Regulating valve for ultrahigh pressure polyethylene device

Abstract

The utility model relates to a regulating valve for an ultrahigh-pressure polyethylene device, which comprises a filler assembly, a main sealing filler group, an inner auxiliary sealing filler group and an outer auxiliary sealing filler group, the main sealing packing set is provided with inverted-V-shaped supporting rings and PTFE sealing rings which are alternately arranged. A first cavity is formed between the supporting ring and the teflon sealing ring; the inner auxiliary sealing packing group is provided with a C-shaped ring with a downward opening; the outer auxiliary sealing filler set is provided with an upper filler, a plurality of middle fillers which are overlapped and are in an inverted V shape are arranged between the lower filler and the upper filler, and a second cavity is formed between the middle fillers. When the main sealing filler is extruded by a high-pressure medium, the inner wall face and the outer wall face of the teflon sealing ring are opened outwards, and the inclined faces are fully extruded to achieve ultrahigh-pressure environment sealing.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of governing valve, specifically a governing valve for superhigh pressure polyethylene device. BACKGROUND

[0002] High pressure polyethylene, also known as low density polyethylene (LDPE), is a thermoplastic plastic polymerized from ethylene. It is obtained by free radical polymerization under high temperature and high pressure conditions.

[0003] The high pressure polyethylene device is the main production device for producing high pressure ethylene, and the device is characterized by superhigh pressure working condition and extremely violent reaction. The valve used on the device generally works in a superhigh pressure environment of 260-320 MPa, so once the valve leaks, a serious safety accident is likely to occur.

[0004] Chinese patent CN209180488U discloses a high temperature and high pressure governing valve packing gland sealing assembly, wherein the packing body includes inverted V-shaped packing, and the inverted V-shaped packing includes fluorine-filled inverted V-shaped packing and metal inverted V-shaped packing; the fluorine-filled inverted V-shaped packing and the metal inverted V-shaped packing are arranged at intervals. The fluorine-filled packing is wrapped by the metal packing layer and will not stick together due to high temperature, so as to improve the high temperature resistance of the packing body.

[0005] When the governing valve is used in the high pressure polyethylene device, the extrusion force of the connection between the packing and the inner and outer sides thereof will be small due to the relatively high pressure of the medium, so that leakage is likely to occur.

[0006] Therefore, how to overcome the above defects has become a problem to be solved by those skilled in the art. INVENTION CONTENTS

[0007] To solve the technical problems in the background art, the utility model discloses a governing valve for superhigh pressure polyethylene device.

[0008] The utility model provides a governing valve for superhigh pressure polyethylene device, including valve body and valve rod, valve body and valve rod realize sealing through packing assembly between, packing assembly includes main sealing packing group, inner vice sealing packing group and outer vice sealing packing group that connect gradually,

[0009] The lower end of the main sealing packing group is provided with a packing bottom ring, and the upper end is provided with a packing top ring. A support ring and a fluorine sealing ring are arranged alternately and in an inverted V shape between the packing bottom ring and the packing top ring. A first cavity is formed between the support ring and the fluorine sealing ring.

[0010] The lower end of the inner vice sealing packing group is provided with a C-shaped ring with an opening facing downward. The upper end of the C-shaped ring is connected with a T-shaped combined sealing ring for sealing.

[0011] The lower end of the outer secondary sealing packing group is provided with a lower packing, the upper end is provided with an upper packing, and a plurality of intermediate packings in a reverse V shape are arranged between the lower packing and the upper packing, and the intermediate packings form a second cavity.

[0012] The beneficial effects of the above arrangement are: 1. Under the extrusion of high-pressure medium, the two walls of the fluorine sealing ring will open outward, the lower end surface groove of the support ring will form a limiting protection surface to prevent the fluorine sealing ring from cracking in the middle part due to excessive expansion, causing sealing failure; the upper end surface slope of the support ring will extrude the fluorine sealing ring groove, so that the inner and outer walls of the fluorine sealing ring open outward, and the slope fully extrudes to realize the sealing of the ultrahigh-pressure environment; 2. When the main sealing packing leaks, the ultrahigh-pressure medium will fill into the inner cavity of the metal C-shaped ring, so that its two wings are opened and tightly attached to the valve body and valve stem to realize sealing, and at the same time, the medium pressure makes it move upward to extrude the T-shaped combined sealing ring to realize sealing; 3. When the high-pressure medium flows to the outer secondary sealing packing group, the intermediate packing is extruded and deformed to realize the third sealing performance; 4. If the main sealing packing group has sealing performance, the high-pressure medium will not reach the inner secondary sealing packing group and the outer secondary sealing packing group, so the friction force at this position is very small, and the excessive packing will not cause the friction force of the valve stem to increase, affecting the operation of the valve.

[0013] The specific structure of the first cavity is that the upper end surface of the packing bottom ring and the lower end surface of the packing top ring are in a reverse V shape; the packing bottom ring and the packing top ring are connected with the support ring; and the included angle of the upper end surface of the support ring is greater than the included angle of the lower end surface of the fluorine sealing ring, thereby forming the first cavity.

[0014] If the inner secondary sealing packing group is directly connected with the main sealing packing group, since they are both flexible materials, direct connection will result in low connection strength, thereby reducing the sealing performance. Based on this, the further improvement is that the upper end of the main sealing packing group is provided with a packing gland; and the inner secondary sealing packing group and the outer secondary sealing packing group are arranged on the inner and outer sides of the packing gland.

[0015] The specific structure of the T-shaped combined sealing ring is that it comprises a first sealing ring, a second sealing ring and a third sealing ring connected in sequence; the first sealing ring is in a reverse T shape; the third sealing ring is provided with a downward-opening insertion slot; the second sealing ring is arranged at the bottom of the insertion slot; and the upper end of the first sealing ring abuts against the second sealing ring. In this way, the pressure of the first sealing ring on the second sealing ring is concentrated, there is no pressure loss, and the sealing performance of the third sealing ring can be improved; and the medium leaked from the metal C-shaped ring will make the two wings of the third sealing ring tightly attached to the sealing cavity, further improving the sealing effect.

[0016] Due to the small contact area of the first sealing ring and the second sealing ring, the side arm of the third sealing ring is difficult to expand, and based on this, the further improvement is that the U-shaped elastic sheet with the opening downward is arranged in the slot; the bottom of the elastic sheet abuts against the second sealing ring, and the side wall abuts against the slot wall; the upper end of the first sealing ring is inserted into the elastic sheet and abuts against the bottom of the elastic sheet.

[0017] The specific structure of the second cavity is that the included angle of the upper end face of the intermediate filler is larger than the included angle of the lower end face, so that the second cavity is formed between the intermediate fillers.

[0018] Further, the inner wall of the valve body is provided with a positioning table; the main sealing filler group and the positioning table are sequentially connected with a pressure reduction bottom ring and a guide sleeve; the inner and outer walls of the pressure reduction bottom ring are provided with a plurality of annular pressure reduction grooves arranged at intervals, for medium pressure reduction. The high-pressure differential medium flows on the inner and outer sides of the pressure reduction bottom ring to play a multi-stage pressure reduction role, relieve the damage caused by high flow rate of the medium, scrape off foreign matters adhered to the valve stem, play a cleaning role, and prevent impurities from entering the filler sealing assembly to cause sealing failure.

[0019] Due to the relatively large impact on the valve stem, the conventional valve stem is prone to wear, and based on this, the further improvement is that a surfacing layer is arranged at the connection position of the valve stem and the filler assembly, the surfacing material is tungsten carbide gold powder, the surface hardness is greater than or equal to 1000HV, and the roughness of this position is greater than or equal to Ra0.4.

[0020] The guide sleeve is used for guiding the movement of the valve stem; in order to prevent the filler sealing system from failing due to the vibration of the valve core rod caused by the flow of the high-pressure differential medium, the guide sleeve is configured to have a hardness smaller than that of the connection position of the valve stem and the filler assembly and have wear resistance.

[0021] The beneficial effects of the utility model are: 1. under the extrusion of high-pressure medium, the two wall surfaces of the fluorine sealing ring will open outward, the lower end surface groove of the supporting ring will form a limiting protection surface, preventing the fluorine sealing ring from cracking from the middle part due to excessive expansion, so as to cause sealing failure; the upper end surface slope of the supporting ring will extrude the fluorine sealing ring groove, so that the inner and outer wall surfaces of the fluorine sealing ring open outward, and the slope fully extrudes to realize the sealing of the ultrahigh pressure environment; 2. when the main sealing filler leaks, the ultrahigh pressure medium will fill into the inner cavity of the metal C-shaped ring, so that the two wings are opened and tightly attached to the valve body and the valve stem to realize sealing, and the medium pressure makes it move upward to extrude the T-shaped combined sealing ring, realizing sealing; 3. when the high-pressure medium flows to the outer secondary sealing filler group, the intermediate filler is extruded and deformed to realize the third sealing performance; 4. if the main sealing filler group has sealing performance, the high-pressure medium will not reach the inner secondary sealing filler group and the outer secondary sealing filler group, so the friction force at this position is very small, and the valve stem will not be affected by the high friction force caused by excessive filler, and the valve operation will not be affected. BRIEF DESCRIPTION OF DRAWINGS

[0022] The utility model is further illustrated below in combination with the drawings and examples.

[0023] Figure 1 It is the main view of the utility model;

[0024] Figure 2 It is the main view of the main sealing packing group;

[0025] Figure 3 It is the structure diagram before the four fluorine sealing ring opens;

[0026] Figure 4 It is the structure diagram after the four fluorine sealing ring opens;

[0027] Figure 5 It is the main view of the inner auxiliary sealing packing group and the outer auxiliary sealing packing group;

[0028] Figure 6 It is Figure 5 The enlarged view of A in the middle;

[0029] Figure 7 It is the main view of the pressure reduction bottom ring;

[0030] Figure 8 It is the main view of the valve stem;

[0031] In the drawing: 1, valve body; 2, valve stem; 3, main sealing packing group; 4, inner auxiliary sealing packing group; 5, outer auxiliary sealing packing group; 6, packing gland; 7, elastic sheet; 8, pressure reduction bottom ring; 9, guide sleeve; 10, anti-crack O-shaped ring; 11, guide composite bushing; 12, auxiliary sealing packing pressure ring; 13, packing pressing plate; 101, positioning platform; 21, hardfacing layer; 31, packing bottom ring; 32, packing top ring; 33, support ring; 34, four fluorine sealing ring; 35, first cavity; 41, C-shaped ring; 42, first sealing ring; 43, second sealing ring; 44, third sealing ring; 45, insertion slot; 51, lower packing; 52, upper packing; 53, intermediate packing; 54, second cavity; 81, pressure reduction groove. DETAILED DESCRIPTION

[0032] The utility model will be further explained in detail in combination with the drawings. These drawings are all simplified schematic diagrams, and only illustrate the basic structure of the utility model in a schematic manner, so it only shows the structure related to the utility model.

[0033] As Figure 1 shown, the utility model discloses a kind of regulating valve for superhigh pressure polyethylene device, including valve body 1 and valve stem 2, and sealing is realized between valve body 1 and valve stem 2 by packing assembly.Valve body 1 inner wall is provided with the positioning platform 101 towards up, positioning platform 101 is clamped with guide sleeve 9, for the valve stem 2 mobile guide.Guide sleeve 9 upper end is connected with the pressure reduction bottom ring 8 of sleeve joint valve stem 2, as shown inFigure 7 As shown, the inner and outer walls of the pressure reducing bottom ring 8 are provided with a plurality of annular pressure reducing grooves 81 arranged at intervals, for reducing the pressure of the medium. The high-pressure differential medium flows on the inner and outer sides of the pressure reducing bottom ring 8 to play a role of multi-stage pressure reduction, relieving the damage problem caused by high flow rate of the medium; at the same time, foreign matters adhered to the valve stem 2 can be scraped off, playing a cleaning role to prevent impurities and foreign matters from entering the packing seal assembly to cause seal failure.

[0034] The upper end of the valve body 1 is provided with a secondary sealing packing ring 12, and between the pressure reducing bottom ring 8 and the secondary sealing packing ring 12, along the flow direction of the medium, are sequentially connected a primary sealing packing group 3, an inner secondary sealing packing group 4 and an outer secondary sealing packing group 5, which constitute a packing assembly. The upper end of the secondary sealing packing ring 12 is connected with a packing pressing plate 13 fixed to the valve body 1 by bolts, and the packing pressing plate 13 exerts pressure on the secondary sealing packing ring 12, so that the primary sealing packing group 3, the inner secondary sealing packing group 4 and the outer secondary sealing packing group 5 are fixed.

[0035] The inner side surface of the secondary sealing packing ring 12 is clamped with a guide composite bushing 11, which can be a copper bearing or a plastic bearing, to prevent the secondary sealing packing ring 12 from scratching the valve stem.

[0036] The upper end of the outer secondary sealing packing group 5 and the lower end of the secondary sealing packing ring 12 are connected with a packing gland 6, the outer diameter of the packing gland 6 is smaller than the inner diameter of the valve body 1, and the inner diameter of the packing gland 6 is larger than the diameter of the valve stem 2, so that a filling cavity is formed between the packing gland 6 and the inner wall of the valve body 1 and between the packing gland 6 and the valve stem 2, and the inner secondary sealing packing group 4 and the outer secondary sealing packing group 5 are arranged in the filling cavity on the inner and outer sides of the packing gland 6. The reason for designing the packing gland 6 is that if the inner secondary sealing packing group 4 is directly connected with the primary sealing packing, the connection strength will be low due to the fact that both are flexible materials, thereby reducing the sealing performance.

[0037] The inner and outer sides of the packing gland 6 are clamped with anti-cracking O-rings 10, which are in sealing connection with the inner wall of the valve body 1 and the valve stem 2.

[0038] As Figure 2As shown, the lower end of the main sealing packing group 3 is provided with a packing bottom ring 31, and the upper end is provided with a packing top ring 32. The packing bottom ring 31 and the packing top ring 32 are provided with support rings 33 and PTFE sealing rings 34 arranged alternately and in inverted V shape. The included angle of the upper end surface of the support ring 33 is greater than the included angle of the lower end surface of the PTFE sealing ring 34, so that the first cavity 35 is formed between the support ring 33 and the PTFE sealing ring 34. In the embodiment, the lower end surface of the packing top ring 32, the upper end surface of the packing bottom ring 31 and the upper and lower end surfaces of the support ring 33 are all processed into grooves with an angle of 90°, so that the packing parts can be completely fitted between the inclined surfaces during extrusion, and the Ampco 22 or similar metal material is prevented from being damaged due to the extrusion deformation of the high-pressure medium. The upper end surface of the PTFE sealing ring 34 is designed as an inclined surface with an angle of 90°, and the lower end surface is designed as a groove with an angle of 75°. The angle difference between the upper and lower end surfaces is 7.5°. The purpose is that the PTFE sealing ring 34 can be easily deformed and tightly attached to the inner and outer wall surfaces during extrusion, so as to achieve sealing. The sealing principle is as follows: Figure 3 and Figure 4 As shown, under the extrusion of the high-pressure medium, the two wall surfaces of the PTFE sealing ring 34 are opened outward, the 90°-angle groove of the lower end surface of the support ring 33 forms a limiting protection surface, which prevents the PTFE sealing ring 34 from being excessively expanded and causing the middle part to crack, so as to cause sealing failure; the 90°-angle inclined surface of the upper end surface of the support ring 33 extrudes the 75°-angle groove of the PTFE sealing ring 34, so that the inner and outer wall surfaces of the PTFE sealing ring 34 are opened outward, and the inclined surface is fully extruded to achieve ultra-high pressure environment sealing.

[0039] As shown in Figure 5 and Figure 6 The lower end of the inner auxiliary sealing packing group 4 is provided with a C-shaped ring 41 with the opening downward; the upper end of the C-shaped ring 41 is connected with a T-shaped combined sealing ring for sealing. The T-shaped combined sealing ring comprises a first sealing ring 42, a second sealing ring 43 and a third sealing ring 44 connected in sequence; the first sealing ring 42 is in inverted T shape; the third sealing ring 44 is provided with a slot 45 with the opening downward; the second sealing ring 43 is arranged at the bottom of the slot 45; and the upper end of the first sealing ring 42 abuts against the second sealing ring 43. In this way, the pressure of the first sealing ring 42 on the second sealing ring 43 is concentrated, without pressure loss, so as to improve the sealing performance of the third sealing ring 44; and the medium leaked from the metal C-shaped ring 41 can make the two wings of the third sealing ring 44 tightly attached to the sealing cavity, further improving the sealing effect. Since the contact area of the first sealing ring 42 and the second sealing ring 43 is small, the side arm of the third sealing ring 44 is difficult to expand, so a U-shaped elastic piece 7 with the opening downward is installed in the slot 45; the bottom of the elastic piece 7 abuts against the second sealing ring 43, and the side wall abuts against the groove wall of the slot 45; and the upper end of the first sealing ring 42 is inserted into the elastic piece 7 and abuts against the bottom of the elastic piece 7.

[0040] As shown in Figure 5 and Figure 6As shown, the lower end of the outer secondary sealing packing group 5 is provided with a lower packing 51, the upper end is provided with an upper packing 52, and a plurality of intermediate packings 53 in a reverse V shape are arranged between the lower packing 51 and the upper packing 52, the included angle of the upper end surface of the intermediate packing 53 is greater than that of the lower end surface, so that the second cavities 54 are formed between the intermediate packings 53.

[0041] As shown in the drawings, Figure 8 As shown, the connection between the valve stem 2 and the packing assembly is provided with a surfacing layer 21, the surfacing material of which is tungsten carbide gold powder, so that the surface hardness is greater than or equal to 1000HV, the roughness at this position is greater than or equal to Ra0.4, and the surfacing layer 21 can be used only after the flaw detection confirms that there is no small crack.

[0042] Compared with the prior art, the beneficial effects of the embodiment are: 1. Under the extrusion of the high-pressure medium, the two walls of the PTFE sealing ring 34 will open outward, the lower end surface groove of the support ring 33 will form a limiting protection surface to prevent the PTFE sealing ring 34 from cracking from the middle part due to excessive expansion, so as to cause sealing failure; the upper end surface bevel of the support ring 33 will extrude the groove of the PTFE sealing ring 34, so that the inner and outer walls of the PTFE sealing ring 34 open outward, and the bevel fully extrudes to realize the sealing of the ultrahigh-pressure environment; 2. When the main sealing packing leaks, the ultrahigh-pressure medium will fill the inner cavity of the metal C-shaped ring 41, so that the two wings of the metal C-shaped ring 41 are opened and tightly attached to the valve body 1 and the valve stem 2 to realize sealing, and the medium pressure makes the metal C-shaped ring 41 move upward and extrude the T-shaped combined sealing ring; the medium leaking from the metal C-shaped ring 41 also makes the two wings of the T-shaped combined sealing ring tightly attached to the sealing cavity, which has sealing performance; the strong force of the ultrahigh-pressure medium on the metal C-shaped ring 41 makes the intermediate packing 53 extrude and deform to realize the third sealing performance; the anti-cracking and anti-explosion O-shaped ring 10 installed at the packing pressing ring is a guarantee for realizing the micro-leakage of the medium, so as to realize the high sealing performance; 4. If the main sealing packing group 3 has sealing performance, the high-pressure medium will not reach the inner secondary sealing packing group 4 and the outer secondary sealing packing group 5, so the friction force at this position is small, and the excessive packing will not cause the friction force of the valve stem 2 to increase, which affects the operation of the valve.

[0043] Based on the above ideal embodiments according to the utility model, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the utility model. The technical scope of the utility model is not limited to the content in the specification, and the technical scope must be determined according to the scope of claims.

Claims

1. A regulating valve for an ultra-high pressure polyethylene device, comprising a valve body (1) and a valve stem (2), wherein the valve body (1) and the valve stem (2) are sealed by a packing assembly, characterized in that: The packing assembly includes a main sealing packing group (3), an inner secondary sealing packing group (4), and an outer secondary sealing packing group (5) connected in sequence; The main sealing packing assembly (3) has a packing bottom ring (31) at its lower end and a packing top ring (32) at its upper end. An alternately arranged, inverted V-shaped support ring (33) and a PTFE sealing ring (34) are provided between the packing bottom ring (31) and the packing top ring (32). The support ring (33) and the PTFE sealing ring (34) form a first cavity (35). The lower end of the inner auxiliary sealing packing assembly (4) is provided with a C-shaped ring (41) with the opening facing downward; the upper end of the C-shaped ring (41) is connected with a T-shaped combined sealing ring for sealing; The lower end of the external auxiliary sealing packing group (5) is provided with a lower packing (51) and the upper end is provided with an upper packing (52). Multiple stacked intermediate packings (53) in an inverted V shape are provided between the lower packing (51) and the upper packing (52), and the intermediate packings (53) form a second cavity (54).

2. The regulating valve for an ultra-high pressure polyethylene device according to claim 1, characterized in that: The upper end face of the bottom packing ring (31) and the lower end face of the top packing ring (32) are both inverted V-shaped; The bottom packing ring (31) and the top packing ring (32) are both connected to the support ring (33); The included angle of the upper end face of the support ring (33) is greater than the included angle of the lower end face of the PTFE sealing ring (34), thereby forming the first cavity (35).

3. The regulating valve for an ultra-high pressure polyethylene device according to claim 1, characterized in that: The upper end of the main sealing packing assembly (3) is provided with a packing gland (6); The inner auxiliary sealing packing group (4) and the outer auxiliary sealing packing group (5) are both provided on the inner and outer sides of the packing gland (6).

4. The regulating valve for an ultra-high pressure polyethylene device according to claim 1, characterized in that: The T-shaped combined sealing ring includes a first sealing ring (42), a second sealing ring (43), and a third sealing ring (44) connected in sequence; The first sealing ring (42) is inverted T-shaped; The third sealing ring (44) is provided with a slot (45) with the opening facing downward; The second sealing ring (43) is disposed at the bottom of the slot (45); The upper end of the first sealing ring (42) abuts against the second sealing ring (43).

5. A regulating valve for an ultra-high pressure polyethylene device according to claim 4, characterized in that: A U-shaped spring piece (7) with its opening facing downwards is installed in the slot (45); The bottom of the spring piece (7) abuts against the second sealing ring (43), and the side wall abuts against the groove wall of the slot (45); The upper end of the first sealing ring (42) is inserted into the spring piece (7) and abuts against the bottom of the spring piece (7).

6. A regulating valve for an ultra-high pressure polyethylene device according to claim 1, characterized in that: The included angle of the upper end face of the intermediate filler (53) is greater than the included angle of the lower end face, so that the intermediate filler (53) forms a second cavity (54).

7. A regulating valve for an ultra-high pressure polyethylene device according to claim 1, characterized in that: The valve body (1) is provided with a positioning platform (101) on its inner wall; The main sealing packing assembly (3) and the positioning platform (101) are connected in sequence by a pressure-reducing bottom ring (8) and a guide sleeve (9); The inner and outer walls of the pressure-reducing bottom ring (8) are provided with multiple spaced, annular pressure-reducing grooves (81) for medium pressure reduction.

8. A regulating valve for an ultra-high pressure polyethylene device according to claim 7, characterized in that: The valve stem (2) is provided with a weld overlay layer (21) at the connection between the valve stem (2) and the packing assembly. The weld overlay material is tungsten carbide gold powder, which makes its surface hardness ≥1000HV and its roughness Ra0.4 or higher.

9. A regulating valve for an ultra-high pressure polyethylene device according to claim 8, characterized in that: The guide sleeve (9) is used to guide the movement of the valve stem (2); The guide sleeve (9) is configured such that its hardness is less than that of the valve stem (2) at the connection packing assembly, and it has wear resistance.

Images