Abstract:
The present invention relates to a balancing valve spool and a pressure regulating valve comprising the balancing valve spool. The balancing valve spool comprises a valve rod; a piston sleeve fixed on the valve rod; and a fixing piece sleeved between the valve rod and the piston sleeve and arranged along a direction in parallel with an axis of the valve rod. In one embodiment of the present invention, by connecting the fixing piece onto an actuator of the valve and arranging the fixing piece between the valve rod and the piston sleeve along the direction of the axis of the valve rod, an effect of guiding the valve rod is achieved and a sealing effect of isolating inlet pressure and outlet pressure is simultaneously achieved. Compared with the related arts, this design has the advantage of simple structure.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention belongs to the field of fluid control, specifically relates to a balancing valve spool and further relates to a pressure regulating valve comprising the balancing valve spool. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the design of a pressure regulator, since inlet pressure acts on a valve seat to produce an additional force which directly influences the performance of a pressure regulator product, a structure of a balancing valve spool is usually designed. 
         [0003]      FIG. 1  shows a designing method of a balancing valve spool at present. In this designing method, one end of an n-shaped diaphragm is fixedly connected with a valve rod and the other end of the n-shaped diaphragm is fixedly connected with a valve body or a connecting piece (for connecting the valve body with an actuator), wherein the end, which is connected with the valve rod, of the n-shaped diaphragm needs to be fixed on the valve rod by using a fixing piece. From  FIG. 1 , it can be seen that this balancing valve spool has the disadvantages of complex structure, the greater number of parts and relatively higher cost. 
         [0004]      FIG. 2  is another designing method of a balancing valve spool at present. This designing method adopts a valve rod mobile piston structure, wherein an O-ring  20  is arranged on a piston sleeve to achieve a sealing effect of isolating inlet pressure and outlet pressure. However, this kinds of structure is not beneficial to guide (since the O-ring has elasticity, the valve rod will shake); and in addition, the smoothness of a cylindrical surface, in contact with the O-ring, of the piston sleeve is difficult to guarantee, a guide sleeve  30  needs to be additionally arranged for the purpose of guide, an additional space needs to be added in a longitudinal space of the valve in order to install the guide sleeve and thereby the structure of the valve is more complex. 
       SUMMARY OF THE INVENTION 
       [0005]    In order to solve the problem that the structure of the existing balancing valve spool is complex, the present invention provides a balancing valve spool and a pressure regulating valve comprising the balancing valve spool. 
         [0006]    In one aspect, the embodiment of the present invention discloses a balancing valve spool, comprising:
       a valve rod;   a piston sleeve fixed on the valve rod; and   a fixing piece sleeved between the valve rod and the piston sleeve and arranged along a direction in parallel with an axis of the valve rod.       
 
         [0010]    The above-mentioned piston sleeve comprises a sleeve body and a bottom portion, the bottom portion of the piston sleeve is fixed on the valve rod and a first gap is configured between an inner wall of the sleeve body of the piston sleeve and an outer wall of the valve rod. 
         [0011]    A first sealing part is arranged between the above-mentioned fixing piece and the sleeve body of the piston sleeve. 
         [0012]    In another aspect, the embodiment of the present invention discloses a pressure regulating valve, comprising:
       a valve body provided with a valve chamber;   an actuator fixedly connected with the valve body; and   the above-mentioned balancing valve spool.   The above-mentioned fixing piece is fixedly connected onto the actuator.   The above-mentioned actuator comprises:   a pressure regulating device;   a diaphragm cap assembly comprising a first diaphragm cap and a second diaphragm cap, the first diaphragm cap being connected with the pressure regulating device, the second diaphragm cap being connected with the valve body, and the first diaphragm cap and the second diaphragm cap being matched with each other to form a hollow internal portion; and   a diaphragm assembly comprising a diaphragm, the diaphragm being located between the first diaphragm cap and the second diaphragm cap.       
 
         [0021]    The above-mentioned fixing piece is fixed on the second diaphragm cap; or the fixing piece and the second diaphragm cap are integrally molded. 
         [0022]    The above-mentioned pressure regulating valve further comprises guide sleeves which are fixed on the second diaphragm cap and the guide sleeves are rings which surround a cross section of the valve rod. 
         [0023]    Alternatively, the above-mentioned pressure regulating valve further comprises guide sleeves which are located on an outer circumference of the valve rod. 
         [0024]    The number of the above-mentioned guide sleeves is at least two. 
         [0025]    The bottom portion of the above-mentioned piston sleeve comprises an extending portion which extends outwards along an axis direction of the valve rod and the extending portion is closely fixed onto the valve rod. 
         [0026]    The above-mentioned valve rod and the piston sleeve are integrally molded. 
         [0027]    A second sealing part is arranged at a connection between the above-mentioned valve rod and the bottom portion of the piston sleeve. 
         [0028]    In one embodiment of the present invention, by connecting the fixing piece onto the actuator of the valve and arranging the fixing piece between the valve rod and the piston sleeve along the axis direction of the valve rod, an effect of guiding the valve rod is achieved and a sealing effect of isolating inlet pressure and outlet pressure is simultaneously achieved. Compared with the related arts, this design has the advantage of simple structure. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a structural schematic diagram of a balancing valve spool of a first one of related arts; 
           [0030]      FIG. 2  is a structural schematic diagram of a balancing valve spool of a second one of related arts; 
           [0031]      FIG. 3  is a structural schematic diagram of a balancing valve spool provided by a first one of embodiments of the present invention; 
           [0032]      FIG. 4  is a structural schematic diagram of a pressure regulating valve provided by a first one of embodiments of the present invention; 
           [0033]      FIG. 5  is a structural schematic diagram of a balancing valve spool provided by a second one of embodiments of the present invention; 
           [0034]      FIG. 6  is a structural schematic diagram of a balancing valve spool provided by a third one of embodiments of the present invention. 
       
    
    
     DESCRIPTION OF NUMERAL REFERENCES 
       [0035]      11 -valve rod,  111 -first end,  112 -second end,  12 -piston sleeve,  121 -sleeve body,  122 -bottom portion,  123 -extending portion,  13 -valve seat,  14 -fixing piece, A-first gap, B-second gap, C-third gap, D-fourth gap,  15 -first sealing part,  16 -second sealing part,  17 -guide sleeve,  2 -valve body,  21 -inlet,  22 -outlet,  23 -valve chamber,  231 -first area,  232 -second area,  233 -valve port,  311 -first diaphragm cap,  312 -second diaphragm cap,  321 -diaphragm,  322 -first diaphragm plate,  323 -second diaphragm plate,  331 -spring,  332 -regulating rod,  3321 -third end,  3322 -fourth end,  4 -third sealing part. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0036]    The technical solution of the present invention will be further described below in combination with the drawings and the embodiments. 
         [0037]    A balancing valve spool disclosed by this embodiment is located in a pressure regulating valve. As shown in  FIG. 4 , the pressure regulating valve comprises a valve body, the balancing valve spool and an actuator. The valve body  2  comprises an inlet  21 , an outlet  22  and a valve chamber  23 . The actuator is fixedly connected with the valve body. Inlet pressure of the pressure regulating valve provided by the present disclosure can be gas pressure and can also be liquid pressure. Correspondingly, outlet pressure can be gas pressure and can also be liquid pressure. 
         [0038]    As shown in  FIG. 3  and  FIG. 4 , the balancing valve spool comprises a valve rod  11 , a piston sleeve  12 , a valve seat  13  and a fixing piece  14 . The valve rod  11  comprises a first end  111  and a second end  112 , wherein the first end  111  of the valve rod is placed in the actuator of the valve and the second end  112  of the valve rod is fixed in the valve seat  13 . The valve seat  13  is movably arranged in the valve chamber  23 . The piston sleeve  12  comprises a sleeve body  121  and a bottom portion  122 , wherein the bottom portion  122  of the piston sleeve is fixed on the valve rod  11  and a first gap A is configured between an inner wall of the sleeve body of the piston sleeve and an outer wall of the valve rod. The fixing piece  14  is fixed on the actuator of the valve and the fixing piece  14  is arranged between the valve rod  11  and the piston sleeve  12  along an axis direction of the valve rod. The valve rod  11 , the piston sleeve  12  and the valve seat  13  can move along the axis direction of the valve rod. 
         [0039]    The fixing piece  14  herein has an effect of guiding the valve rod  11  and simultaneously has a sealing effect of isolating inlet pressure and outlet pressure. In order to guarantee the sealing effect, a first sealing part  15  can be arranged between the fixing piece  14  and the sleeve body  121  of the piston sleeve  12 . The first sealing part  15  can be an O-ring and can also be sealing packing, etc. It needs to be stated that the seal described here is a dynamic seal as the fixing piece  14  and the piston sleeve  12  move relatively. The purpose of isolating the inlet pressure and the outlet pressure is to enable the pressure regulating valve to maintain stable outlet pressure. However, the inlet pressure is certainly higher than the outlet pressure. If the inlet pressure and the outlet pressure are not isolated, the outlet pressure will always rise. 
         [0040]    In order to guarantee the valve rod  11 , the piston sleeve  12  and the valve seat  13  to move along the axis direction of the valve rod, as shown in  FIG. 3 , in this embodiment, a second gap B is configured between the fixing piece  14  and the bottom portion  122  of the piston sleeve, a third gap C is configured between the actuator of the pressure regulating valve and the piston sleeve and a fourth gap D is configured between the valve body and the piston sleeve. 
         [0041]    The valve chamber  23  comprises a first area  231  communicated with the inlet  21 , a second area  232  communicated with the outlet  22 , and a valve port  233  communicated with the first area  231  and the second area  232 . When the valve rod  11  moves, the valve seat  13  moves between the valve port  233  and the second area  232 . 
         [0042]    The actuator comprises a diaphragm cap assembly, a diaphragm assembly and a pressure regulating device, wherein the diaphragm cap assembly comprises a first diaphragm cap  311  and a second diaphragm cap  312 , the first diaphragm cap  311  is connected with the pressure regulating device, the second diaphragm cap  312  is connected with the valve body  2 , and the first diaphragm cap  311  and the second diaphragm cap  312  are matched with each other to form a hollow internal portion. The diaphragm assembly comprises a diaphragm  321 , a first diaphragm plate  322  and a second diaphragm plate  323 , the diaphragm  321  is pressed between the first diaphragm plate  322  and the second diaphragm plate  323 , the diaphragm  321  is located between the first diaphragm cap  311  and the second diaphragm cap  312 , the first diaphragm plate  322  is located within a cavity formed by the diaphragm  321  and the first diaphragm cap  311 , and the second diaphragm plate  323  is located within a cavity formed by the diaphragm  321  and the second diaphragm cap  312 . The pressure regulating device comprises a spring  331  and a regulating rod  332 , the spring  331  is located inside of the first diaphragm cap  311 , the regulating rod  332  comprises a third end  3321  and a fourth end  3322 , the third end  3321  of the regulating rod penetrates through the first diaphragm cap  311  and is in contact with the spring  331 , the fourth end  3322  of the regulating rod is suspended and the regulating rod is fixed on the first diaphragm cap  311 . 
         [0043]    The first diaphragm plate  322  further has effects of supporting the spring  331  and transferring spring force. The second diaphragm plate  323  further has an effect of isolating the outlet pressure and the exterior. 
         [0044]    Specifically, the first end  111  of the valve rod penetrates through the diaphragm  321  and is fixed on the first diaphragm plate  322 . The fixing piece  14  is fixed on the second diaphragm cap  312 . The fixing piece  14  can be integrally molded with the second diaphragm cap  312  and can also be fixed on the second diaphragm cap  312  as an independent part. As shown in  FIG. 4 , the fixing piece  14  is integrally molded with the second diaphragm cap  312 . It is to be noted that the fixing piece  14  is not limited to be fixed on the second diaphragm cap  312  and can be fixed with the actuator or the valve body as long as the essence of the present invention is satisfied. 
         [0045]    In order to enable the valve rod to move along a straight line to achieve a guide effect, the pressure regulating valve in this embodiment further comprises guide sleeves  17 , the guide sleeves  17  are fixed on the second diaphragm cap  312 , the guide sleeves  17  are rings which surround a cross section of the valve rod, and the number of the guide rings as shown in  FIG. 3  is two. Of course, the number of the guide rings can also be one or more; if a guide surface in contact with the valve rod  11  is smooth enough, there may be no guide ring.  FIG. 6  shows a balancing valve spool without a guide sleeve. The guide sleeves  17  can be made of brass, PTFE, etc. The guide sleeves  17  have an effect of guiding the valve rod  11  and also have an effect of reducing friction. 
         [0046]    Alternatively, the guide sleeves  17  can also be located on an outer circumference of the valve rod  11  (instead of the second diaphragm cap of the actuator) and are approximately located on the outer circumference of a middle position of the valve rod, which refers to a position between the first end  111  of the valve rod and the piston sleeve  12 . 
         [0047]    During manufacturing, the valve rod  11  and the piston sleeve  12  can be two independent parts and can also be integrally molded. In case of two independent parts, in order to isolate the inlet pressure and the outlet pressure, a second sealing part  16  is arranged at a connection between the valve rod  11  and the bottom portion  122  of the piston sleeve to achieve a sealing effect. The second sealing part  16  can be an O-ring and can also be sealing packing, etc. It is to be noted that the seal described here is a static seal as the fixing piece  14  and the piston sleeve  12  are relatively static. The purpose of isolating the inlet pressure and the outlet pressure is to enable the pressure regulating valve to maintain stable outlet pressure. However, the inlet pressure is certainly higher than the outlet pressure. If the inlet pressure and the outlet pressure are not isolated, the outlet pressure will always rise. 
         [0048]    It is to be noted that the main effect of the piston sleeve is to bear an upward balancing force to balance downward pressure produced by the gas inlet pressure (or liquid inlet pressure) to the valve seat. Therefore, other piston sleeve structures can be used as long as the essence of the present invention is satisfied, and the piston sleeve structures are not limited to that as shown in  FIG. 3  and  FIG. 4 . For example, in order to facilitate manufacturing in the process, the bottom portion  122  of the piston sleeve can also comprise an extending portion  123  which extends outwards along the axis direction of the valve rod and the extending portion  123  is closely fixed on the valve rod  11 , as shown in  FIG. 5  and  FIG. 6 . 
         [0049]    The second diaphragm cap  312  of the actuator and the valve body  2  are fixedly connected through screws as shown in  FIG. 4 , and other fixed connecting manners can also be adopted. If a contact part between the second diaphragm cap  312  and the valve body  2  is not well sealed, a third sealing part  4  can be arranged at the contact position to isolate medium in the valve body and the external environment, so as to achieve a sealing effect. The third sealing part can be an O-ring and can also be sealing packing, etc. 
         [0050]    By adopting the design in the above-mentioned embodiment, the structure of the existing pressure regulating valve (mainly the balancing valve spool) is simplified, the number of parts is reduced, the cost is reduced and the additional space does not need to be added in the longitudinal direction for the guide sleeves of the valve rod. 
         [0051]    As shown in  FIG. 4 , the working principle of the above-mentioned pressure regulating valve is that gas or liquid enters the valve along the first area from the inlet, inlet pressure acts on the valve seat to produce downward pressure, and the effect of the balancing valve spool is to produce an upward force to balance the downward pressure, wherein the bottom portion of the piston sleeve has an effect of bearing the upward pressure. A user can set the needed outlet pressure by regulating the spring force through the regulating rod as desired. Under the effect of the spring force, the valve rod will be enabled to move up and down and the valve seat moves up and down between the second area and the valve port. When the valve seat moves to the bottommost end, the opening of the valve port is the maximum and the outlet pressure of the second area becomes smaller; and when the valve seat moves up, the opening of the valve port becomes smaller, and the outlet pressure of the second area becomes larger; the valve rod does not stop moving until the outlet pressure reaches a needed value, and finally the pressure regulating valve is in a balanced state. 
         [0052]    At the beginning of the design of the balancing valve spool product, the force produced by the inlet pressure to the valve seat can be changed by changing the contact area of the bottom portion of the piston sleeve with the gas inlet pressure (or liquid inlet pressure) according to the actual needs, so as to satisfy the actual needs. At the beginning of the design of the pressure regulating valve product, the most suitable diaphragm size can be found by adjusting the size of the diaphragm to output the needed outlet pressure according to the actual needs. 
         [0053]    It is to be noted that the term “comprise”, “comprising” or any other variants in this disclosure intends to cover nonexclusive inclusion, so as to enable a process, method, object or equipment comprising a series of elements to not only comprise such elements, but also further comprise other elements which are not clearly listed, or further comprise intrinsic elements of such process, method, object or equipment. Under the situation of no more limitations, an element defined by a statement “comprising one . . . ” does not exclude the situation that other same elements also exist in the process, method, object or equipment comprising such elements. 
         [0054]    Although terms “first”, “second”, “third” and the like are used to describe various components, parts or portions, such components, parts or portions shall not be limited by such terms; and such terms can only be used for distinguishing a component, part or portion. When terms such as “first” and “second” and other numerical terms are used herein, it does not include sequence or order, unless otherwise clearly stated in the context. Therefore, under the situation of not departing from the illustration of the exemplary embodiments, the first component, part or portion below can be interpreted as a term “first element, part or portion”. 
         [0055]    The embodiments described above are just preferred embodiments of the present invention and are not used for limiting the protection range of the present invention. Any modification, equivalent replacement, improvement and the like made within the spirit and the principle of the present invention shall be included in the protection range of the present invention.