable when the liquid is depressurized, but upstream and downstream can be prevented by interposing a thin partition plate between the discs at a certain height in the laminated body. An embodiment having three to six stages (or seven or more stages) of decompression stages can be easily considered by those skilled in the art.</p><p> In a preferred embodiment of the present invention, a plurality of discs having an outer peripheral portion and a central hollow portion are laminated to form a slot group in which the discs complement each other. Thus, each disc is the same disc with a plurality of fluid inlet step slots partially extending from the center of the disc towards the outer circumference of the disc. The inlet corners of each fluid inlet slot are rounded to prevent flow separation, and the flow path is tapered to reduce noise generation and achieve high decompression. At the end of the tapered flow path, a rear slot of limited size is formed to communicate with the plenum of the vertically adjacent discs. These will be described later.</p><p> Each disc is further provided with an exit stage on the same side as the inlet stage in the circumferential direction on the outer circumference of the disc, and has a plurality of exit stage slots partially extending toward the center of the disc. Each outlet stage slot is a flow path that narrows toward the downstream in order to suppress the generation of noise as a low recovery stage on the downstream side. Further, each exit stage slot has a slot front portion that communicates with the plenum of the vertically adjacent discs.</p><p> Further, each disc has a slot-shaped plenum portion on the opposite side in the circumferential direction from the inlet and outlet stage slots.</p><p> In the laminated body, a partial laminated body composed of the above four discs is used. Stack the second disc in the opposite direction on top of the first disc so that the plenum portion of the second disc overlaps the inlet and exit stages of the first disc. The third disc has the same orientation as the first disc, but is turned over and stacked on the second disc. As a result, the plenum portion of the third disc overlaps the inlet and outlet stages of the second disc. Finally, flip the 4th disc in the same orientation as the 2nd disc, but stack it on the 3rd disc. Therefore, the inlet and outlet stages of the 4th disc overlap the plenum portion of the 3rd disc.</p><p> Further, each inlet stage slot and each exit stage slot of each disk are arranged asymmetrically. Due to this asymmetrical arrangement, the inlet and outlet stage slots of the discs adjacent to each other across the plenum of one disc do not overlap each other in the stacking body, so that the occurrence of unwanted upstream and downstream in the stacking body can be prevented. it can.</p><p> Therefore, in this preferred embodiment, the fluid that has flowed into the central cavity of the stacked discs will flow into the plurality of inlet slots formed as the high pressure recovery step. The fluid flowing into the inlet slot is divided into upper and lower parts from the rear slot portion and flows into the plenum portion of the adjacent disk. The divided fluid flows radially through each plenum portion and is dispersed in the circumferential direction, and is dispersed and discharged from each outlet slot formed as a low-pressure recovery step provided on the outer periphery of the vertically adjacent discs.</p><p> When applying this embodiment to a gas flow, it is desirable to operate at a pressure ratio of about 2 or more at the high pressure recovery stage in order to suppress noise generation. Furthermore, it is desirable to operate at a pressure ratio of about 2 or less at the low pressure recovery stage. As a result, the gas can be depressurized efficiently with less noise. The device of the embodiment described above is a device in which a fluid radiates outward in the disk stack. However, it will be obvious to those skilled in the art to reverse the inlet and outlet of the fluid so that the fluid flows inwardly through the laminate.</p>

<p> The fluid decompression device based on the principle of the present invention has the following structural and operational features and advantages.</p><p> 1) The generation of aerodynamic noise can be minimized due to the shape of the flow path that suppresses flow separation and impact.</p><p> 2) Regarding the flow of liquid, the occurrence of cavitation can be prevented by the flow path shape that can prevent the flow from peeling and recover the pressure.</p><p> 3) By forming a channel having a desired shape with ordinary materials, it is possible to reduce the inventory of products and shorten the delivery time.</p><p> 4) The shape of the flow path in the equipment can be manufactured efficiently and inexpensively by the latest processing equipment such as numerically controlled lasers or high-pressure water injection type machine tools.</p><p> 5) Since the size of the decompression member is smaller than that of the conventional bending flow path type currently used, the cost of the entire valve can be reduced.</p><p> 6) Since the flow path resistance of the decompression member changes smoothly according to the valve opening, the control characteristics of the valve are improved.</p><p> 7) A tightly assembled disc laminate can be manufactured at low cost and easily disassembled for repair or cleaning.</p><p> 8) It is possible to manufacture a fluid decompression member for special purposes at a low processing cost.</p><p> In the conventional decompression device, the fluid flows in the bending flow path in a zigzag direction in the radial direction, and the heights of the inlet and the outlet are not the same. In the decompression device of the present invention, the fluid flows three-dimensionally, but the inlet and outlet are at the same height.</p>

An embodiment of the present invention will be described with reference to the drawings.

First, FIG. 1 illustrates a fluid decompression device based on the principle of the present invention, which is a valve cage 10 type provided in a flow control valve 12 and equipped with a plurality of laminated disks. The flow control valve 12 includes a valve box 14 having a fluid inlet 16, a fluid outlet 18, and a flow path 20 between them. A seat ring 22 is provided in the valve box flow path 20, and cooperates with the valve operating member 24 to control the flow rate of the fluid flowing from the inside to the outside of the valve cage 10. The valve cage 10 is held in the valve by a known mounting means such as a cage holding device 26 and a mounting bolt 28 connected to the bonnet portion. The valve cage 10 is composed of a plurality of stacked discs, and each disc is the same disc 30 shown in FIG. Disk 30 has a central cavity 32<u style="single">Disc circumference</u>Has 34. Multiple fluid inlet stage slots 36 on one side of the disk 30<u style="single">Central cavity</u>A plurality of fluid outlet stage slots 38 extend partially from 32 toward the disc outer circumference 34, and a plurality of fluid outlet stage slots 38 partially extend from the disc outer circumference 34 toward the central cavity 32.

Disc circumference<u style="single">34</u>At the fluid inlet<u style="single">Stage slot 36</u>And fluid outlet stage slot<u style="single">38</u>On the opposite side of the circumferential direction, in one or more places<u style="single">Plenum</u>40 formed, fluid inlet<u style="single">Stage slot 36</u>And fluid inlet stage slot 36 and fluid outlet from one plenum end 42 near one end of fluid outlet stage slot 38<u style="single">stage</u>It extends across the disc to the other plenum end 44 near the other end of slot 38. The plenum 40 is also provided with a disc inner portion 41 along the central cavity 32 and a disc outer portion 43 along the disc outer circumference 34. The bridge portion 45 that connects the inner portion 41 and the outer portion 43 is<u style="single">Plenum</u>40 is divided into two plenum parts.

As shown in FIG. 2, each disc is provided with two holes 46 facing each other. A pair of alignment pins are inserted into the holes 46 penetrating each disc 30 when stacking the discs. As is clear from FIG. 2, the pins inserted into the holes 46 of each of the stacked discs 30 are provided so as not to obstruct the flow path of the valve cage 10, and a series of weld beads 48 on the outer circumference of the valve cage 10 (FIG. 1). (See) firmly holds each disk 30 that constitutes the laminate. each<u style="single">fluid</u>A curved corner 50 is formed in the entrance stage slot 36, and the curved corner portion 50 is formed.<u style="single">fluid</u>Entrance stage<u style="single">Slot 36</u>It prevents the flow through the disk from peeling off from the disk surface. Also, each<u style="single">Fluid inlet stage slot 36</u>The inner tapered side wall 52 is the fluid inlet stage<u style="single">Slot 36</u>Consists of the high-pressure recovery stage of. For example, facing<u style="single">taper</u>The side wall 52 extends toward the outer circumference of the disc at an internal angle of about 15 °. each<u style="single">Fluid inlet stage slot 36</u>A small but sufficiently large rear slot 54 is formed at the end of the stack to allow the flow path to communicate with the plenum 40 of the adjacent upper and lower disks. This will be described later.

Each fluid outlet stage slot 38 has a slot front 56 sized to communicate with the plenum 40 of adjacent discs at the top and bottom. Both side wall portions 58 of the flow path narrow toward the outer circumference 34 of the disk, and each flow path outlet stage slot 38 constitutes a low-voltage recovery stage. The combination of the high pressure recovery stage and the low pressure recovery stage reduces the generation of noise.

An article by Hans D. Baumann in the January and February 1984 issue of Noise Control Engineering, "Coefficients and Factors relating to Acrodynamic Sound Level. Generated by Throttling Valves) , in particular, as a prior art of the present application. In this article, noise energy is considered as a function of pressure recovery. According to this article, the noise effect (in other words, the ability to generate noise) is a function of the pressure ratio (pressure ratio between inlet and outlet) divided by the pressure recovery rate (FL value). The FL value is low in the rectification range, and the FL value approaches 1.0 at the fluid outlet that opens rapidly. The FL value can be lowered by the tapered flow path where the inlet flow path is narrow and narrows toward the exit. Lowering the FL value is effective in a flow path with a pressure ratio of 2: 1 or more that generates noise of 5 to 10 dB. However, when the pressure ratio is low (2: 1 or less) and the noise is 5 to 10 dB or less, a high FL value is desirable. Therefore, the range of slot dimensions and shape can be determined according to the range of pressure normally used in valves.

According to a preferred embodiment of the present invention, the pressure ratio in the fluid inlet stage slot 36 of each inlet is set to 2 or more to reduce noise generation. In addition, the pressure ratio at the fluid outlet stage slot 38 at each outlet is set to 2 or less to reduce noise generation. As a result, the valve cage 10 can reduce noise with high efficiency.

As shown in FIG. 2, the symbol A is attached to one end of the disk 30 and the symbol B is attached to the other end. These symbols A and B serve to indicate the orientation of each of the discs 30 stacked according to the present invention. Also, as can be seen from FIG. 2, each fluid inlet stage slot 36 is arranged symmetrically with respect to the plenum 40.<u style="single">It has not been</u>.. In particular, adjacent to the plenum end 42 on the left side of FIG.<u style="single">fluid</u>Entrance stage slot 36 is adjacent to the right plenum end 44<u style="single">fluid</u>It is closer to the plenum end 42 than the entrance stage slot 36. each<u style="single">fluid</u>The exit stage slots 38 are also arranged asymmetrically with respect to the plenum ends 42 and 44. This slot arrangement is one of the important features of the present invention, and when the disks 30 are stacked as shown in FIG. 3, each slot prevents an obstacle-free vertical flow path from being formed. Therefore, virtually every channel<u style="single">fluid</u>Each from entrance stage slot 36 through Plenum 40<u style="single">fluid</u>It is a flow path that goes out to the exit stage slot 38.

FIG. 3 shows an exploded perspective view of a partially laminated body formed of four identical discs 30, so that the positional relationship of each disc 30 can be easily understood. The valve cage 10 is configured by vertically stacking a partial laminate formed of the four discs 30 shown in FIG.

In FIG. 3, the lowermost disk 30a is installed in the same state as the disk 30 in FIG. 2, and the symbol B is visible on the upper surface thereof. The disc 30b above it is installed with the disc rotated 180 ° so that the symbol A of the disc 30b is above the symbol B of the disc 30a at the bottom. The disk 30c above it is placed with the disk 30 in FIG. 2 turned upside down so that the symbol B is above the symbol A on the disk 30b below it, and the symbol B on the disk 30c is not visible. Finally, the top disk 30d is placed with the disk 30 of FIG. 2 turned over so that the symbol A is above the invisible symbol B of the disk 30c below it, and the symbol A of the disk 30d is invisible. In this way, the symbols A of the invisible disc 30d and the symbol B of the disc 30c, and the symbols A of the visible disc 30b and the symbol B of the disc 30a are arranged in a row above and below, and the discs 30 are stacked. There is.

As mentioned above, the fluid inlet stage slot 36 and the fluid outlet stage slot 38 are asymmetric with respect to the alignment pin holes 46 and, in particular, the plenum ends 42, 44. Due to the asymmetrical arrangement of the fluid inlet stage slot 36 and the fluid outlet stage slot 38 and the selective arrangement of the disks 30a to 30d shown in FIG. 3, an unobstructed vertical flow path is not formed inside the disk laminate. Further, according to this configuration, it is possible to prevent resonance that occurs in a chamber having an unobstructed vertical flow path.

Next, FIGS. 4, 5 and 6 show the flow path of the fluid flowing three-dimensionally in the valve cage 10. For simplification of the description, the reference numerals of the discs 30b, 30c and 30d used in FIGS. 3 and 4 and superimposed on the bottom disc 30a are shown in FIGS. 5 and 6 for schematically explaining the flow path. Also used. First, the fluid enters each fluid inlet stage slot 36 through the central cavity 32. In order to simplify the figure and description, the flow path of the fluid flowing three-dimensionally from one fluid inlet stage slot 36 to a plurality of fluid outlet stage slots 38 will be described. The fluid flows three-dimensionally inside the disk laminate, but for convenience, the fluid inlet and outlet are shown on the same plane.

As an example, fluid flows into the fluid inlet stage slot 36a of disk 30b. The fluid flows into the rear slot portion 54 through between the tapered side walls 52, is divided into upper and lower parts from the rear slot portion 54, and flows into the plenum 40 of the lower disk 30a and the upper disk 30c. The fluid divided into upper and lower halves flows radially in the plenum 40a of the disk 30a and the plenum 40c of the disk 30c, respectively.

Then the fluid is each<u style="single">fluid</u>Reaching slot front 56 of exit stage slot 38. As an example, when each flow path in the plenum 40a and 40c reaches the slot front portion 56, it is divided into upper and lower parts and flows into the slot front portion 56a, one of which is the fluid outlet of the disk 30b.<u style="single">stage</u>Outflow through slot 38a. In the above, for convenience, two plenum<u style="single">40</u>One fluid that has passed through<u style="single">fluid</u>exit<u style="single">stage</u>slot<u style="single">38</u>One flow path flowing out of is described. However, in reality, the fluid flows radially within the plenum 40a and 40c, and is further divided into upper and lower parts.<u style="single">fluid</u>Disperse and flow out of the exit stage slot 38.

For example, as shown in FIG. 5, the fluid flowing into the disc 30b is divided into upper and lower halves and flows toward the lower disc 30a and the upper disc 30c, and the inside of the plenum 40a and 40c of each disc is radially outward. It flows. At the exit stage, for example, the fluid in the plenum 40c is partly in each of the front slots 56 of the lower disk 30b.<u style="single">fluid</u>Flows downward toward exit stage slot 38 (see Figure 6), with the remaining portion of the front slot of the upper disk 30d.<u style="single">56</u>Each of<u style="single">fluid</u>Exit stage slot<u style="single">38</u>It flows upward toward. Similarly, the fluid flowing outward in the radial direction in the plenum 40a is divided into upper and lower parts and flows into the upper disk 30b and the lower disk (the reference numerals are omitted in FIG. 5).

In FIG. 6, a plurality of fluids are dispersed in the circumferential direction and finally in the radial direction in the disks 30d, 30b and the disk in which the reference numerals are omitted in FIG.<u style="single">Fluid outlet stage</u>It shows the state of flowing out from slot 38. For example, the fluid in the plenum 40c is distributed circumferentially and passes through multiple front slots (56a, 56b, 56c, etc.) to multiple discs 30b.<u style="single">Fluid outlet stage slot</u>It flows out through 38a, 38b, 38c, etc. Therefore, in the apparatus of the present invention, a plurality of valves in the valve cage 10.<u style="single">Fluid outlet stage</u>slot<u style="single">38</u>With a large capacity plenum that feeds fluid to<u style="single">fluid</u>Exit stage slot<u style="single">38</u>Even if a part of the device is blocked by a foreign substance, the performance of the entire device is not significantly affected. This is a great advantage as compared with the conventional device using a bent flow path in which the entire flow is stopped when even one flow path is blocked. Also, as a preferred embodiment, each disc 30 has a plurality of fluid inlets.<u style="single">Stage slot</u>And fluid outlet<u style="single">Stage slot</u>Therefore, a smooth throttle and a linear property of the flow rate can be obtained, and a flow stagnation region does not occur unlike a conventional device having a bent flow path. If non-linear nature of the flow path and flow is desired, some discs<u style="single">Fluid inlet stage slot</u>as well as<u style="single">Fluid outlet stage slot</u>It can be achieved by changing the number of.

As can be seen from the embodiment of FIG. 2, the slots are not provided in a distributed manner in the circumferential direction, but form two slot groups. Also, to make the internal pressure equal<u style="single">Plenum</u>, Forming one large chamber eliminates the need for frequent frame / beam injection and stopping during machining. Moreover, the peripheral length (machining length) of the plenum can be remarkably shortened. By forming a group of slots, only one type of disc 30 is required to form a valve cage 10 by stacking them. The flow path inside the laminate can be formed by changing the orientation of the disc. It is also possible to form a group of two or more slots on the disk. Four discs having the two slot groups shown in FIG. 2 can form the partial laminate shown in FIG.

A disk having three slots can form a partial laminate with six discs. A proper arrangement of slots can reduce the number of discs to achieve a given decompression and reduce the size of the decompression member to simplify the shape.

In the disk 30 shown in FIG. 2, all the slot groups 36 and 38 are provided on one side in the circumferential direction of the disk, and the plenum 40 is provided on the other side. In another form of the disk 60 shown in FIG. 7, slots are arranged alternately. That is,<u style="single">Fluid inlet stage slot</u>62、<u style="single">Fluid outlet stage slot</u>64 and Plenum 66 are placed all around the disc. Plenum 66<u style="single">Fluid inlet stage slot</u>When<u style="single">Fluid outlet stage slot</u>It is placed between. According to the disc 60 shown in FIG. 7 in which the plenum and the slot group are alternately arranged, the two discs 60 can form a partial laminate in the laminate, and in the laminate,<u style="single">Fluid inlet stage slot</u>When<u style="single">Fluid outlet stage slot</u>Can form a three-dimensional flow at the same height. However, in the embodiment of FIG. 7, it is difficult to arrange the slots asymmetrically to prevent the upstream and downstream without obstacles. The advantage of alternating slots and plenums shown in Figure 7 is long<u style="single">Plenum 40, 76</u>This is to increase the rigidity of the disc as compared with the discs of FIGS. 2 and 8 having the above. Therefore, a large differential pressure can be taken.

In addition, as can be seen from Figure 7, each fluid outlet stage<u style="single">slot</u>At 64, the side 65 of the slot is parallel and not as inclined as the side 58 of the disc 30.<u style="single">Fluid outlet stage slot</u>The 64 parallel sides are less efficient in terms of noise suppression than the sloping sides. However, the parallel side surface can be easily processed by the conventional method as compared with the inclined side surface. Of course, if necessary<u style="single">Fluid outlet stage slot</u>The side surface of 64 can be inclined in the same manner as the disc 30, and the noise prevention efficiency can be improved.

Figure 8<u style="single">(a)</u>, Figure 8<u style="single">(b)</u>Shows yet another form of disc. Figure 8<u style="single">(a)</u>The disc 68 shown in is the fluid inlet.<u style="single">stage</u>Slot 70 and fluid outlet<u style="single">stage</u>Slots 72 are provided all around disk 68, in four groups (ie, four groups).<u style="single">fluid</u>entrance<u style="single">stage</u>Slots and<u style="single">fluid</u>exit<u style="single">stage</u>Slots) are formed. Figure 8<u style="single">(b)</u>The disc 74 shown in the above is a disc paired with the disc 68, and four plenum 76s are provided around the disc 74. On the discs 68 and 74, as in the above embodiment,<u style="single">Fluid inlet stage slot</u>When<u style="single">Fluid outlet stage slot</u>Four disks are required to form a partial laminate that forms a three-dimensional flow that prevents vertical flow inside the laminate with the same height.

Figure 8<u style="single">(a)</u>, Figure 8<u style="single">(b)</u>In the embodiment, unlike the above-described embodiment in which one type of disc is used, two types of discs are required. Further, unlike the above-described embodiment having a linear property, the flow resistance depends on the pushing amount of the valve plug.<u style="single">To</u>It cannot be changed smoothly.

<u style="single">fluid</u>Since the pressure drop and flow rate inside the decompressor are changed, the slot arrangement can be changed for each stacked disk. For example, the number of slots on one disk in the device can be reduced compared to the number of slots on another. This loses the advantages of one or two discs, but is desirable in that the flow characteristics (flow and throttle) can be changed.

FIG. 9 shows another form of disc 78 having a fluid inlet stage slot 80, a fluid outlet stage slot 82, and a plenum 84, and further having four openings 86 in the disc. The opening 86 is for connecting and stacking the discs 78 through the bolt 88. The weld beads shown in Fig. 1 are not required because they are laminated using bolts. In the present invention, the flow rate is not reduced because the bolt 88 passes through the plenum.

In the embodiment of the present invention described above,<u style="single">Fluid inlet stage slot</u>Fluid flowing in from through Plenum<u style="single">Fluid outlet stage slot</u>It has a two-stage structure that flows out from. But if necessary, more decompression steps<u style="single">slot</u>Can be provided.

Numerous decompression stages<u style="single">slot</u>As an example of a disk with, 7 steps of decompression steps are shown in Fig. 10.<u style="single">slot</u>The disc 90 having the above is shown, and FIG. 11 shows a perspective view of a partially laminated body using four discs 90. As shown in FIG. 10, the disk 90 has a flow path in the first stage.<u style="single">Fluid inlet stage slot</u>92, Plenum 94, 2nd stage<u style="single">Fluid inlet stage slot</u>96, 7th stage of the final stage from Plenum 98<u style="single">fluid</u>It is connected to the exit stage slot 100. As shown in Figure 10.<u style="single">Fluid inlet stage slot</u>92、96、<u style="single">Fluid outlet stage slot</u>100 forms multiple channels with contraction / expansion per slot length.

In the perspective view of FIG. 11,<u style="single">Fluid inlet stage</u>The fluid flowing in from slot 92 flows three-dimensionally inside the partial laminate composed of four disks 90.<u style="single">Fluid inlet stage</u>At the same height as slot 92<u style="single">Fluid outlet stage</u>Outflow from slot 100. The fluid has 7 decompression stages formed in the stack.<u style="single">slot</u>However, in principle, it is the same as the two-step decompression described above. That is, the fluid is one stage<u style="single">slot</u>From the adjacent disk slot, through the plenum to the next stage<u style="single">slot</u>It is supposed to move to. 7-stage decompression stage<u style="single">slot</u>The embodiment having is particularly effective for depressurizing the flow of liquid. However, in the laminated body, a large number of slot portions are likely to overlap to generate unwanted fluid upstream and downstream, and this problem can be solved by interposing a thin partition plate between the discs at each height in the laminated body. be able to. In addition, decompression stage of 3 to 6 stages (or 7 stages or more)<u style="single">slot</u>Implementation of the embodiment with will be easy for those skilled in the art.

The above detailed explanation is for ease of understanding, and any limitation or improvement regarding this is obvious to those skilled in the art.

In the above, the application of the fluid pressure reducing device of the present invention to the flow control valve has been described, but the application of the present invention is not limited to this. The device of the present invention can be provided on the upstream side or the downstream side of the valve as a flow rate suppressing device fixed in the pipe, or can be provided at a position independent of the flow rate control valve.

The novel features of the present invention are described in each claim. The present invention will be clarified by detailed description based on the accompanying drawings. In some figures, the same reference numerals are used for similar members.<figref num="1">It is sectional drawing of the flow rate control valve which built in the disk laminated type valve cage which forms the fluid pressure reducing device of this invention.</figref><figref num="2">It is a top view of the disk which forms the disk laminate shown in FIG.</figref><figref num="3">FIG. 5 is a perspective view of an embodiment of the present invention in which four discs shown in FIG. 2 are stacked in different directions to form a partially laminated body.</figref><figref num="4">It is a partial perspective view of the disk laminate shown in FIG. 1, and conceptually shows the flow of the fluid passing through the inside thereof.</figref><figref num="5">It is a conceptual diagram of the flow in a disk stack seen from the side.</figref><figref num="6">It is a conceptual diagram of the flow in a disk stack seen from above.</figref><figref num="7">It is a top view of the disk of another embodiment in which slots and plenum are arranged alternately.</figref><figref num="8(a)">FIG. 5 is a plan view of each disc of yet another embodiment, in which all slots are provided on one disc and plenum on the other disc.</figref><figref num="8(b)">FIG. 5 is a plan view of each disc of yet another embodiment, in which all slots are provided on one disc and plenum on the other disc.</figref><figref num="9">FIG. 5 is a plan view of a disc of yet another embodiment having bolts that keep the discs stacked.</figref><figref num="10">FIG. 5 is a plan view of a disk of yet another embodiment having a plurality of fluid processing steps.</figref><figref num="11">It is a partial perspective view of the embodiment of the present invention in which four discs shown in FIG. 10 are stacked in different directions to form a partially laminated body.</figref>

10 valve basket 12 Flow control valve 14 Valve box 16 Fluid inlet 18 Fluid outlet 30 discs 32 Central cavity 34 Circumference 36 Fluid inlet stage slot 38 Fluid outlet stage slot 40 Plenum 54 Rear slot 56 Slot front