Overpressure valve for regulated discharge of overpressure of gas

Abstract

The invention relates to an overpressure valve for the regulated discharge of an overpressure of a gas, in particular CO2, from a refrigerant circuit of a vehicle, comprising:-a valve body (1) having a gas inlet (11) and a gas outlet (12) and a flow channel (13) connecting the gas inlet (11) and the gas outlet (12); a sealing piston (2) which is arranged in the flow channel (13) so as to be movable in particular along the axis of the valve body (1) relative to a sealing surface (14), which is arranged on the valve body (1) and which is in particular of conical design, and which has a conical piston sealing surface (21), the piston sealing surface abuts against the sealing surface (14) in the closed state and closes the flow channel (13); an adjusting bolt (4) for adjusting the opening pressure, the adjusting bolt in the valve body (1) being arranged downstream of the sealing piston (2) in the flow channel (13); and-a spring (3), in particular a compression spring, which is arranged between the sealing piston (2) and the adjusting bolt (4) and which applies a closing force to the sealing piston (2) in order to bear against the sealing surface (14); and wherein the sealing piston (2), the valve body (1) and the spring (3) are designed in such a way that, when a defined pressure level at the gas inlet (11) is exceeded, the sealing piston (2) is displaced against the spring (3) in the opening direction and releases a passage cross-section for the gas and can be returned from an open state into a closed state when below the pressure level, wherein the piston sealing surface (21) has a piston angle (a) between 26 DEG and 35 DEG, in particular 26.5 DEG and 28.5 DEG, and wherein the sealing surface (14) of the valve body (1) has a body angle (beta) between 27 DEG and 38 DEG, in particular 30 DEG and 31 DEG, and wherein the ratio of the body angle (beta) to the piston angle (a) is 15 / 14 < = beta / alpha < = 124 / 108.

Description

Technical Field

[0001] The invention relates to an overpressure valve for the controlled release of an overpressure of a gas from a refrigerant circuit according to the preamble of claim 1 . Background Art

[0002] A large number of overpressure valves are known from the prior art, which are used to discharge or reduce the pressure level of the gas exceeding the defined limit value from the fluid circuit. In the air-conditioning system with R744 (CO2) as a refrigerant in the automotive field, multiple overpressure valves are usually installed. The high-pressure overpressure valve or High Pressure Relief Valve (HPRV) is also directly installed on the compressor or compressor of the high-pressure circuit. Here, the high-pressure overpressure valve protects the system to prevent an impermissible high pressure exceeding 160±10 bar. These impermissible high pressures may occur in particular when the compressor or its regulating and control mechanism fails. In the low-pressure circuit, there is usually a low-pressure overpressure valve directly in the expansion valve. The low-pressure overpressure valve is used to protect the low-pressure circuit to prevent a pressure exceeding 120±10 bar. Because two expansion valve units are provided in the common system in the R744-air-conditioning system of the car, two low-pressure overpressure valves are also installed in most cases.

[0003] In the automotive sector, pressure relief valves are also known from the prior art in the area of ​​air conditioning, which discharge the gas, mostly CO2 (R744), which is a refrigerant and flows in the refrigerant circuit, from the refrigerant circuit when a defined pressure level is exceeded. Thus, for example, a pressure relief valve is known from the prior art, which consists of a sealing seat, a stainless steel ball as a sealing element, a pressure piece and a valve body and an associated pressure spring. Here, the ball is held in place by an intermediate piece. However, the intermediate piece limits the range of motion of the ball to a few tenths of a millimeter. The intermediate piece is cross-grooved on the front end that receives the ball all the way to the bearing surface of the spring, so that the outflowing medium can flow through these slots. The sealing ball is centered here with the help of a cone and thus seals the sealing seat.

[0004] From the prior art, for example, WO 2008129209 A1 is known. It discloses a sealing body having a hemispherical part that seals the sealing seat and a flat part on which a spring acts. In addition, overpressure valves are known from US 10180192 B2 and KR 102138568 B1, which have a very complex structure and whose operating principle is elaborately designed.

[0005] The disadvantage of the systems known from the prior art is that they are usually of complex construction and are therefore usually complex and expensive in construction and also in assembly. In addition, the systems known from the prior art, in particular with a ball as a sealing body, tend to tilt or close imprecisely when triggered, i.e. when a critical pressure is exceeded, or to engage in so-called chattering, i.e. a continuous opening and closing of the sealing body, which disadvantageously leads to fluctuations in the pressure level. Summary of the invention

[0006] It is therefore an object of the present invention to provide a pressure relief valve which ensures a simple construction and which reliably discharges the excess pressure from the air-conditioning system when the opening pressure is reached and which reliably prevents malfunctions.

[0007] This object is achieved with characteristic features in a pressure relief valve according to the preamble of claim 1. Therefore, according to the invention, it is provided that the piston sealing surface has a piston angle between 26° and 35°, in particular 26.5° to 28.5°, wherein the sealing surface of the valve body has a valve body angle of 27° to 38°, in particular 30° to 31°, wherein the ratio of valve body angle to piston angle is 15 / 14≤β / α≤124 / 108.

[0008] The angle difference according to the invention achieves a particularly good sealing function between the sealing surface of the valve body and the sealing surface of the piston. In addition, the different angles make it possible to achieve a high tightness even at high temperatures. Likewise, the angle according to the invention achieves a high tightness even when the pressure relief valve is triggered multiple times, or also achieves a constant opening pressure and flow rate after closing, so that the function of the pressure relief valve is maintained even when it is opened and closed multiple times.

[0009] In conjunction with the present invention, the angle between the piston sealing surface and the piston axis is referred to as the piston angle α. The angle of the valve body sealing surface relative to the valve body axis is correspondingly referred to as the valve body angle β.

[0010] The object according to the invention is also achieved by the characterizing features in a pressure relief valve according to the preamble of claim 2. According to the invention, it is provided that the sealing piston has a guide surface which is arranged downstream of the piston sealing surface in the axial direction of the sealing piston and on which the sealing piston is guided in the valve body, and

[0011] The piston sealing surface opens into an opening enlargement area formed in the sealing piston, which is arranged between the piston sealing surface and the guide surface, wherein the sealing piston has a larger projection area in the area of ​​the opening enlargement area when viewed in the opening direction than the projection area in the inlet.

[0012] The opening enlargement area ensures reliable opening of the pressure relief valve, so that when the set overpressure at the gas inlet is exceeded, the sealing piston is first slightly displaced in the direction of the opening, and then the pressure of the medium impinges on the opening enlargement surface, causing a large force counter to the spring and thus reliably ensuring the flow of gas through the pressure relief valve. Thus, the opening of the pressure relief valve is reliably ensured by the opening enlargement area, wherein vibration of the pressure relief valve, that is, a constant change between opening and closing, can be reliably prevented.

[0013] Particularly advantageous embodiments of the pressure relief valve are defined in detail by the features of the dependent claims:

[0014] In order to ensure a particularly advantageous flow of gas through the overpressure valve, it can be provided that the opening enlargement surface transforms into the guide surface, wherein a through-gap in the sealing piston is constructed in the transition area between the opening enlargement surface and the guide surface and / or in the guide surface, through which the gas flows in the open state into a gas collecting chamber arranged downstream of the sealing piston, and excess pressure flows into the gas collecting chamber in the open state of the sealing piston and can then escape into the surrounding environment through the gas collecting chamber via the flow channel, in particular via the adjusting screw and the gas outlet.

[0015] In the research that forms the basis of the present invention, it was surprisingly found that the ratio of the diameter of the sealing piston to the diameter of the valve body in the guide area has a positive influence on the closing characteristics and the sealing of the overpressure valve. Here, it is preferably provided that the ratio of the diameter of the sealing piston at the guide surface to the diameter of the valve body in the area of ​​the guide surface of the sealing piston is 291 / 290≤D1 / D2≤668 / 645, in particular 291 / 290≤D1 / D2≤148 / 145,

[0016] The diameter of the valve body at the guide surface is 6.52 mm≤D1≤6.68 mm, in particular 6.62 mm≤D1≤6.66 mm.

[0017] An advantageous construction of the overpressure valve is provided by the through-gap being constructed as a number, in particular four, of flattened portions which are evenly distributed over the circumference of the sealing piston, wherein in particular the through-gap is constructed in a stepped manner in the transition region between the opening enlargement region and the guide surface and in the guide surface.

[0018] Furthermore, if, in particular, the gas flows out of the gas collecting chamber in a defined manner via the adjusting screw, the closing behavior of the pressure relief valve is positively influenced. Preferably, provision is made here for the projected passage area A3 of the gas at the adjusting screw to be 0.7*Pimm 2 ≤A3≤1.01*Pi mm 2 , especially 0.74*Pi mm 2≤A3≤1.0041*Pi mm 2 .

[0019] Advantageously, provision is made here for the adjusting screw to be arranged in the valve body in the region of the gas outlet and to close the latter, wherein the adjusting screw has a number of through-holes which communicate with the flow channel, in particular a gas collecting chamber, and can escape from the gas collecting chamber into the surroundings due to pressure.

[0020] In order to be able to achieve high tightness of the pressure relief valve cost-effectively and easily even at relatively high temperatures, it can optionally be provided that the sealing piston is made of a thermoplastic, in particular PEEK or PEKEKK, and the valve body is made of metal, in particular an aluminum alloy or a steel alloy.

[0021] In order to limit the maximum displacement of the sealing piston in the opening direction, it can be provided according to the invention that the adjusting screw has a stop projection pointing in the direction of the sealing piston and / or the sealing piston has a stop projection pointing in the direction of the adjusting screw, wherein the stop projection limits the maximum displacement stroke in the opening direction of the sealing piston in such a way that the guide surface contacts the surface of the valve body opposite the guide surface when the pressure relief valve is fully opened. As a result, the stop projection can particularly easily prevent the sealing piston from slipping out of the guide surface, so that the function is particularly reliably and continuously ensured when the pressure relief valve is opened and closed multiple times, and tilting of the sealing piston in the valve body is advantageously prevented.

[0022] In the case of the pressure relief valves known from the prior art, the spring force decreases over time, in particular when used at elevated temperatures, and the opening pressure also drops significantly, in extreme cases even to below a limit value at which the pressure relief valve is triggered. In order to prevent this particularly effectively, it can advantageously be provided that the spring is installed in a prestressed state, so that when the operating temperature of the pressure relief valve is reached, in particular a maximum operating temperature between 100° C. and 200° C., preferably between 150° C. and 160° C., an optimum prestress of the spring is present, wherein the spring is installed in particular when preheated to the operating temperature. Alternatively, it has been found that when spring steel is used and the spring is installed in the pressure relief valve in its hot state, i.e., for example at operating temperature or higher, the required spring force is introduced at higher temperatures or the spring is prestressed and the spring force is maintained for a longer period of time.

[0023] Further advantages of the embodiments of the present invention are apparent from the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention is schematically shown in the drawings and described by way of example with reference to the drawings according to particularly advantageous embodiments which should not be construed as limiting:

[0025] Figure 1 shows a sectional view of a pressure relief valve according to the invention, Figure 2 The side view shows the Figure 1 Another cross-sectional view of the overpressure valve, Figure 3 shows a sectional view of the pressure relief valve according to the invention in the open position, Figure 4 shows a front view of the sealing piston, and Figure 5 Shows that according to Figure 4 Side view of the sealing piston. DETAILED DESCRIPTION

[0026] exist Figure 1 1 shows the pressure relief valve according to the invention in a sectional view along the axis of the valve body 1. The pressure relief valve comprises a valve body 1 in which a sealing piston 2 is arranged coaxially with the axis of the valve body 1. The valve body 1 has a gas inlet 11 and a gas outlet 12, wherein the gas inlet 11 and the gas outlet 12 are connected via a flow channel 13, so that gas, such as CO2, can enter the valve body 1 from the refrigerant circuit of the vehicle via the gas inlet 11 and pass through the valve body 1 via the gas outlet 12 or the flow channel 13 when the pressure relief valve is triggered and escape into the surrounding environment. The sealing piston 2 is arranged in the valve body 1 in the flow channel 13 relative to a sealing surface 14 arranged on the valve body 1. The sealing piston 2 has a conical piston sealing surface 21, which in the closed state of the pressure relief valve rests on the sealing surface 14 of the valve body 1 and thus seals or closes the flow channel 12. An adjusting screw 4 for adjusting the opening pressure is arranged in the region of the gas outlet 12 of the valve body 1. The adjusting screw 4 is arranged downstream of the sealing piston 2 in the flow channel 13 , and thus coaxially behind the sealing piston 2 in the flow direction of the gas from the gas inlet 11 to the gas outlet 12 with respect to the axis of the valve body 1 .

[0027] A spring 3 is arranged between the sealing piston 2 and the adjusting screw 4, and the spring is configured as a compression spring. The spring 3 applies pressure between the adjusting screw 4 and the sealing piston 2, so that the sealing piston 2 is pressed toward the sealing surface 14 of the valve body 1 with the piston sealing surface 21 in the closing direction, that is, in the direction of the gas inlet 11. If the adjusting screw 14 screwed into the valve body 1 with a thread is adjusted, the distance between the sealing body 2 and the adjusting screw 4 changes and the spring 3 is preloaded or the pressure acting on the sealing piston 2 is increased or reduced. Therefore, the opening pressure of the sealing piston 2 can be changed and the prestress of the spring 3, that is, the closing force, can be adjusted by means of the adjusting screw 4.

[0028] The piston sealing surface 21 is configured with a piston angle α of 27°, wherein the piston angle α is between the axis of the sealing piston 2 and the piston sealing surface 21. The sealing surface 14 of the valve body 1 has a valve body angle β of 30.5°, wherein the valve body angle β is between the axis of the valve body 1 and the sealing surface 14. The angle difference between the piston angle α of the piston sealing surface 21 and the valve body angle β of the sealing surface 14 is Figures 1 to 3 In the current embodiment, it is 3.5°. In the research that is the basis of the present invention, it has been advantageously confirmed that the piston angle α is advantageously between 26° (inclusive) and 35° (inclusive), preferably between 26.5° (inclusive) and 28.5° (inclusive), and the valve body angle β of the sealing surface 14 is between 27° (inclusive) and 38° (inclusive), particularly advantageously between 30° (inclusive) and 31° (inclusive). It has also been advantageously confirmed that the ratio of the valve body angle β to the piston angle α is advantageously 15 / 14≤β / α≤124 / 108. The angular difference between the piston angle α and the valve body angle β can advantageously be between 1.5° and 5°.

[0029] The sealing piston 2 has a guide surface 22 disposed along the axial direction of the sealing piston 2 in the direction of the gas outlet 12. The sealing piston 2 is guided in the guide surface 22 in the valve body 1 and slides along the guide surface 22 during opening and closing. The piston sealing surface 21 opens into an opening enlargement area 23 formed in the sealing piston 2, which is arranged between the piston sealing surface 21 and the guide surface 22. The opening enlargement area 23 is formed in the sealing piston 2. Figures 1 to 5 In the embodiment of the present invention, the opening enlargement area 23 is arranged downstream of the piston sealing surface 21 and is formed by a surface area extending parallel to the axis of the valve body 1, which then has a large angle and opens into the guide surface 22. When the pressure relief valve is opened, the opening enlargement area 23 serves to enlarge the pressure surface for the outflowing gas and to achieve a more reliable opening of the pressure relief valve when a defined pressure level is applied in the gas inlet 11. It has been found that a particularly advantageous intensification of the opening movement of the sealing piston 2 is achieved if the opening enlargement area 23 has a larger projected area in the opening direction of the sealing piston 2 than an end face 24 of the sealing piston 2 arranged in the gas inlet 11 of the flow channel 13.

[0030] An optional through-opening 25 is formed in the enlarged opening region 23 , which opens into the guide surface 22 and through which the gas can flow via the guide surface 22 or the enlarged opening region 23 itself into the rear gas collecting chamber 6 of the sealing piston 2 .

[0031] According to the following Figures 1 to 3 The function of the pressure relief valve according to the invention is described by way of example with reference to a preferred embodiment of the invention.

[0032] If the overpressure valve is arranged in the refrigerant circuit of the vehicle, the pressure guided in the refrigerant circuit acts on the end face 24 of the sealing piston 2. If the pressure in the refrigerant circuit exceeds the level set on the overpressure valve, the force on the end face 24 increases and exceeds the closing force of the spring 3 and the sealing piston 2 moves in the opening direction and opens the overpressure valve. If the overpressure valve is opened, the sealing piston 2 moves in the direction of the gas outlet 12 and the gas is discharged as in Figure 2 As shown in FIG. 2 , the gas flows into the opening enlargement area 23. In the opening enlargement area 23, the projection surface of the sealing piston 2 is enlarged, so that a stronger opening movement overcomes the closing force of the spring 3 and is applied to the sealing piston 12 in the direction of the gas outlet 12, and the sealing piston 2 is also displaced in the direction of the gas outlet 12 or the adjusting screw 4. By the movement of the sealing piston 2 inside the valve body 1, the gas can enter the gas collecting chamber 6 through the through-gap 25 and enter the gas collecting chamber 6 through the gas collecting chamber and the adjusting screw 4 along the Figure 3 The arrow shown in the figure flows out of the overpressure valve. A sealing film 27 is arranged at the end of the gas outlet 12 or the flow channel 13, which tears when the overpressure valve is opened for the first time and thus indicates the triggering of the overpressure. If the pressure in the refrigerant circuit drops below the limit value, the closing force of the spring 3 exceeds the pressure of the gas again and the spring 3 presses the sealing piston 2 in the direction of the gas inlet 11 again, whereby the piston sealing surface 21 contacts the sealing surface 14 of the valve body 1 and closes the overpressure valve again.

[0033] Figure 4 A preferred embodiment of the sealing piston 2 according to the invention is shown in a front view looking at the end face 24 of the sealing piston 2. In this embodiment, the sealing piston 2 has four through-holes 25, which are evenly distributed in the circumferential direction of the sealing piston 2. The through-holes 25 are arranged as shown in FIG. Figure 5 The configuration shown in the figure is a flattened portion and is arranged in the transition area between the opening enlargement area 23 and the guide surface 22 and in the guide surface 22. The through-gap 25 has a stepped configuration here and thus allows the gas to flow into the gas collecting chamber 6 via the opening enlargement area 23 and the guide surface 22.

[0034] In studies it has been found that the diameter D2 ( Figure 3 ) and valve body (1)( Figure 2) The ratio D1 / D2 of the diameter D1 in the guide surface 22 of the sealing piston 2 is 291 / 290 (inclusive) to 668 / 645 (inclusive). The diameter D1 of the valve body 1 at the guide surface 22 is advantageously 6.52 (inclusive) to 6.68 mm (inclusive), particularly preferably 6.62 (inclusive) to 6.66 mm (inclusive). The ratio D1 / D2 thus enables a particularly high sealing performance and positively influences the closing behavior, so that even in the case of temperature expansion, the sealing piston 2 does not become blocked or stuck in the valve body 1.

[0035] As in Figure 1 and 3 As shown in FIG. 1 , the adjusting screw 4 has a certain number of through-holes 41 in the area of ​​the gas outlet 12, which connect the gas collecting chamber 6 to the surrounding environment. The flow channel 13 is thus continued from the gas inlet 11 via the gas collecting chamber 6 through the through-holes 41 to the surrounding environment or the gas outlet 12, so that the gas can escape through the overpressure valve via the flow channel 13 of the overpressure valve. It has been found that the projected through-surface of the gas at the adjusting screw 4 is 0.7*Pi mm 2 To 1.01*Pi mm 2 (inclusive), particularly preferably 0.74*Pi mm 2 (inclusive) to 1.0041*Pi mm 2 This results in a particularly advantageous closing behavior, ie an advantageous pressure ratio between the gas in the gas collecting chamber 6 and the gas in the gas inlet 11 flowing into the pressure relief valve, so that a reliable closure or a reliable closing movement of the sealing piston 2 is achieved.

[0036] exist Figures 1 to 5 In the embodiment shown, the sealing piston 2 is made of the thermoplastic material PEKEKK and the valve body 1 is made of an aluminum alloy. Optionally, it can be provided that the sealing piston 2 can also be made of other thermoplastics, such as PEEK, and the valve body 1 can be made of other materials, such as a steel alloy.

[0037] exist Figures 1 to 5 In a preferred embodiment, the adjusting screw 4 has a stop projection 8 pointing in the direction of the sealing piston 2. The sealing piston 2 also has a stop projection 8 pointing in the direction of the adjusting screw 4, wherein the respective stop projection 8 limits the maximum displacement stroke of the sealing piston 2 in the opening direction, so that the two stop projections 8 abut against each other when there is a maximum opening degree. The stop projection 8 reliably ensures that the guide surface 22 contacts the surface of the valve body 1 opposite to the guide surface 22 when the overpressure valve is opened to the maximum extent, and thus advantageously prevents the sealing piston 2 from tilting in the valve body 1.

[0038] A preferred embodiment of the pressure relief valve according to the invention provides that the spring is installed in the valve body 1 of the pressure relief valve in a prestressed state. The spring 3 is preferably heated in a preheated state, that is, at a temperature corresponding to a maximum operating temperature of, for example, between 100° C. and 200° C., preferably between 150° C. and 160° C., and then installed in the pressure relief valve. The spring 3 is then in an optimal prestressed state in the installed state, resulting in a particularly high tightness of the pressure relief valve.

[0039] As in Figures 1 to 5 As an alternative to the stepped through-opening 25 shown in , the through-opening 25 can also be designed in another form, for example as a circular or semicircular opening and be arranged in the sealing piston 2 in the region of the guide surface 22 or in the opening enlargement region 23 .

Claims

1. An overpressure valve for regulated discharge of an overpressure of a gas, in particular CO2, from a refrigerant circuit of a vehicle, comprising: - a valve body (1), the valve body having a gas inlet (11) and a gas outlet (12) and a flow channel (13) connecting the gas inlet (11) and the gas outlet (12); a sealing piston (2) which is arranged in the flow channel (13) so as to be movable relative to a sealing surface (14) which is arranged on the valve body (1) and is in particular conical in shape, in particular along the axis of the valve body (1) and has a conical piston sealing surface (21), which in the closed state bears against the sealing surface (14) and closes the flow channel (13); - an adjusting screw (4) for adjusting the opening pressure, the adjusting screw being arranged in the valve body (1) in the flow channel (13) downstream of the sealing piston (2); as well as a spring (3), in particular a pressure spring, which is arranged between the sealing piston (2) and the adjusting screw (4) and which applies a closing force to the sealing piston (2) against the sealing surface (14); and wherein the sealing piston (2), the valve body (1) and the spring (3) are designed such that, when a defined pressure level at the gas inlet (11) is exceeded, the sealing piston (2) is displaced against the spring (3) in the opening direction and releases the passage cross section for the gas and, when the pressure level is fallen below, can return from the open state to the closed state, It is characterized in that - The piston sealing surface (21) has a piston angle (α) between 26° and 35°, in particular between 26.5° and 28.5°, wherein the sealing surface (14) of the valve body (1) has a valve body angle (β) between 27° and 38°, in particular between 30° and 31°, wherein the ratio of the valve body angle (β) to the piston angle (α) is 15 / 14≤β / α≤124 / 108.

2. An overpressure valve for regulated discharge of an overpressure of a gas, in particular CO 2 , from a refrigerant circuit of a vehicle, in particular according to claim 1 , comprising: - a valve body (1), the valve body having a gas inlet (11) and a gas outlet (12) and a flow channel (13) connecting the gas inlet (11) and the gas outlet (12); a sealing piston (2) which is arranged in the flow channel (13) so as to be movable relative to a sealing surface (14) which is arranged on the valve body (1) and is in particular conical in shape, in particular along the axis of the valve body (1) and has a conical piston sealing surface (21), which in the closed state bears against the sealing surface (14) and closes the flow channel (13); - an adjusting screw (4) for adjusting the opening pressure, the adjusting screw being arranged in the valve body (1) in the flow channel (13) downstream of the sealing piston (2); as well as a spring (3), in particular a pressure spring, which is arranged between the sealing piston (2) and the adjusting screw (4) and which applies a closing force to the sealing piston (2) against the sealing surface (14); and wherein the sealing piston (2), the valve body (1) and the spring (3) are designed such that, when a defined pressure level at the gas inlet (11) is exceeded, the sealing piston (2) is displaced against the spring (3) in the opening direction and releases the passage cross section for the gas and, when the pressure level is fallen below, can return from the open state to the closed state, It is characterized in that the sealing piston (2) has a guide surface (22) arranged downstream of the piston sealing surface (21) in the axial direction of the sealing piston (2), the sealing piston (2) being guided in the valve body (1) on the guide surface, and - The piston sealing surface (21) opens into an opening enlargement area (23) constructed in the sealing piston (2), and the opening enlargement area is arranged between the piston sealing surface (21) and the guide surface (22), wherein the sealing piston (2) has a larger projection area in the area of ​​the opening enlargement area (23) when viewed in the opening direction than an end face (24) of the sealing piston (2) arranged in the inlet of the flow channel (13).

3. The overpressure valve according to claim 1 or 2, characterized in that: The opening enlargement surface (23) transitions into the guide surface (22), wherein a through-gap (25) is formed in the sealing piston (2) in the transition area between the opening enlargement surface (23) and the guide surface (22) and / or in the guide surface (22), through which the gas flows in the open state into a gas collecting chamber (6) arranged downstream of the sealing piston (2), and excess pressure flows into the gas collecting chamber in the open state of the sealing piston (2) and can then escape through the gas collecting chamber via the flow channel (13), in particular via the adjusting screw (2) and the gas outlet (12) into the surrounding environment.

4. Overpressure valve according to any one of the preceding claims, characterized in that The ratio of the diameter (D2) of the sealing piston (2) at the guide surface (22) to the diameter (D1) of the valve body in the region of the guide surface (22) of the sealing piston is 291 / 290≤D1 / D2≤668 / 645, in particular 291 / 290≤D1 / D2≤148 / 145, The diameter (D1) of the valve body (1) at the guide surface (22) is 6.52 mm≤D1≤6.68 mm, in particular 6.62 mm≤D1≤6.66 mm.

5. The overpressure valve according to claim 3 or 4, characterized in that: The through-gap (25) is constructed as a certain number, in particular four, of flattened portions which are evenly distributed over the entire circumference of the sealing piston (2), wherein in particular the through-gap (25) is constructed in a stepped manner in the transition area between the enlarged opening area (23) and the guide surface (22) and in the guide surface (22).

6. Overpressure valve according to any one of the preceding claims, characterized in that The projected penetration area A3 of the gas at the adjusting bolt (3) is 0.7*Pi mm 2 ≤A3≤1.01*Pimm 2 , especially 0.74*Pimm 2 ≤A3≤1.0041*Pimm 2 .

7. Overpressure valve according to any one of the preceding claims, characterized in that The adjusting screw (4) is arranged in the valve body (1) in the region of the gas outlet (12) and closes the gas outlet, wherein the adjusting screw (4) has a number of through-holes (41) which are connected to the flow channel (13), in particular to a gas collecting chamber (6), and through which the pressure can escape from the gas collecting chamber (6) into the surrounding environment.

8. Overpressure valve according to any one of the preceding claims, characterized in that The sealing piston (2) is made of thermoplastic, in particular PEEK or PEKEKK, and the valve body (1) is made of metal, in particular an aluminum alloy or a steel alloy.

9. Overpressure valve according to any one of the preceding claims, characterized in that The adjusting screw (4) has a stop projection (8) pointing in the direction of the sealing piston (2) and / or the sealing piston (2) has a stop projection (8) pointing in the direction of the adjusting screw (4), wherein the stop projection (8) limits the maximum displacement travel of the sealing piston (2) in the opening direction in such a way that the guide surface (22) contacts the surface of the valve body (1) opposite the guide surface (22) when the pressure relief valve is maximally opened.

10. Overpressure valve according to any one of the preceding claims, characterized in that The spring (3) is installed in a prestressed state so that an optimum prestress of the spring (3) is present when the operating temperature of the pressure relief valve is reached, in particular a maximum operating temperature between 100° C. and 200° C., preferably between 150° C. and 160° C., wherein the spring (3) is installed in particular while being preheated to the operating temperature.

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