Abstract:
The present invention relates to an aperture-shaped variable valve which is attached to the inside or end of a pipe to variably control the flow rate or pressure of fluid, such as liquid or gas, flowing along the pipe. As to one usage of the invention, the exhaust noise of an automobile can be controlled because back pressure is variably controlled by the valve attached to a vehicular exhaust system where the flow rate of exhaust gas varies according to the RPM of an engine. Additionally, the flow rate can be measured within a large range through application of the valve to a flowmeter. An operational principle of the valve is to control the cross section of the flow path by contract or release of aperture plates which are initially opened at a constant size by elasticity of a spring. Using the aperture-shaped variable valve, linear control of flow rate or pressure is facilitated, compared with a conventional disc variable valve. Furthermore, control of flow rate or pressure is enabled by a simple method so constitution of a control system is facilitated.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a valve which controls a flow rate of fluid, and more particularly, to an aperture-shaped variable valve which is attached to the inside or end of a pipe to variably control the flow rate or pressure of fluid, such as liquid or gas, changing the flow rate at any time and flowing along the pipe. 
       BACKGROUND ART 
       [0002]    Typical control valves including disc variable valves used for the purposes of controlling the flow rate hardly control the flow rate precisely since the location of the opening/closing part of the valves and the open area of the flow path are not linearly related. Also, the shape of the flow path inside the valve drastically changes to fluctuate the velocity and pressure of fluid to thereby cause a turbulent flow, resulting in great pressure loss, flow noise and vibration. If the fluid is liquid, a very low pressure is partially formed inside the fluid and the separated gas of the liquid generates cavitations. To control the typical valves as above, an additional motor is required to rotate the rotation part of the valves and the control system becomes complicated. 
         [0003]    As to one usage of the variable valve, a disc variable valve which is used for an automotive exhaust system is attached to a first end of an exhaust pipe as shown in (a) in  FIG. 1 . Automotive muffler is used to reduce exhaust noise by gradually decreasing the pressure of exhaust gas since high temperature and high pressure pulsating exhaust gas causes great noise due to a drastic change in pressure if being emitted to the atmosphere as is. If the pressure of the exhaust gas emitted from the muffler (“back pressure”) increases, the exhaust noise is reduced, but exhaust resistance increases and the engine power drops. By contrast, if the exhaust resistance is reduced to prevent the power loss of the engine, the exhaust noise aggravates. Accordingly, if the variable valve is attached to the exhaust gas discharger, back pressure increases in a low speed area where the exhaust noise is important, and decreases in the medium and high speed area where the engine power is important, to thereby solve the foregoing problem which arises in the design of the muffler. 
         [0004]    As shown in (b) in  FIG. 1 , a valve plate of a conventional disc variable valve which is used for an automotive muffler is initially closed by a spring and open when back pressure rises to exceed the force of the spring with the flow rate increase. It is important to understand the correlation between the back pressure according to the flow rate and a spring constant to apply the variable valve to the muffler. However, in the case of a conventional disc variable valve, an opening area does not linearly increase according to an opening angle of the disc and it is very difficult to calculate the flow rate which is discharged through the opening area. Accordingly, a lot of tests should be conducted for diameters of exhaust pipes in which valves are attached with respect to various engines to identify the correlation between the back pressure and the spring constant, and each test formula should be found. Thus, it is not easy to manufacture an appropriate variable valve, and the common application of manufactured variable valves to other mufflers is limited. 
         [0005]    In the case of the disc variable valve, opening the valve makes the flow path very complicated, and the flow of the fluid drastically changes, and causes noise and vibration due to a turbulent flow. To that respect, the variable valve may reduce the pulsating noise from the engine, but the flow noise from the variable valve increases, and the overall improvement for the exhaust noise is not that great or may become worse. 
         [0006]    Conventional flowmeters which measure the flow rate through a differential pressure by using a ventury tube or nozzle has its cross sectional area fixed to measure the differential pressure, and are not appropriate for measuring a wide range of flow rates. If a wide range of flow rates should be measured, at least two flowmeters which have different ranges should be used simultaneously or sequentially measure the flow rate to overlap a part of the measurement range. In the former case, the flowmeters cannot be used adjacently in a desired location due to an interference of the flow. In the latter case, the adjustment of the overlapping range after the measurement is required and the flowmeters should be replaced. 
         [0007]    To solve the problem of the typical control valve, the applicant filed application for “aperture-shaped active control variable valve” with Korean Patent Application No. 10-2007-0048965. This invention arranges a plurality of aperture plates in a ring shape on an aperture frame to have a semi-spherical or cone shape so that the valve is attached to the inside or end of the pipe in which fluid flows. The valve includes a means to apply a consistent force to an aperture surface including a plurality of aperture plates to control the exit diameter of the aperture and control the flow rate or pressure. 
         [0008]    The present invention is an improved invention of Korean Patent Application No. 10-2007-0048965. 
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Technical Problem 
       [0009]    As described above, a control system which controls the flow rate or pressure by using conventional control valves hardly performs a linear control of the flow rate or pressure, and accompanies great pressure loss, flow noise and vibration and has a complicated configuration. 
         [0010]    Accordingly, as a valve used for a flow rate control system, a variable valve is required to efficiently control the flow rate or pressure linearly, reduce pressure loss inside the valve, generate less flow noise and vibration, and enable a simpler control system. 
         [0011]    The present invention relates to an active control and semi-active control flow rate valve which solves the foregoing technical problem. 
       Technical Solution 
       [0012]    An aperture-shaped variable valve according to the present invention has a plurality of aperture plates arranged in a ring shape by overlapping each other on an aperture frame to form a semi-spherical or cone aperture surface. A hinge is formed in a front side of the valve in the aperture frame to maintain a predetermined entrance diameter, and a discharger is formed in an opposite direction of the aperture frame as a rear side of the valve to vary a diameter of an opening. 
         [0013]    The aperture-shaped variable valve according to the present invention includes various shapes of control means to control the aperture surface formed by overlapping aperture plates, and a restoring means to recover the size of the discharger of the aperture if the control force applying to the aperture surface is released to thereby adjust the diameter of the discharger and control the flow rate or pressure of a pipe path in which the valve is installed. 
       Advantageous Effect 
       [0014]    The aperture-shaped variable valve according to the present invention may control the flow rate or back pressure linearly and reduce the pressure loss and flow noise, compared to a conventional disc variable valve. 
         [0015]    The aperture-shaped variable valve according to the present invention may be attached to the inside or end of the pipe to variably control the flow pressure of fluid changing the flow rate at any time and flowing along the pipe. 
         [0016]    The aperture-shaped variable valve according to the present invention may use a simple actuator performing a rectilinear movement to adjust an opening area of the valve as the discharger area by various tools and methods and to easily form a flow rate or pressure control system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  illustrates a disc variable valve attached to a muffler and a general shape of the disc variable valve. 
           [0018]      FIG. 2  illustrates a general shape of an aperture-shaped variable valve and the aperture-shaped) variable valve which is attached to a pipe. 
           [0019]      FIG. 3  illustrates an aperture-shaped variable valve which includes a control wire. 
           [0020]      FIG. 4  illustrates an aperture plate which includes an aperture surface of the aperture-shaped variable valve. 
           [0021]      FIG. 5  illustrates an aperture-shaped variable valve which includes a control ring. 
           [0022]      FIG. 6  illustrates an aperture-shaped variable valve which includes a control bar. 
           [0023]      FIG. 7  illustrates an aperture-shaped variable valve which includes a rear control ring and is installed to the pipe. 
           [0024]      FIG. 8  illustrates an aperture-shaped variable valve which includes an elastic layer. 
           [0025]      FIG. 9  illustrates an aperture-shaped variable valve which includes a restoring ring. 
       
    
    
     MAJOR REFERENCE NUMERALS 
       [0026]      10 : aperture frame,  20 : aperture plates,  30 : restoring spring,  35 : restoring means 
         [0027]      35 - 1 : elastic layer,  35 - 2 : spring,  35 - 3 : restoring ring,  35 - 4 : guide 
         [0028]      40 : spring support,  50 : control wire,  60 : control ring,  70 : control bar, 
         [0029]      80 : rear control ring 
       MODES FOR CARRYING OUT THE INVENTION 
       [0030]    An aperture-shaped variable valve according to the present invention is shaped as in (a) in  FIG. 2 , and may be attached to the end of a pipe which requires a flow rate control as in (b) in  FIG. 2  or inside the pipe as in (c) in  FIG. 2 . 
         [0031]    As shown in (a) in  FIG. 3 , an active control aperture-shaped variable valve which actively controls the flow rate and pressure of fluid flowing along the pipe by controlling an opening area of the valve (a control valve having the above function is called “active control valve,” which applies to this specification) includes a ring-shaped aperture frame  10 , a plurality of aperture plates  20  which is arranged in a ring shape on an aperture frame to form an aperture, a restoring spring which is attached to the aperture plates and supplies the restoring force to the aperture plates, a spring support  40  which fixes the restoring spring  30 , and a control device  50  which controls the opening area of the aperture formed by the plurality of aperture plates  20 . 
         [0032]    As shown in  FIGS. 8 and 9 , a semi-active control aperture-shaped variable valve which passively changes an opening area of the valve depending on the extent of the pressure of the fluid flowing along the pipe with respect to an aperture surface (a control valve having the above function is called “semi-active control valve,” which applies to this specification) includes an aperture frame  10 , aperture plates  20  and a restoring means provided in the outside of the aperture surface formed by the aperture plates  20  like the active control aperture-shaped variable valve. 
         [0033]    The aperture frame  10  is provided in an upstream of the valve and may be manufactured in a ring shape by using a bar whose cross section is a circle so that the aperture plates  20  fit thereinto and rotate. 
         [0034]    As shown in  FIG. 4 , the aperture plates  20  include thin metal plates or plastic plates, and are manufactured by forming a hinge hole  22  coupled to the aperture frame  10  in a first end of an aperture plate body  21  shaped like a curved surface forming a part of a spherical, oval (a sphere whose cross section is oval like a rugby ball) or cone surface. A rear support  25  extends from the hinge hole  22  to be coupled to the restoring spring  30 . A spring seat  23  is formed in the rear support  25 . Gap adjustment pieces  24  are formed in opposite ends of the rear side of the aperture plate body  21 . 
         [0035]    The aperture frame  10  may be manufactured as a washer type ring having a large diameter and a narrow width instead of using a ring bar whose cross section is a circular shape. In this case, a plurality of slits may be formed in the ring to insert the rear support  25  of the aperture plates  20  thereinto. Then, the slits of the aperture frame  10  act as a hinge, and the aperture plates  20  which are inserted into the slits do not move along a circumferential direction of the aperture frame  10 , which does not require additional gap adjustment pieces  24  for the aperture plates  20 . 
         [0036]    If the aperture plates  20  are manufactured by metal plates such as stainless steel, the metal plate is cut by press and the part of the plate is cut and folded to form the hinge hole  22  and the gap adjustment pieces  24 . 
         [0037]    The aperture plates  20  are fit so that the gap adjustment pieces  24  of the aperture plates  20  contact each other along the circumference of the aperture frame  10 , and form a semi-spherical, semi-oval or cone-shaped aperture having a discharger in a downstream thereof. 
         [0038]    The restoring spring  30  is fixed between the spring seat  23  formed in the rear side of the aperture plates  20  and the spring support  40 . The restoring spring  30  is coupled to each of the aperture plates  20  and applies the force to the aperture plates  20  in the opening direction of the aperture. 
         [0039]    The restoring spring  30  includes a compressed coil spring which always presses the rear support  25  of the aperture plates  20 . 
         [0040]    The restoring spring  30  may further include a torsional spring or a clip spring which has a first end fixed to the aperture frame  10  and a second end contacting the aperture plates  20  and allows the aperture formed by the aperture plates  20  to maintain an opening state. The torsional spring or clip spring may be coupled to the spring seat  23  formed by cutting a part of the hinge hole  22  of the aperture plates  20  and inserted into the aperture frame  10  together with the aperture plates  20 . Then, the spring support  40  may be omitted and a simpler control system may be provided. 
         [0041]    The spring support  40  has a aperture          -shaped ring and is fixed to the pipe which employs the valve according to the present invention. The spring support  40  may be separately manufactured and coupled to the aperture frame  10  or may be integrally formed in the aperture frame  10 . 
         [0042]    The restoring spring  30  may vary by specially designing a connection of the spring support  40  and the aperture plates  20  other than the restoring spring as above. 
         [0043]    The control device  50  reduces or enlarges the area of the discharger of the aperture by applying the force to the aperture surface formed by overlapping a plurality of aperture plates  20 , and may vary. 
         [0044]    As shown in  FIG. 3 , the control device  50  according to an exemplary embodiment may include a control wire  50  which is installed in the middle of the body of the aperture. A first end of the control wire  50  may be fixed and a second end thereof may be connected to an actuator which pulls and releases the control wire  50 . If the control wire  50  is pulled, the aperture plates  20  overcome the force of the restoring spring  30  and reduce the discharger of the aperture. If the control wire  50  is released, the restoring spring  30  of the aperture plates  20  applies the force to the aperture plates  20  and extends the discharger. 
         [0045]    In the active control variable valve which uses the control wire  50  as above, a semi-active control variable valve may be formed by connecting the first end of the control wire  50  to a fixed control spring (not shown), instead of connecting the first end of the control wire  50  to the actuator. That is, if the pressure of the fluid flowing along the pipe increases and a reaction force of the inside of the aperture exceeds the force of the control spring connected to the control wire  50  controlling the aperture surface, the control spring extends and the control wire  50  is released to extend the discharger of the aperture. If the flow pressure decreases and the reaction force inside the aperture becomes smaller than the force of the control spring, the control wire  50  returns to its original location and reduces the discharger by the restoring elastic force of the control spring. That is, the rising pressure of the fluid flowing along the pipe extends the discharger and the pressure is reduced. If the pressure of the fluid flowing along the pipe decreases, the discharger is reduced and the pressure increases to thereby control the flow pressure semi-actively. 
         [0046]    If a bypass pipe is connected to an entrance of the pipe in which the variable valve is attached, a rising flow pressure opens the discharger and the fluid flows to the pipe having the variable valve installed therein, and the flow rate inside the bypass pipe decreases. If the flow pressure decreases, the flow rate increases again. The flow rate and the flow pressure are interdependent and may be controlled at the same time. Even in such a case, the valve according to the present invention may control the flow rate and pressure individually or collectively. 
         [0047]    The difference between the active control and the semi-active control is as follows: In the case of the active control, the control device actively operates by an external force instead of the pressure of the fluid, and an artificial control is available after the valve is attached to the pipe. In the case of the semi-active control, the aperture plates or the control device operates by the pressure of the fluid only, and an artificial control is not available after the valve is attached to the pipe. 
         [0048]    As shown in  FIG. 5 , a control device according to another exemplary embodiment employs a control ring  60  which moves to the upstream or downstream along a central axis of the variable valve. If the control ring  60  moves to the upstream whose diameter is larger than the downstream, the aperture plates  20  of the aperture overcome the force of the restoring spring  30  and reduce the discharger of the aperture. If the control ring  60  moves to the downstream whose diameter is smaller than the upstream, the restoring spring  30  of the aperture plates  20  applies the force to the aperture plates  20  to extend the discharger. 
         [0049]    In the active control valve which uses the control ring  60  as above, a semi-active control variable valve may be formed by installing a control spring (not shown) applying a consistent force to the upstream of the valve instead of fixing the control ring  60  to the actuator. That is, if the pressure of the fluid flowing along the pipe increases and the reaction force inside the aperture exceeds the force of the control spring connected to the control ring  60  controlling the aperture surface, the control spring extends or compresses and moves to the downstream and extends the discharger of the aperture. If the flow pressure decreases and the reaction force inside the aperture becomes smaller than the force of the control spring, the control ring  60  returns to its original position and the discharger is reduced by the restoring elastic force of the control spring. 
         [0050]    As shown in (a) in  FIG. 6 , a control device according to another exemplary embodiment may be provided by installing a control bar  70 - 1  in the middle of the aperture. An end of the control bar  70 - 1  is shaped like a circular arc to surround the aperture. If opposite ends of the control bar  70 - 1  are pressed, the aperture plates  20  overcome the force of the restoring spring  30  and reduces the discharger of the aperture. If the force pressing the control bar  70 - 1  is removed, the restoring spring  30  applies the force to the aperture plates and extends the discharger. If the aperture plates are pressed by the control bar  70 - 1 , the upper and lower aperture plates of the aperture are pressed directly, but the pressure is transmitted to other adjacent aperture plates as the aperture plates  20  overlap each. Thus, all of aperture plates move and reduce the discharger. 
         [0051]    Instead of pressing the opposite ends of the control bar  70 - 1 , a control bar  70 - 2  whose opposite ends are pulled may be provided as shown in (b) in  FIG. 6 . 
         [0052]    In the active control valve which uses the control bar  70 - 1  or  70 - 2 , a semi-active control variable valve may be provided by installing a control spring (not shown) pressing or pulling the control bar  70 - 1  or  70 - 2  instead of fixing the control bar  70  to the actuator. That is, if the pressure of the fluid flowing along the pipe increases and the reaction force inside the aperture exceeds the force of the control spring connected to the control bar  70 - 1  or  70 - 2  controlling the aperture surface, the control spring extends or compresses and the control bar  70 - 1  or  70 - 2  are pulled or pressed upwards/downwards to extend the discharger of the aperture. If the pressure of the fluid decreases and the reaction force inside the aperture becomes smaller than the force of the control spring, the control bar  70 - 1  or  70 - 2  return to their original position and reduce the discharger by the restoring elastic force of the control spring. 
         [0053]    As shown in  FIG. 7 , a control device according to another exemplary embodiment may extend the rear side of the aperture plates  20 , employ a rear control ring  80  in the rear side of the valve, and move the rear control ring  80  to the upstream or downstream along a central axis of the variable valve. If the rear control ring  80  moves to the downstream, the aperture plates  20  of the aperture overcome the force of the restoring spring  30  and reduce the discharger of the aperture. If the rear control ring  80  moves to the upstream, the restoring spring  30  of the aperture plates  20  applies the force to the aperture plates  20  to extend the discharger. 
         [0054]    In the active control valve which uses the rear control ring  80  as above, a semi-active control valve may be provided by installing a control spring (not shown) applying the force toward the downstream of the valve instead of fixing the rear control ring  80  to the actuator. That is, if the pressure of the fluid flowing along the pipe increases and the reaction force inside the aperture exceeds the force of the control spring connected to the rear control ring  80  controlling the aperture surface, the control spring extends or compress and the rear control ring  80  moves to the upstream and extends the discharger of the aperture. If the pressure of the fluid decreases and the reaction force inside the aperture becomes smaller than the force of the control spring, the rear control ring  80  returns to its original position and reduces the discharger by the restoring elastic force of the control spring. 
         [0055]    As shown in  FIG. 8  or  9 , a semi-active control aperture-shaped variable valve is provided by installing a restoring means outside the aperture surface, excluding the control device  50 ,  60 ,  70  or  80  from the active control aperture-shaped variable valve. If the restoring spring  30  is not used, the valve becomes a variable valve whose discharger is completely closed when there is no pressure to the aperture surface. If the restoring spring  30  is used, the valve becomes a variable valve whose discharger has a minimum area when the force of the restoring spring to open the aperture and the force of the restoring means to close the aperture are equal. 
         [0056]    As shown in  FIG. 8 , the restoring means according to an exemplary embodiment may include an elastic layer  35 - 1 . The elastic layer  35 - 1  may be manufactured with a rubber layer to surround the external surface of the aperture and be fixed to the aperture frame  10 . 
         [0057]    The elastic layer  35 - 1  has the discharger of the aperture maintain its reduced size and extends the discharger of the aperture if the inside of the aperture receives the reaction force by the pressure of the fluid flowing along the pipe. If the pressure of the fluid decreases, the elastic layer  35 - 1  contracts and the discharger of the aperture is reduced. 
         [0058]    That is, if the pressure of the fluid flowing along the pipe increases, the discharger extends and the pressure of the fluid decreases. If the pressure of the fluid flowing along the pipe decreases, the discharger is reduced and the pressure of the fluid increases to thereby control the pressure of the fluid semi-actively. 
         [0059]    If the elastic layer  35 - 1  is used as a restoring means, it acts as a restoring spring and concurrently prevents the fluid from leaking between the aperture plates to thereby control the flow rate and pressure more precisely. 
         [0060]    As shown in  FIG. 9 , a restoring means according to another exemplary embodiment may include a spring  35 - 2  and a restoring ring  35 - 3 . The restoring ring  35 - 3  fits into the outside of the aperture surface and is connected to the aperture frame  10  by the spring  35 - 2 . 
         [0061]    The restoring ring  35 - 3  is pulled to the front side of the valve by the spring  35 - 2  to reduce the discharger of the aperture, and then overcomes the tension of the spring  35 - 2  and moves to the discharger of the aperture, and expand the discharger of the aperture as the inside of the aperture is affected by the pressure of the fluid flowing along the pipe to extend the aperture. If the pressure of the fluid decreases, the spring  35 - 2  compresses and pulls the restoring ring  35 - 3  to the front side of the valve and reduces the discharger of the aperture. 
         [0062]    If the spring  35 - 2  includes a guide  35 - 4  therein, it extends and compresses on an axial line in the direction of the guide  35 - 4  and ensures a more stable movement of the restoring ring  35 - 3 . The guide  35 - 4  is generally provided inside the spring  35 - 2 , but not limited thereto. Alternatively, the guide  35 - 4  may surround the outside the spring  35 - 2  and is applicable to all of restoring elastic members of the control device. 
         [0063]    The semi-active control aperture-shaped variable valve which employs the restoring ring  35 - 3  should be installed in a place where the inclination of the aperture surface is predetermined or more so that the restoring ring slides along the surface of the aperture plates and moves backward while the aperture plates  20  are unfolded. To decrease the coefficient of friction between the restoring ring  35 - 3  and the aperture surface, a lubricant may be applied between the restoring ring  35 - 3  and the aperture surface, or a bearing may be installed inside the restoring ring  35 - 3 . 
         [0064]    If the temperature of the fluid is not high and the fluid does not corrode rubber, the restoring spring may include raw rubber or synthetic rubber instead of a metal spring. Instead of the spring, a permanent magnet or an electromagnet may be used to generate the restoring force by the attraction or repulsion of the magnet. 
       INDUSTRIAL APPLICABILITY 
       [0065]    An aperture-shaped control valve according to the present invention may be used to control an automotive exhaust noise by variably controlling the back pressure of the automotive exhaust system where the flow rate of the exhaust gas varies depending on the RPM of the engine. 
         [0066]    If the aperture-shaped control valve according to the present invention is used in a flowmeter, a cross section may vary depending on the range of measurement of the flow rate and a wide range of flow rates may be measured by a single flowmeter. 
         [0067]    If the aperture-shaped control valve according to the present invention is used in a rocket propellant or rocket which receives a propellant force by emission of combustion gas, the quantity and pressure of the emitted combustion gas may be easily controlled.