Abstract:
Disclosed is a piston device, comprising a piston body and a baffle plate of which the surface is provided with openings, wherein the baffle plate is arranged in the piston body and divides the piston body into an upper first area C and a lower second area B. Further disclosed is a pressure regulator which comprises the piston device. The piston device is beneficial for improving the stress balance of the first area and the second area, thereby improving the stability of the overall system.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a piston device and a pressure regulator using the same. 
       BACKGROUND ART 
       [0002]    In a pressure regulator, a piston device is used for controlling and regulating pressure of an outlet by a manner that one end of the piston device is connected with and driven by a valve rod. A valve port  300  is arranged between an inlet  100  and the outlet  200 , one end of the valve rod  110  is connected with the piston device  120 , and the valve rod  110  drives the piston device  120  to move up and down to control the opening and closing of the valve port  300  so as to adjust the pressure of the outlet  200 . 
         [0003]    Usually, an engineer arranges a perforated baffle plate  130  at the top of the piston device, a medium coming from the inlet  100  can flows into the piston device via the baffle plate  130 , thus the pressure on the baffle plate  130  is equal to the pressure of the lower surface of the baffle plate, but such design is only based on the hypothesis of a static medium. Once the medium flows, the medium enters a lower part area B of the baffle plate  130  via an upper part area A of the baffle plate  130 , and the flow speed of the medium at the upper part area A of the baffle plate  130  is obviously larger than that of the medium at the lower part area B of the baffle plate  130 . Therefore, the fluid flow state of the area A is very unstable, which results in that the baffle plate  130  is subjected to an unstable force, and the supplying stability of the medium at a downstream outlet  200  is influenced. Furthermore, as a lower cavity of the baffle plate is closed, the flow speed of the medium inside is very low, and as the speed is in inverse proportion to the pressure, namely, the pressure is small if the speed is high and the pressure is large if the speed is low, the pressure under the baffle plate  130  is larger than the pressure on the baffle plate  130 , the stresses of the upper and lower parts of the piston device are unbalanced and the downstream supplying stability is influenced as well. 
       SUMMARY OF THE INVENTION 
       [0004]    The invention provides a piston device, which can improve the stress conditions on and under a baffle plate of the piston device and improve the stability of the whole system when a fluid medium flows via the piston device. 
         [0005]    Specific technology embodiments of the invention provide a piston device, comprising a piston body and a baffle plate of which the surface is provided with openings, wherein the baffle plate is arranged in the piston body, and divides the piston body into an upper first area and a lower second area. 
         [0006]    The distance between the baffle plate and the upper end part of the piston body is larger than or equal to 3 mm. 
         [0007]    The distance between the baffle plate and the upper end part of the piston body is 4-35 mm. 
         [0008]    The distance between the baffle plate and the upper end part of the piston body is 5, 10, 15, 20, 25 or 30 mm. 
         [0009]    The piston body is also provided with a closing element, and the distance between the baffle plate and the upper end part of the piston body refers to the distance between the baffle plate and the closing element. 
         [0010]    The closing element is a cutting edge, rubber part or metal end surface. 
         [0011]    A positioning sleeve is arranged outside the piston body, and seal rings are arranged between the positioning sleeve and the piston body. The seal rings are O-shaped, Y-shaped or starlike. 
         [0012]    A guide belt is further arranged between the positioning sleeve and the piston body, and the piston body and the baffle plate are in integral or split design. 
         [0013]    The piston body and the baffle plate are installed via thread. 
         [0014]    According to the piston device provided by the specific technology embodiments of the invention, the baffle plate is arranged in the piston body and divides the piston body into the first area and the second area at upper and lower positions respectively, so the fluid medium flowing via the piston device can enter the first area of the piston and enter the second area via the perforated baffle plate, and the fluid medium is buffered in the first area, so that the fluid medium is balanced between the first area and the second area. Similarly, the piston device provided by the embodiments of the invention is also suitable for gas mediums. 
         [0015]    Furthermore, the inventor finds that when the distance between the baffle plate and the upper end part of the piston body is larger than or equal to 3 mm, the system performance of the whole piston device tends to be stable. Particularly, when the distance between the baffle plate and the upper end part of the piston body is equal to 4, 5, 10, 15, 20, 25 and 30 mm, the system performance is the best. The piston body is also provided with a closing element to help to realize a better sealing effect between the piston device and a valve port. 
         [0016]    The distance between the baffle plate and the upper end part of the piston body refers to the distance between the baffle plate and the closing element. 
         [0017]    When the closing element is a cutting edge, the distance between the baffle plate and the upper end part of the piston body refers to the distance between the baffle plate and the cutting edge. When the closing element is a rubber part, the distance between the baffle plate and the upper end part of the piston body refers to the distance between the baffle plate and the rubber part. When the closing element is a metal end surface, the distance between the baffle plate and the upper end part of the piston body refers to the distance between the baffle plate and the metal end surface. 
         [0018]    Furthermore, the positioning sleeve is arranged outside the piston body, so the piston device can be tightly wrapped, and does not generate radial displacement during movement up and down. 
         [0019]    Furthermore, the seal rings are arranged between the positioning sleeve and the piston body, when the piston device contacts with the valve port, a pressure regulator using the piston device is closed, and at the moment, the seal rings between the positioning sleeve and the piston body achieve a sealing effect, and prevent the medium from the inlet from entering the outlet side. 
         [0020]    Furthermore, the guide belt is arranged between the positioning sleeve and the piston body. The piston device is further wrapped in the positioning sleeve, and the guide belt further achieves the effect of guiding and lubricating the piston body. 
         [0021]    The piston body and the baffle plate can be in split connection and are convenient to detach and the piston body and the baffle plate can be installed via thread. The piston body and the baffle plate can be in integral design. 
         [0022]    In another aspect, the specific technology embodiments of the invention also provide a pressure regulator, comprising any abovementioned piston device as well as an inlet, an outlet, a valve port and a valve rod; the valve port is arranged between the inlet and the outlet, one end of the valve rod is connected with the piston device, and the valve rod drives the piston device to move up and down to control the opening and closing of the valve port, and control the pressure of the medium, which enters from the inlet, flowing out of the outlet. 
         [0023]    Sealing rubber, a cutting edge or metal end surface is arranged at one surface of the valve port opposite to the piston device. 
         [0024]    One end of the valve rod is in threaded connection with the baffle plate. 
         [0025]    Besides advantages of the piston device, the pressure regulator provided by the invention also has the advantage of stable performance. In order to achieve a better sealing effect, when the closing element of the piston device is the cutting edge or metal end surface, one surface of the valve port opposite to the piston device is provided with the sealing rubber. When the closing element of the piston device is the sealing rubber, one surface of the valve port opposite to the piston device is provided with the cutting edge or metal end surface. When the closing element of the piston device is the metal end surface, the valve port is provided with the metal end surface or sealing rubber corresponding to the metal end surface. In sum, due to the matching design of the cutting edge or metal end surface and the sealing rubber, the cutting edge or metal end surface can be cut into the sealing rubber, thus further achieving a better sealing effect. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a structural schematic diagram of a piston device used in a pressure regulator of the prior art. 
           [0027]      FIG. 2  is a structural schematic diagram of an embodiment of a piston device provided by the invention. 
           [0028]      FIG. 3  is a structural schematic diagram of an embodiment of a pressure regulator provided by the invention. 
           [0029]      FIG. 4  is a schematic diagram of ratio of the height to diameter of a baffle plate of the embodiment of the piston device provided by the invention. 
           [0030]      FIG. 5  is one schematic diagram of system pressure detection of the embodiment of the piston device in the embodiment of the pressure regulator provided by the invention. 
           [0031]      FIG. 6  is another schematic diagram of system pressure detection of the embodiment of the piston device in the embodiment of the pressure regulator provided by the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0032]    The technical scheme of the invention will be further described in detail in combination with the drawings and specific embodiments. 
       Embodiment I 
       [0033]    The invention provides an embodiment of a piston device, as shown in  FIG. 2 , the piston device comprises a piston body  220  and a baffle plate  230  of which the surface is provided with openings. The baffle plate  230  is arranged in the piston body  220  and divides the piston body into an upper first area C and a lower second area B. Thus when a flowing medium enters the piston body, is buffered by the first area C and enters the second area B, at the moment, due to the certain space of the first area C, the flow speed difference of the flowing medium in the first area C and the second area B is reduced, the pressure difference between the first area C and the second area B is reduced, the input and output pressure of the fluid medium flowing through the piston device is stabilized and the stability of the fluid medium is improved. 
         [0034]    The inventor furthers finds that when the distance between the baffle plate and the upper end part of the piston body is larger than or equal to 3 mm, namely, the height of the first area C is larger than or equal to 3 mm, and the relation between the input and output pressure of the fluid medium flowing through the piston device tends to be stable. When we select 4-35 mm as the distance between the baffle plate and the upper end part of the piston body, the relation between the input and output pressure of the fluid medium flowing through the piston device is more stable. When the distance between the baffle plate and the upper end part of the piston body is 5, 10, 15, 20 or 25 mm, the whole system is the most stable. A closing element is arranged at the upper part of the piston body, and is matched with a valve port outside the piston device for use. The closing element can be a cutting edge  280  or metal end surface, such that the valve port is provided with sealing rubber matched with the cutting edge or metal end surface. The cutting edge  280  or metal end surface can be directly cut into the sealing rubber to further enhance the sealing effect. The closing element can also be a rubber part, and the valve port is provided with a cutting edge or metal end surface matched with the rubber part. When the closing element is a metal end surface, the valve port is also provided with a metal end surface corresponding to and matched with the metal end surface for use. The distance between the baffle plate and the upper end part of the piston body refers to the distance between the baffle plate and the closing element. 
         [0035]    In addition, in order to further fix the piston device and improve the stability of the piston device, a positioning sleeve  270  can be arranged outside the piston body  220 . The positioning sleeve  270  can tightly wrap the piston device, so that the piston device does not generate radial displacement when moving up and down. The piston body and the baffle plate can be in split connection for being convenient to detach, and can also be in integral design, so as to ensure the stability of the system. 
         [0036]    Seal rings  240  and  250  are respectively arranged between the positioning sleeve  270  and the piston body  220 , when the piston device contacts with the outer valve port, the seal rings  240  and  250  can prevent inlet pressure from entering the outlet side, and the seal rings are O-shaped, Y-shaped or starlike. 
         [0037]    In addition, a guide belt  260  is arranged between the positioning sleeve and the piston body. The piston device is further wrapped in the positioning sleeve, thus guiding and lubricating effects are achieved. 
         [0038]    Embodiment II 
         [0039]    The invention provides an embodiment of a pressure regulator, comprising the embodiment of the piston device provided by the Embodiment I, which is not repeated herein.  FIG. 3  illustrates one embodiment of the pressure regulator, which further comprises an inlet  400 , an outlet  500 , a valve port  600  and a valve rod  310 , the valve port  600  is arranged between the inlet  400  and the outlet  500 , and a third area A is formed between the valve port  600  and the outlet  500 . One end of the valve rod  310  is connected to the piston device, the valve rod  310  drives the piston device to move up and down to control the opening and closing of the valve port  600 , and control the pressure of a medium, which enters from the inlet  400 , flowing out of the outlet  500 . One end of the valve rod  310  is in threaded connection with the baffle plate  330 , so the pressure regulator is convenient to be detached. 
         [0040]    When the piston device is away from the valve port  600 , the fluid medium flows via the third area A from the inlet  400 , flows out from the outlet  500 , and simultaneously enters the first area C and the second area B of the piston device, and through buffering of the first area C and the second area B, pressures of the upper and lower parts of the piston device tend to be consistent, and the unbalanced pressure of the upper and lower parts of the piston device is reduced. The pressure of the fluid medium flowing out the outlet  500  tends to be stable. 
         [0041]    When the height of the first area C or the distance between the baffle plate and the upper end part of the piston body comes up to a certain value, the pressure in the whole pressure regulator tends to be stable. The supplying pressure of the medium at the downstream outlet  500  tends to be stable. 
         [0042]    The embodiment of the pressure regulator provided by the invention further comprises sealing rubber  390  arranged on the valve port  600 , the piston device is provided with a cutting edge  380 , when the piston device gets close to the valve port, the cutting edge  380  is cut into the sealing rubber  390  to enhance airtightness of the piston and the valve port. As replacement of specific structures of the valve port and the closing element, when the closing element is sealing rubber, the valve port is provided with a cutting edge or metal end surface. 
         [0043]    In order to further describe technical effects of the invention, system pressure detection data of the embodiment of the pressure regulator are listed as follows: 
         [0044]      FIG. 4  is a schematic diagram of ratio of the height to diameter of the baffle plate of the embodiment of the piston device provided by the invention, wherein F is the diameter of the piston device and E is the distance between the baffle plate and the upper end part of the piston device. When the piston device is also provided with the closing element  401 , E is the distance between the baffle plate and the closing element  401 . 
         [0045]      FIG. 5  is one schematic diagram of system pressure detection of the embodiment of the piston device in the embodiment of the pressure regulator provided by the invention, we select 50 mm as the diameter of the piston device, the pressure of the inlet  400  is 30 bar, the pressure of the outlet  500  is controlled at 2.5 bar, through data analysis, we can see from  FIG. 5  that when the distance between the baffle plate and the upper end part of the piston device is larger than 3 mm and smaller than 38 mm, the whole system pressure tends to be a stable state. When the distance is 4 mm-31 mm, the upper and lower fluctuation of a system pressure curve is the most stable. When the distance is 10 mm±2 mm, 15 mm and 27 mm±2 mm, the system pressure curve is consistent. 
         [0046]      FIG. 6  is another schematic diagram of system pressure detection of the embodiment of the piston device in the embodiment of the pressure regulator provided by the invention, we select 50 mm as the diameter of the piston device, the pressure of the inlet  400  is 3 bar, the pressure of the outlet  500  is controlled at 2.5 bar, through data analysis, we can see from  FIG. 6  that when the distance between the baffle plate and the upper end part of the piston device is larger than 3 mm and smaller than 38 mm, the whole system pressure tends to be a stable state, and when the distance is 4, 5, 10, 15, 20, 25, 30 and 35 mm, the pressure curve is stable. 
         [0047]    When the piston device gets close to the valve port  600 , the fluid medium can enter the first area C and the second area B of the piston device from the inlet  400 , and pressures of the inlet  400 , the piston device and the sleeve can be relieved as well and the system burden of the whole pressure regulator is reduced. 
         [0048]    The pressure regulator provided by the invention also has the advantages of the embodiment of the piston device provided by the Embodiment I. Wherein, no matter the piston device is close to or away from the valve port, the seal rings  340  and  350  can seal the medium in the first area C and the second area B, and the medium cannot flow to the downstream outlet  500 . The seal rings are O-shaped, Y-shaped or starlike. 
         [0049]    The pressure regulator provided by the invention can regulate both liquid mediums and gas mediums. 
         [0050]    It is to be noted that in this article, terms “comprising” “containing” or any other variants mean to cover non-exclusive containing, so that the process, method, object or equipment including a series of elements not only comprises said elements, but also comprises other elements having not been expressly listed herein, or comprises those inherent to such process, method, object or equipment. Under the condition of no more limitations, the element defined by a phrase “comprising one . . . ” does not exclude that there are other same elements are existed in the process, method, object or equipment including said elements. 
         [0051]    Those described above are only preferable embodiments of the invention and are not intended to define the protection scope of the invention. Any modification, equivalent substitution, improvement and the like made in the spirit and principle of the invention are contained in the protection scope of the invention.