Seal pair and piston unit

Abstract

The present application relates to the technical field of mechanical seal, and provides a sealing pair and a piston unit, the sealing pair comprising: a flexible sealing ring provided with a first groove; and a metal sealing ring, part of the metal sealing ring being arranged in the first groove, and the metal sealing ring being provided with a second groove with the same opening direction as the first groove. The present application has the characteristics of simple structure, good sealing performance, wide application range, and convenient maintenance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical seal, in particular to a sealing pair and a piston unit. BACKGROUND

[0002] Since the piston unit is often used in the cavity of the hydraulic cylinder or the stop valve, in order to prevent the leakage of the liquid, the gap between the piston unit and the cavity needs to be sealed.

[0003] In the related art, the commonly used sealing method is to set a conventional sealing ring, but the sealing effect is not ideal. SUMMARY

[0004] The present application provides a sealing pair and a piston unit, which can effectively improve the sealing performance, has the characteristics of simple structure, wide application range, easy maintenance and the like.

[0005] The present application provides a sealing pair, comprising: a flexible sealing ring, provided with a first groove; a metal sealing ring, part of the metal sealing ring is arranged in the first groove, and the metal sealing ring is provided with a second groove with the same opening direction as the first groove.

[0006] According to the sealing pair provided by the present application, the inner wall of the first groove is provided with a metal spring.

[0007] According to the sealing pair provided by the present application, the maximum width of the cross section of the flexible sealing ring is not less than the maximum width of the cross section of the metal sealing ring.

[0008] According to the sealing pair provided by the present application, the flexible sealing ring is a U-shaped sealing ring, and the metal sealing ring is a C-shaped sealing ring.

[0009] According to the sealing pair provided by the present application, two groups of the sealing pair are used to be coaxially arranged on the two ends of the outer wall of the piston.

[0010] According to the sealing pair provided by the present application, two groups of the sealing pair are used to be reversely arranged on the two ends of the outer wall of the piston.

[0011] The present application also provides a piston unit, comprising a piston and the above-mentioned sealing pair, and the sealing pair is arranged on the outer wall of the piston.

[0012] According to the piston unit provided by the present application, the outer wall of the piston is provided with a stop ring at each end, and the sealing pair is arranged between the stop rings.

[0013] According to the piston unit provided by the present application, the outer wall of the piston is provided with an oil seal.

[0014] According to the piston unit provided by the present application, the sealing pair is provided with multiple groups.

[0015] The sealing pair and the sealing unit provided by the application can realize two-stage progressive deformation sealing at a sealing gap simultaneously, have the characteristics of simple structure, wide application range and convenient maintenance, etc.

[0016] Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following description and drawings or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the application or the related art, the following will briefly introduce the drawings needed to be used in the embodiments or the related art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0018] Figure 1 is one of the structural schematic diagrams of the high-temperature and high-pressure resistant cut-off sealing device provided by the application;

[0019] Figure 2 is the partial enlarged view of A of Figure 1

[0020] Figure 3 is the structural schematic diagram of the primary cut-off valve provided by the application;

[0021] Figure 4 is the second structural schematic diagram of the high-temperature and high-pressure resistant cut-off sealing device provided by the application;

[0022] Figure 5 is the partial assembly diagram of the cut-off mechanism provided by the application;

[0023] Figure 6 is one of the structural schematic diagrams of the holding slip provided by the application;

[0024] Figure 7 is the second structural schematic diagram of the holding slip provided by the application;

[0025] Figure 8 is the structural schematic diagram of the piston unit from one perspective provided by the application;

[0026] Figure 9 ​is a structure schematic view of the piston unit from another perspective provided by the present application;

[0027] Figure 10 is a sectional view of the piston unit provided by the present application;

[0028] Figure 11 is a structure schematic view of the sealing pair provided by the present application;

[0029] Reference signs:

[0030] 1: stirring shaft; 2: valve body; 3: clamping assembly; 301: driving rod;

[0031] 302: piston unit; 303: clamping slip; 4: joint; 5: first step portion;

[0032] 6: annular sealing groove; 7: first sealing element; 8: elastic element; 9: first gland;

[0033] 10: second step portion; 11: first annular compression pad; 12: positioning pad;

[0034] 13: first locking nut; 14: second sealing element; 15: second gland;

[0035] 16: accommodating portion; 17: second annular compression pad; 18: second locking nut;

[0036] 19: first guide ring; 20: second guide ring; 21: third gland;

[0037] 22: flexible sealing body; 23: buckle; 24: clamping jaw; 25: clamping cavity;

[0038] 26: bayonet; 27: notch; 28: clamping petal; 29: bearing cover;

[0039] 30: first clamping groove; 31: clamping portion; 32: clamping groove; 33: second clamping groove;

[0040] 34: metal baffle; 35: clamping opening; 36: pin; 37: piston;

[0041] 38: flexible sealing ring; 39: metal sealing ring; 40: first groove;

[0042] 41: second groove; 42: metal elastic sheet; 43: compression ring; 44: blocking ring; 45: oil seal. DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and advantages of the present application clearer, the following will clearly and completely describe the technical solutions in the present application with reference to the drawings in the present application. Obviously, the described embodiments are only a part of embodiments of the present application, but not all embodiments of the present application. Based upon the embodiments in the present application, all other embodiments obtained by those ordinarily skilled in the art without creative efforts should fall into the scope of the present application.

[0044] In the description of the embodiments of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0045] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those ordinarily skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0046] In the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0047] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0048] The high-temperature and high-pressure resistant cut-off sealing device of the present application will be described below in conjunction with the drawings. It should be understood that the parts of the entire device of the present application can be made of conventional high-temperature and high-pressure resistant materials to adapt to high-temperature and high-pressure working conditions, and of course can also be used for normal temperature and pressure working conditions.

[0049] According to an embodiment of the present application, as shown in Figures 1-11 The high-temperature and high-pressure resistant cut-off sealing device provided by the present application can be sealed and assembled on the outside, generally the top, of a reaction kettle, a storage tank or the like, and mainly comprises a cut-off valve and a sealing mechanism. The cut-off valve can realize static sealing when the stirring shaft 1 stops working, so as to maintain temperature and pressure and facilitate other debugging, maintenance and the like of the equipment. The sealing mechanism can realize dynamic sealing when the stirring shaft 1 works, and of course can also realize static sealing when the stirring shaft 1 stops working.

[0050] According to an embodiment of the present application, the cut-off valve comprises a valve body 2 and a cut-off mechanism. The valve body 2 is provided with a first channel and a second channel intersecting and communicating with each other. The valve body 2 is adapted to be sleeved on the stirring shaft 1 through the first channel. The upper and lower ends of the stirring shaft 1 respectively penetrate the first channel. The upper end of the stirring shaft 1 is connected with a driving motor. The lower end of the stirring shaft 1 extends into a reaction kettle, a storage tank or the like. In this example, the first channel and the second channel are arranged perpendicular to each other. The first channel is vertically arranged, and the second channel is horizontally arranged.

[0051] According to the embodiment of the present application, the cutting-off mechanism is sealed in the second channel, and the cutting-off mechanism comprises two embracing components 3 which are identical in structure and oppositely arranged, and the two embracing components 3 are oppositely arranged on the left and right sides of the stirring shaft 1 in the radial direction to embrace and seal or release the stirring shaft 1. Specifically, when the device needs to be debugged, maintained or the like, the stirring shaft 1 stops working, and the two embracing components 3 move oppositely to embrace the stirring shaft 1, so as to realize the cutting-off static sealing, to keep the temperature and pressure, and to prevent the high-temperature and high-pressure liquid from leaking out; when the device is debugged and maintained, the two embracing components 3 move away from the stirring shaft 1 to release the stirring shaft 1, and the stirring shaft 1 can resume working, and at this time, other sealing members on the stirring shaft 1 can be used for sealing, such as the commonly used sealing ring or the sealing mechanism of the present application.

[0052] According to the embodiment of the present application, as shown in Figure 1 The cutting-off valve further comprises a connector 4 which is sleeved on the stirring shaft 1, the lower end of the first channel is provided with a first step portion 5, the upper portion of the connector 4 is arranged in the inside of the lower end of the first channel by means of thread connection or the like and abuts against the first step portion 5, the lower portion of the connector 4 extends to the outside of the lower end of the first channel, and the bottom of the connector 4 is provided with an annular sealing groove 6 for installing a sealing ring, and the annular sealing groove 6 is spaced apart from the stirring shaft 1. The connector 4 can be used to seal and install the cutting-off valve to the top of the device, and the annular sealing groove 6 is arranged to be spaced apart from the stirring shaft 1, so that the stirring shaft 1 cannot wear the sealing ring in the annular sealing groove 6, and at this time, it is static sealing, which can effectively improve the sealing performance and service life of the sealing ring and achieve a good sealing effect. When the high-temperature and high-pressure liquid in the device spreads upward along the gap between the stirring shaft 1 and the connector 4, the sealing can be realized by the cutting-off valve or the sealing mechanism.

[0053] In some embodiments, a sealing ring is arranged between the connector 4 of the cutting-off valve and the stirring shaft 1, so that when the stirring shaft 1 resumes working and the cutting-off valve is opened, the sealing can be realized by the sealing ring.

[0054] In some embodiments, the connector 4 of the cutting-off valve is an eccentric connector, so that the connector 4 can be conveniently aligned and installed with the device.

[0055] It can be understood that the number of the cutting-off mechanism of the cutting-off valve of the present application is not particularly limited, and in general, the more the number is, the better the cutting-off sealing effect is, and the number can be designed according to the actual working condition and the assembly space. For example, Figure 1 and Figure 3 The cutting-off mechanism and the second channel are respectively arranged as one, to constitute a one-stage cutting-off valve, Figure 4The two cut-off mechanisms and the second channel are correspondingly arranged respectively, to form a two-stage cut-off valve, and similarly, a multi-stage cut-off valve can be formed, and the corresponding overall device is a one-stage high-temperature and high-pressure resistant cut-off sealing device, a two-stage high-temperature and high-pressure resistant cut-off sealing device and a multi-stage high-temperature and high-pressure resistant cut-off sealing device.

[0056] When the sealing mechanism is arranged in the cut-off valve, the first channel of the valve body 2 comprises an upper end portion and a lower end portion, and when the cut-off valve is used alone, i.e., without the sealing mechanism, the first channel of the valve body 2 can comprise only the lower end portion for the mounting joint 4.

[0057] According to an embodiment of the present application, as shown in Figure 1 and Figure 4 The sealing mechanism comprises a first sealing assembly, the first sealing assembly comprises a first sealing member 7, an elastic member 8 and a first gland 9, the first sealing member 7 is arranged between the upper end inner wall of the first channel and the stirring shaft 1, the upper end bottom of the first channel is provided with a second step portion 10, the elastic member 8 is sleeved on the stirring shaft 1 and located below the first sealing member 7, i.e., the elastic member 8 is arranged between the second step portion 10 and the first sealing member 7, for giving the first sealing member 7 a pre-tightening force; the first gland 9 is sleeved on the stirring shaft 1, and the first gland 9 is connected to the upper end outer wall of the first channel of the valve body 2 by thread connection or the like, for pressing the first sealing member 7 and the elastic member 8 in the upper end interior of the first channel. During assembly, the first gland 9 presses the first sealing member 7 downward, and compresses the elastic member 8, converting the axial pressure into a radial force, the first sealing member 7 deforms and opens radially, achieving a pre-interference sealing effect, and achieving a static sealing effect. In the working state, as the first sealing member 7 wears, the elastic member 8 will give the first sealing member 7 a continuous compensation force, so that the first sealing member 7 is always in a balanced force working state, and opens radially, thereby achieving a dynamic sealing effect. Therefore, the sealing mechanism has the characteristics of long service life and no need for frequent replacement.

[0058] In some embodiments, as shown in Figure 1 , a first annular pressing pad 11 is arranged between the first gland 9 and the first sealing member 7, and the first annular pressing pad 11 is sleeved on the stirring shaft 1, so that the first sealing member 7 can be pressed better.

[0059] In some embodiments, the elastic member 8 can be a spring, and a positioning pad 12 is arranged between the elastic member 8 and the first sealing member 7, for positioning the elastic member 8.

[0060] In some embodiments, the upper end outer wall of the first channel of the valve body 2 is provided with an external thread, and the upper end outer wall of the first channel is sleeved with a first locking nut 13, when the first gland 9 is screwed downward, the first locking nut 13 is screwed upward, and when the two abut, the first gland 9 is locked.

[0061] According to the embodiment of the present application, the sealing mechanism further comprises a secondary sealing assembly, the secondary sealing assembly comprises a second sealing element 14 and a second gland 15, the upper end of the first gland 9 is integrally formed with a receiving portion 16, the second sealing element 14 is arranged between the receiving portion 16 and the stirring shaft 1; the second gland 15 is sleeved on the stirring shaft 1 and connected to the outer wall of the receiving portion 16 by thread connection or the like, for pressing the second sealing element 14 in the receiving portion 16. The secondary sealing assembly can further improve the sealing effect of the stirring shaft 1. It can be understood that the number of the secondary sealing assembly of the present application is not particularly limited, in general, the more the number is, the better the sealing effect is, which can be designed according to the actual working condition and the assembly space.

[0062] In some embodiments, a second annular compression pad 17 is arranged between the second gland 15 and the second sealing element 14, the second annular compression pad 17 is sleeved on the stirring shaft 1, and the second annular compression pad 17 is used to better press the second sealing element 14.

[0063] In some embodiments, the outer wall of the receiving portion 16 is provided with external threads, and the outer wall of the receiving portion 16 is sleeved with a second locking nut 18, when the second gland 15 is screwed downward, the second locking nut 18 is screwed upward, and when the two abut, the locking of the second gland 15 is realized.

[0064] In some embodiments, the first sealing element 7 and the second sealing element 14 of the present application can be commonly used rubber sealing rings resistant to high temperature and high pressure, and when arranged, a plurality of rubber sealing rings can be stacked in the upper end of the first passage of the valve body 2 and in the receiving portion 16, respectively, so that the sealing effect can be improved and frequent replacement can be avoided.

[0065] In some embodiments, the first sealing element 7 and the second sealing element 14 of the present application can also use the multi-stage sealing assembly in the patent document "CN201521138447.1, a super-high-pressure multi-stage sealing assembly".

[0066] In some embodiments, a first guide ring 19 is arranged between the second gland 15 and the stirring shaft 1, a second guide ring 20 is arranged between the bottom of the upper end of the first passage of the valve body 2 and the stirring shaft 1, and the second guide ring 20 is arranged between the elastic element 8 and the second stepped portion 10. The first guide ring 19 and the second guide ring 20 distributed above and below can realize the guiding and positioning of the stirring shaft 1.

[0067] In some embodiments, a third gland 21 is threadedly connected to the top of the second gland 15, which is convenient for mounting and pressing the first guide ring 19.

[0068] According to the embodiment of the present application, the high-temperature and high-pressure resistant cut-off sealing device can realize dynamic sealing when the stirring shaft 1 is working or static sealing when the stirring shaft 1 is stopped, when the elements (for example, the first sealing member 7 and the second sealing member 14) of the sealing mechanism are damaged, the stirring shaft 1 stops working, at this time, the two clamping assemblies 3 of the cut-off valve can clamp the stirring shaft 1, realizing the cut-off sealing of the high-temperature and high-pressure liquid, that is, static sealing, then the elements of the upper sealing mechanism can be replaced in the static sealing state, after the replacement is completed, the two clamping assemblies 3 of the lower cut-off valve are loosened, and then the stirring shaft 1 resumes normal work. Therefore, the high-temperature and high-pressure resistant cut-off sealing device can realize effective sealing of the stirring shaft 1, and when the elements of the sealing mechanism are damaged, the reaction kettle and other equipment do not need to be cooled and depressurized, but the elements of the sealing mechanism can be replaced in the sealed high-temperature and high-pressure state in a short time, which has the characteristics of convenient use, good sealing performance, easy maintenance and replacement and the like.

[0069] Next, the clamping assembly 3 provided by the present application will be described as follows, Figure 1 and Figure 5 The clamping assembly 3 of the embodiment of the present application comprises, from outside to inside, a driving rod 301, a piston unit 302 and a clamping slipper 303, the first end of the clamping slipper 303 is provided with a flexible sealing body 22 for sealing the stirring shaft 1, when the clamping slipper 303 clamps the stirring shaft 1, the flexible sealing body 22 is extruded, the flexible sealing body 22 is deformed to fill the gap, and sealing is realized; the first end of the piston unit 302 is connected with the second end of the clamping slipper 303, the driving end of the driving rod 301 is connected with the second end of the piston unit 302, the driving rod 301 can drive the piston unit 302 to slide radially, and then drive the clamping slipper 303 to slide radially in the second channel of the valve body 2, so as to clamp and seal the stirring shaft 1 or loosen the stirring shaft 1.

[0070] In some embodiments, the driving rod 301, the piston unit 302 and the clamping slipper 303 are connected in a split type, which is convenient for disassembly and maintenance.

[0071] In some embodiments, the driving rod 301, the piston unit 302 and the clamping slipper 303 are connected in a threaded connection.

[0072] In some embodiments, the driving rod 301, the piston unit 302 and the clamping slipper 303 are connected in a threaded connection.

[0073] Of course, in other embodiments, the driving rod 301, the piston unit 302 and the clamping slipper 303 can adopt a combination of threaded connection and clamping.

[0074] The specific material of the flexible sealing body 22 is not particularly limited, and for example, a modified polytetrafluoroethylene material can be used. The modified polytetrafluoroethylene material has the characteristics of wear resistance, high temperature and high pressure resistance, and good sealing performance. In addition, the flexible sealing body 22 has a slight creep at high temperatures, which greatly reduces the surface roughness requirement of the coupling part (for example, the stirring shaft 1), reduces the processing difficulty, and enhances the sealing performance.

[0075] In some embodiments, as shown in Figures 5-9 The second end of the clamping slip 303 is provided with a buckle 23, and the first end of the piston unit 302 is provided with a clamping jaw 24. The clamping jaw 24 is clamped with the buckle 23, so as to realize the clamping of the clamping slip 303 and the piston unit 302. The second end of the piston unit 302 is provided with a clamping chamber 25, and the driving end of the driving rod 301 is clamped in the clamping chamber 25 of the piston unit 302 through a clamping spring, so as to realize the clamping of the driving rod 301 and the piston unit 302. When the driving rod 301 drives the piston unit 302, the piston unit 302 is pushed to reciprocate. Compared with the rotating mode of the piston unit 302, the reciprocating mode of the present application can effectively protect the sealing pair of the piston unit 302 and prolong the service life of the sealing pair.

[0076] In some embodiments, the clamping slip 303 and the buckle 23 are threadedly connected, and of course, they can also be designed in one piece.

[0077] In some embodiments, the inner wall of the clamping chamber 25 is provided with an annular clamping opening 26. The clamping spring is sleeved on the driving end of the driving rod 301 and then extends into the clamping chamber 25 at the same time. The clamping spring is clamped into the clamping opening 26, so as to connect the driving end of the driving rod 301 in the clamping chamber 25.

[0078] In some embodiments, the side surface of the clamping jaw 24 is provided with a notch 27. The buckle 23 can be withdrawn from the notch 27 on the side surface, so as to separate from the clamping jaw 24, thereby facilitating the replacement of the clamping slip 303 or the piston unit 302.

[0079] In some embodiments, the clamping jaw 24 includes a plurality of annular clamping petals 28, and the adjacent clamping petals 28 have a spacing. The clamping jaw 24 is arranged in the form of the clamping petals 28, which can produce a certain elasticity. When the piston unit 302 is subjected to the thrust of the driving rod 301, the buckle 23 can be clamped into the clamping jaw 24 formed by the clamping petals 28, so as to realize the clamping. In addition, when the annular clamping petals 28 are cut to form the notch 27.

[0080] According to the embodiments of the present application, the two ends of the second channel of the valve body 2 are respectively fixed with bearing covers 29 through screws, so as to protect the elements such as the piston unit 302 and the clamping slip 303 in the second channel. The driving rod 301 extends into the second channel through the bearing cover 29, and the bearing cover 29 can also guide and position the driving rod 301.

[0081] In some embodiments, the driving rod 301 is screwed with the bearing cover 29, when the driving rod 301 is screwed in, the piston unit 302 does reciprocating motion but not rotating motion due to the clamping of the driving end of the driving rod 301 and the clamping cavity 25 of the piston unit 302.

[0082] In the related art, when the shaft sleeve or the stop valve is used to seal the shaft part such as the stirring shaft 1, a common sealing ring is usually arranged between the two, but the sealing effect is poor, the service life is short, and the sealing ring needs to be frequently replaced.

[0083] To solve the above technical problems, as shown in Figure 5 and Figure 6 The first end of the clamping slip 303 is provided with a first clamping groove 30 matched with the stirring shaft 1, in this example, the first clamping groove 30 is semicircular, and in use, the first clamping grooves 30 of the two clamping slips 303 can be combined into a circular shape to tightly hold the stirring shaft 1; and the inner wall of the first clamping groove 30 covers part of the flexible sealing body 22, so that another part of the flexible sealing body 22 is exposed outside the first clamping groove 30, and the two ends of the flexible sealing body 22 protrude from the first clamping groove 30 in the circumferential direction, so that when the two clamping slips 303 are matched, there is a gap between them, which is filled with the flexible sealing body 22, for providing a sealing compensation amount. Specifically, when the driving rod 301 or other driving device drives the clamping slip 303 to tightly seal, the clamping slip 303 extrudes the flexible sealing body 22, so that the exposed and protruding flexible sealing body 22 is extruded and deformed in the axial and radial directions, thereby continuously filling the surrounding gap, realizing deformation sealing of the stirring shaft 1 and the stop valve passage cavity where the stirring shaft 1 is located, and effectively improving the sealing effect.

[0084] The "coating" mentioned here can be understood as that the flexible sealing body 22 covers the entire inner wall of the clamping slip 303, the contact area of the two is the inner wall area of the clamping slip 303, which effectively improves the damage area, and when the flexible sealing body is damaged, the extrusion of the clamping slip 303 can continuously provide a sealing compensation amount within a certain period of time, thereby improving the service life of the flexible sealing body 22 as a whole and reducing the replacement frequency.

[0085] In some embodiments, the clamping slip 303 can realize effective sealing at a high temperature of 280-360℃.

[0086] As shown in Figure 6As shown, the inner wall of the first holding groove 30 of the holding slip 303 is provided with a clamping portion 31 in the circumferential direction, and the two sides of the flexible sealing body 22 are respectively provided with a clamping groove 32 matched with the clamping portion 31, so that the flexible sealing body 22 can be embedded in the holding slip 303, that is, the holding slip 303 of this embodiment can be called an embedded holding slip, which is convenient for disassembling and replacing the flexible sealing body 22; it can be understood that when the flexible sealing body 22 is embedded in the first holding groove 30, a shape matched with the first holding groove 30 can be formed.

[0087] In one embodiment, the flexible sealing body 22 is semi-ring-shaped matched with the first holding groove 30, and two semi-ring flexible sealing bodies can be combined into a flexible sealing ring. The flexible sealing ring structure adopted by the present application has the characteristics of good sealing effect, small extrusion force, and can be used in smaller assembly space.

[0088] In some embodiments, the thickness of the flexible sealing ring is 2-5 mm.

[0089] According to the embodiment of the present application, as shown in Figure 7 The present application also provides a holding slip 303, and the flexible sealing body 22 of each holding slip 303 is provided with a second holding groove 33 matched with the stirring shaft 1. In this example, the second holding groove 33 is semi-circular, and in use, the second holding grooves 33 of the two holding slips 303 can be combined into a circle to hold the stirring shaft 1; and the two opposite surfaces of each flexible sealing body 22 are respectively partially provided with a metal baffle 34, the metal baffle 34 is arranged adjacent to the second holding groove 33, and the metal baffle 34 is provided with a holding opening 35 matched with the second holding groove 33 on the inner side facing the stirring shaft 1, so that when the two holding slips 303 are held, the holding openings 35 can also be combined into a circle to hold the stirring shaft 1.

[0090] It should be understood that when the driving rod 301 or other driving device drives the holding slip 303 to hold the seal, the metal baffle 34 is forced to hold in the middle, at this time, the flexible sealing body 22 can be prevented from being excessively extruded upward and downward along the gap of the stirring shaft 1 through the metal baffle 34, thereby reducing the wear of the flexible sealing body 22 and improving its service life; and when the two ends of the holding slip 303 are subjected to inward extrusion force, the flexible sealing body 22 can be deformed by creeping towards the middle and all sealing surfaces, thereby achieving a continuous compensation sealing effect on the stirring shaft 1 and the passage cavity of the stop valve in which the stirring shaft 1 is located. That is, the holding slip 303 of this embodiment can be called a continuously compensating holding slip.

[0091] In some embodiments, the flexible sealing body 22 is in the shape of a block, specifically a square block, and compared with the flexible sealing ring of the above-mentioned embodiments, the thickness of the flexible sealing body 22 is effectively improved, which can be used for 3-4 years, further improving the wear resistance and service life and avoiding frequent replacement.

[0092] In some embodiments, the length (thickness), width and height of the flexible sealing body 22 are 20-40 mm, respectively.

[0093] In some embodiments, when the gripping slip 303 grips the sealing stirring shaft 1, the gap between the gripping opening of the metal baffle 34 and the stirring shaft 1 is 0.1-0.2 mm. Since there is a certain gap between the metal baffle 34 and the stirring shaft 1 when the stirring shaft 1 is gripped, if the gap is too large, the flexible sealing body 22 is prone to excessive extrusion, which causes great loss of the flexible sealing body 22. Therefore, by setting the gap to 0.1-0.2 mm, the extrusion loss of the flexible sealing body 22 can be effectively reduced, and the service life thereof is prolonged.

[0094] In some embodiments, a gap is provided between the side of the metal baffle 34 away from the gripping opening 35 and the gripping slip 303, and the gap is filled with the flexible sealing body 22. When the gripping slip 303 is gripped, the flexible sealing body 22 in the gap and the flexible sealing body 22 on the side can be peristaltically deformed, so as to achieve a continuous compensation sealing effect on the second passage of the valve body 2.

[0095] In some embodiments, the metal baffle 34 is fixed to the flexible sealing body 22 by the pin 36, and other fixing modes can also be adopted.

[0096] The specific material of the metal baffle 34 is not particularly limited, and for example, chromium-molybdenum alloy, stainless steel or the like can be adopted.

[0097] Since the piston unit 302 is often used in the cavity of a hydraulic cylinder or a stop valve, in order to prevent the leakage of the liquid, the gap between the piston unit 302 and the cavity needs to be sealed. In the related art, a conventional sealing ring is generally adopted for sealing, but the sealing effect is poor, especially under high temperature and high pressure conditions, the sealing effect is not ideal.

[0098] Please continue to refer to Figures 8-11 To solve the above technical problems, the piston unit 302 of the present application comprises a piston 37 and a sealing pair, the sealing pair is sleeved on the outer wall of the piston 37, that is, is arranged between the second passage of the valve body 2 and the piston 37, and is used for sealing the gap therebetween, so as to prevent the leakage of the high temperature and high pressure liquid through the second passage.

[0099] The sealing pair comprises a flexible sealing ring 38 and a metal sealing ring 39, the flexible sealing ring 38 is provided with a first groove 40; part of the metal sealing ring 39 is arranged in the first groove 40, and the metal sealing ring 39 is provided with a second groove 41 which has the same opening direction as the first groove 40. As shown in Figure 11As shown, when the second groove 41 of the metal sealing ring 39 is subjected to pressure of gas or liquid, the axial pressure is converted into radial pressure, the radial opening achieves the effect of deformation sealing, and at the same time, the flexible sealing ring 38 at the lower end is energized to open, achieving the effect of further deformation sealing, and since the lower end sealing adopts a flexible material resistant to high temperature and high pressure, the deformation amount is relatively larger than that of the metal sealing ring 39, and the sealing compensation effect on the second passage of the valve body 2 is better. Through the rigid-flexible combined sealing pair, the two-stage progressive deformation sealing can be realized at one sealing gap, and the sealing requirement under the working condition of 360 DEG high temperature and 40 MPa high pressure can be achieved. Compared with the related art, the sealing pair effectively improves the sealing performance.

[0100] In some embodiments, the inner wall of the first groove 40 of the flexible sealing ring 38 is provided with a metal spring 42, which is combined with the inner wall of the first groove 40, can give the flexible sealing ring 38 a pre-tightening force, so that it can tightly fit the inner cavity of the second passage of the valve body 2 under normal temperature and pressure, and achieve good sealing effect. Therefore, through the setting, the application range of the sealing pair is improved.

[0101] In some embodiments, the maximum width W1 of the cross section of the flexible sealing ring 38 is not less than the maximum width W2 of the cross section of the metal sealing ring 39, so that along the axial direction, the metal sealing ring 39 can be within the cladding range of the flexible sealing ring 38, and then the metal sealing ring 39 can better transmit the acting force to the flexible sealing ring 38, and further improve the sealing effect.

[0102] In one embodiment, the flexible sealing ring 38 is a U-shaped sealing ring, and the metal sealing ring 39 is a C-shaped sealing ring.

[0103] The specific materials of the flexible sealing ring 38, the metal sealing ring 39 and the metal spring 42 are not particularly limited, for example: the flexible sealing ring 38 can adopt a modified polytetrafluoroethylene material, and the metal sealing ring 39 and the metal spring 42 can adopt chromium-molybdenum alloy, stainless steel and the like.

[0104] In one embodiment, the piston unit 302 is provided with two groups of sealing pairs, and the two groups of sealing pairs of the above-mentioned embodiments can be coaxially sleeved on the outer wall of the piston 37 at both ends, that is, the openings of the first groove 40 of the flexible sealing ring 38 and the second groove 41 of the metal sealing ring 39 in the two groups of sealing pairs are all towards the upper side or the lower side, when assembled in the same direction, it belongs to a one-way high-temperature and high-pressure resistant combined sealing pair, and can achieve the effect of one-way sealing.

[0105] Of course, the two sets of sealing pairs can also be reversely sleeved on the outer wall of the piston 37, that is, the openings of the first grooves 40 of the flexible sealing rings 38 and the second grooves 41 of the metal sealing rings 39 in one set of sealing pairs face upward or downward, and the openings of the first grooves 40 of the flexible sealing rings 38 and the second grooves 41 of the metal sealing rings 39 in the other set of sealing pairs face downward or upward. It can be understood that when the two sets of sealing pairs are reversely assembled, the bidirectional high-temperature and high-pressure resistant combined sealing pairs can have a bidirectional sealing effect.

[0106] In addition, the specific number of the sealing pairs of the present application is not particularly limited, and in general, under the premise of not affecting the sliding of the piston unit, the sealing effect will be better with the increase of the number of the sealing pairs.

[0107] In some embodiments, the sealing pairs of the present application can also be arranged at each connection of the overall device of the present application to improve the overall sealing performance of the device.

[0108] In one embodiment, as shown in Figure 2 , the sealing pairs are arranged between the first gland 9 and the upper end of the first channel of the valve body 2 and are compressed by the compression ring 43 to prevent them from falling off.

[0109] In some embodiments, as shown in Figure 10 , the outer wall of the piston 37 is provided with a stop ring 44 at each end, and the sealing pairs are arranged between the two stop rings 44, which can prevent the sealing pairs from falling off.

[0110] In some embodiments, the outer wall of the piston 37 is provided with an oil seal 45, which is located between the two sets of sealing pairs to further improve the sealing effect.

[0111] In summary, the high-temperature and high-pressure resistant stop sealing device of the present application can be applied to the dynamic sealing and static sealing of various shaft parts, has the characteristics of convenient use, good sealing performance, and easy maintenance, etc.

[0112] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A seal pair, characterized in that The utility model relates to a sealing pair for a piston, comprising: a flexible sealing ring provided with a first groove; a metal sealing ring, a part of the metal sealing ring being arranged in the first groove, and the metal sealing ring being provided with a second groove facing the same direction as the first groove; the flexible sealing ring is a U-shaped sealing ring, and the metal sealing ring is a C-shaped sealing ring; an inner wall of the first groove is provided with a metal spring; the maximum width of the cross section of the flexible sealing ring is not less than the maximum width of the cross section of the metal sealing ring; when the second groove of the metal sealing ring is subjected to pressure of a liquid, axial pressure is converted into radial pressure, radial opening reaches the effect of deformation sealing, and the flexible sealing ring is simultaneously subjected to the effect, so that the flexible sealing ring is stored with energy and opened, further deformation sealing is achieved, and two-stage progressive deformation sealing is realized.

2. The seal pair of claim 1 wherein, two groups of the sealing pairs are used to be coaxially arranged at both ends of the outer wall of the piston.

3. The seal pair of claim 1 wherein, two groups of the sealing pairs are used to be oppositely arranged at both ends of the outer wall of the piston.

4. A piston unit characterized by, the sealing pair of any one of claims 1-3 is arranged on the outer wall of the piston.

5. The piston unit according to claim 4, characterized in that the outer wall of the piston is respectively provided with a retaining ring at both ends, and the sealing pair is arranged between the retaining rings.

6. The piston unit of claim 5, wherein, the outer wall of the piston is provided with an oil seal.

7. The piston unit of claim 5, wherein, the sealing pair is provided with multiple groups.

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