An oil level gauge pressure release valve

Abstract

The utility model discloses a kind of oil level gauge pressure release valves, it is related to oil level gauge technical field, including cover body, be arranged on the pressure relief hole of cover body, and be contained in the limit cap in cover body, indicating rod, spring, valve cover and valve body, valve body is fixed in cover body bottom;Valve body upper end is equipped with first sealing ring;Valve cover is movably housed in valve body upper end, spring is arranged in valve cover top, limit cap is arranged on spring upper end, valve cover is abutted with first sealing ring by spring effect, limit cap is abutted with cover body inner top by spring effect;Indicating rod is contained in spring interior, indicating rod upper end is movably arranged in limit cap, indicating rod lower end is non-fixedly contacted with valve cover;Indicating rod is stretched out cover body top by valve cover effect and is non-fixedly contacted with its indicating rod, so that indicating rod upper end is stretched out cover body and keeps, to directly, intuitively indicate whether the pressure relief action has ever occurred, it is convenient for operation and maintenance personnel to find pressure abnormal condition quickly.

Description

Technical Field

[0001] This utility model relates to the field of oil level gauge technology, and specifically to an oil level gauge pressure relief valve. Background Technology

[0002] In power and industrial fields, oil-filled electrical equipment such as oil-immersed transformers and oil-immersed reactors typically require the installation of oil level gauges to monitor changes in the volume of insulating oil with temperature. To ensure stable internal pressure and prevent damage to the oil level gauge body or observation window due to abnormal pressure (such as gas generation from internal faults or excessively high oil pressure caused by drastic temperature changes), oil level gauges are generally equipped with pressure relief valves (also known as breather valves or pressure relief valves).

[0003] Most common oil level gauge pressure relief valves use diaphragm or piston structures with built-in springs. Their basic working principle is: when the internal pressure of the equipment exceeds the preset trigger value of the spring, the valve opens to release pressure; when the pressure returns to normal, the valve automatically closes under the action of the spring and re-seals.

[0004] However, these traditional pressure relief valves lack mechanical action indication mechanisms, and maintenance personnel cannot directly visually determine whether the pressure relief valve has performed a pressure relief action. They must rely on additional pressure sensors for tracking and inspection, which is not conducive to the rapid detection of abnormal pressure conditions. Utility Model Content

[0005] The purpose of this utility model is to overcome the shortcomings of the prior art. This utility model provides an oil level gauge pressure relief valve. When the valve cover is over-pressurized, it lifts the indicator rod that is in non-fixed contact with it, so that the upper end of the indicator rod extends out of the cover and is held therein. This directly and intuitively indicates whether a pressure relief action has occurred, making it easier for maintenance personnel to quickly detect abnormal pressure conditions.

[0006] This utility model provides a pressure relief valve for an oil level gauge, including a cover, a pressure relief hole provided on the side wall of the cover, and a limiting cover, an indicator rod, a spring, a valve cover and a valve body housed in the cover. The valve body is fixedly provided at the bottom of the cover, and the valve body connects the cover and the internal space of the target oil level gauge based on its own internal longitudinal hollow channel. The upper end of the valve body is provided with a first sealing ring surrounding the hollow channel; the valve cover is movably covered over the upper end of the valve body; the spring is longitudinally arranged on the top of the valve cover; the limiting cover is arranged on the upper end of the spring; the valve cover abuts against the first sealing ring under the elastic action of the spring; the limiting cover abuts against the inner top of the cover under the elastic action of the spring. The indicator rod is longitudinally housed inside the spring, with its upper end movably passing through the limiting cover and its lower end in non-fixed contact with the valve cover; the indicator rod extends out of the top of the cover due to the lifting action of the valve cover.

[0007] Specifically, the top of the cover has a first window that exposes the upper end of the indicator rod; The upper surface of the limiting cover has a first limiting part protruding upward, which extends into the first window, and the outer peripheral surface of the first limiting part is in clearance fit with the inner peripheral surface of the first window; the upper end of the indicator rod is movably inserted through the center of the first limiting part.

[0008] Specifically, a first mounting cylinder is provided around the upper end of the indicator rod on the outer top of the cover. A shielding cover is provided on the first mounting cylinder. The side wall of the shielding cover is detachably connected to the side wall of the first mounting cylinder based on a first fastener. A top post is provided through the center of the top of the shielding cover. The end of the top post extends into the first mounting cylinder and abuts against the upper end of the indicator rod.

[0009] Specifically, a gasket is provided between the upper end of the indicator rod and the end of the top post, and the diameter of the gasket is larger than the diameter of the indicator rod.

[0010] Specifically, the limiting cover has a first through hole in the center, a protective sleeve is engaged in the first through hole, the upper end of the indicator rod is movably inserted in the protective sleeve, and the indicator rod extends out of the protective sleeve due to the lifting action of the valve cover.

[0011] Specifically, the lower surface of the limiting cover protrudes downward along the edge to form a limiting ring, the upper surface of the valve cover protrudes upward to form a limiting platform, the upper end of the spring is accommodated in the limiting ring, the lower end of the spring is sleeved on the limiting platform, and the lower end of the indicator rod is in non-fixed contact with the limiting platform.

[0012] Specifically, the lower surface of the valve cover has a wall portion protruding downward along the edge. There is a first gap between the outer peripheral surface of the wall portion and the inner peripheral surface of the cover body, and there is a second gap between the inner peripheral surface of the wall portion and the outer peripheral surface of the upper end of the valve body.

[0013] Specifically, the upper end of the valve body is recessed around the hollow channel to form a first annular groove, the main body of the first sealing ring is embedded in the first annular groove, the upper side of the first sealing ring protrudes upward outside the first annular groove, and the first sealing ring and the first annular groove are bonded together with structural adhesive.

[0014] Specifically, the outer peripheral surface of the valve body has a radially protruding mating part, the outer peripheral surface of the mating part is clearance-fitted with the inner peripheral surface of the cover, and the side wall of the cover and the mating part are fixedly connected based on a second fastener; The lower surface of the mating part is recessed around the hollow channel to form a second annular groove, and a second sealing ring is provided in the second annular groove; The lower end of the valve body serves as a connection part for connecting to the target oil level gauge, and a third annular groove is recessed around the hollow channel on the outer circumferential surface of the connection part.

[0015] Specifically, the cover includes a first cylindrical part, a transition part and a second cylindrical part connected in sequence from top to bottom. The upper surface of the limiting cover abuts against the inner top of the first cylindrical part. The valve body is fixedly installed at the bottom of the second cylindrical part. The pressure relief hole is installed on the side wall of the second cylindrical part. The diameter of the first cylindrical section is D1, the diameter of the transition section is D2, and the diameter of the second cylindrical section is D3. The constraint relationship between D1, D2, and D3 is as follows: D1 < D3 < D2.

[0016] Compared with the prior art, the beneficial effects of this utility model are: When overpressure occurs, the pressure medium (usually oil or gas) flowing into the hollow channel overcomes the spring resistance and pushes the valve cover upward away from the first sealing ring. The pressure medium then flows out of the hollow channel and is released to the outside through the pressure relief hole. At the same time, the lifted valve cover directly pushes the indicator rod upward, causing the upper end of the indicator rod to extend outside the cover. Since the indicator rod and the valve cover are not in fixed contact and can be separated, even if the pressure relief valve completes its pressure relief action and the valve cover is reset, the indicator rod will remain extended from the top of the cover (the indicator rod can be manually pressed and reset by maintenance personnel). This directly and intuitively indicates whether the pressure relief valve has performed a pressure relief action, making it easier for maintenance personnel to quickly detect abnormal pressure conditions. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the first cross-sectional structure of the oil level gauge pressure relief valve in this embodiment of the present invention; Figure 2 This is a schematic diagram of the second cross-sectional structure of the oil level gauge pressure relief valve in this embodiment of the present invention; Figure 3 This is a schematic diagram of the third cross-sectional structure of the oil level gauge pressure relief valve in this embodiment of the present invention; Figure 4 This is a schematic diagram of the fourth cross-sectional structure of the oil level gauge pressure relief valve in this embodiment of the present invention; Figure 5 This is a three-dimensional structural diagram of the valve body from the top view in an embodiment of this utility model; Figure 6 This is a three-dimensional structural diagram of the valve body from the bottom view in an embodiment of this utility model; Figure 7 This is a three-dimensional structural diagram of the oil level gauge pressure relief valve in an embodiment of this utility model.

[0019] In the attached drawings, 100 is the cover; 101 is the pressure relief hole; 102 is the first window; 103 is the first mounting cylinder; 110 is the first cylindrical part; 120 is the transition part; 130 is the second cylindrical part; 200 is the limiting cover; 201 is the first limiting part; 202 is the protective sleeve; 203 is the limiting ring; 300 is the indicator rod; 400 is the spring; 500 is the valve cover; 501 is the limiting platform; 502 is the enclosure part; 600 is the valve body; 601 is the hollow channel; 602 is the first annular groove; 603 is the second annular groove; 604 is the third annular groove; 610 is the mating part; 611 is the second fastener; 620 is the connecting part; 700 is the first sealing ring; 800 is the shielding cover; 801 is the first fastener; 802 is the top column; 803 is the gasket; and 900 is the second sealing ring. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0021] This utility model provides a pressure relief valve for an oil level gauge. Figure 1 This shows a first cross-sectional structural schematic diagram of the oil level gauge pressure relief valve in an embodiment of the present invention. Figure 2The diagram shows a second cross-sectional view of the oil level gauge pressure relief valve in an embodiment of the present invention. The oil level gauge pressure relief valve includes a cover 100, a pressure relief hole 101 disposed on the side wall of the cover 100, a limiting cover 200, an indicator rod 300, a spring 400, a valve cover 500, and a valve body 600 housed within the cover 100. The valve body 600 is fixedly disposed at the bottom of the cover 100, and the valve body 600 connects the cover 100 and the internal space of the target oil level gauge via a longitudinal hollow channel 601. A first sealing ring 700 is disposed around the hollow channel 601 at the upper end of the valve body 600. The valve cover 500 movably covers the valve body 600. At the upper end of 00, the spring 400 is longitudinally disposed on the top of the valve cover 500, and the limiting cover 200 is disposed on the upper end of the spring 400. The valve cover 500 abuts against the first sealing ring 700 under the elastic action of the spring 400, and the limiting cover 200 abuts against the inner top of the cover 100 under the elastic action of the spring 400. The indicator rod 300 is longitudinally housed inside the spring 400, the upper end of the indicator rod 300 is movably inserted through the limiting cover 200, and the lower end of the indicator rod 300 is in non-fixed contact with the valve cover 500. The indicator rod 300 extends out of the top of the cover 100 under the lifting action of the valve cover 500.

[0022] Please see Figure 2 When overpressure occurs, the pressure medium (usually oil or gas) flowing into the hollow channel 601 overcomes the resistance of the spring 400 and pushes the valve cover 500 upward away from the first sealing ring 700. The pressure medium then flows out of the hollow channel 601 and is released to the outside through the pressure relief hole 101. At the same time, the lifted valve cover 500 directly pushes the indicator rod 300 upward, causing the upper end of the indicator rod 300 to extend outside the cover 100. Since the indicator rod 300 and the valve cover 500 are not in fixed contact and can be separated, even if the pressure relief valve completes its pressure relief action and the valve cover 500 is reset, the indicator rod 300 will remain extended from the top of the cover 100 (the indicator rod 300 can be manually pressed and reset by maintenance personnel). This directly and intuitively indicates whether the pressure relief valve has performed its pressure relief action, making it easier for maintenance personnel to quickly detect abnormal pressure conditions.

[0023] In some specific embodiments, the indicator rod 300 is made entirely of red material, or the surface of the indicator rod 300 is coated with a red coating, making the color very bright and easy for maintenance personnel to visually identify the status of the indicator rod 300.

[0024] Specifically, the indicator rod 300 is a plastic rod or an aluminum alloy rod, which is lightweight, sturdy and durable.

[0025] Figure 3The diagram shows a third cross-sectional view of the oil level gauge pressure relief valve in this embodiment of the present invention. The top of the cover 100 has a first window 102, which exposes the upper end of the indicator rod 300. The upper surface of the limiting cover 200 has a first limiting part 201 protruding upward, which extends into the first window 102. The outer peripheral surface of the first limiting part 201 is in clearance fit with the inner peripheral surface of the first window 102. The upper end of the indicator rod 300 is movably inserted through the center of the first limiting part 201.

[0026] The first limiting part 201 extends into the first window 102 and uses a clearance fit, providing a precise and stable external guide mechanism for the up and down movement of the indicator rod 300. This effectively prevents the indicator rod 300 from deflecting, jamming, or getting tangled with the spring 400 during movement, ensuring smooth operation and accurate reset position, thereby enhancing the mechanical reliability of the entire indicator mechanism. Moreover, the first window 102 directly creates a dedicated observation channel for the upper end of the indicator rod 300, allowing a very clear visual contrast between the state of the indicator rod 300 extending out of the cover 100 (indicating action) and the state of retraction (indicating normal operation), greatly facilitating visual identification by maintenance personnel.

[0027] Figure 4 The diagram shows a fourth cross-sectional view of the oil level gauge pressure relief valve in this embodiment of the present invention. A first mounting cylinder 103 is provided around the upper end of the indicator rod 300 on the outer top of the cover 100. A shielding cover 800 is provided on the first mounting cylinder 103. The side wall of the shielding cover 800 is detachably connected to the side wall of the first mounting cylinder 103 based on a first fastener 801. A top post 802 is provided through the center of the top of the shielding cover 800. The end of the top post 802 extends into the first mounting cylinder 103 and abuts against the upper end of the indicator rod 300.

[0028] The shielding cover 800 is essentially a transport and storage protective cover. It is temporarily fixed to the first mounting cylinder 103 by the first fastener 801. During the transport and storage of the oil level gauge pressure relief valve, it provides a robust sealing protection for the upper end of the indicator rod 300 and the first window 102. Before the oil level gauge pressure relief valve is installed and put into operation on site, this shielding cover 800 is removed. After that, when the oil level gauge pressure relief valve is operating and being monitored during its life cycle, the indicator rod 300 and its first window 102 will be directly exposed and visible.

[0029] Moreover, during transportation, the oil level gauge pressure relief valve will experience bumps and vibrations, which can easily cause fluctuations in the force of the spring 400. This can lead to slight separation, vibration, or even relative movement between the valve cover 500 and the first sealing ring 700, which can easily affect the sealing performance or damage the sealing surface. By pressing the indicator rod 300 against the top column 802, the indicator rod 300 firmly presses the valve cover 500 onto the first sealing ring 700, preventing the valve cover 500 from moving due to vibration and effectively protecting the core sealing interface.

[0030] Specifically, the top post 802 is essentially a bolt, which is threaded into the cover 800 and can adjust the contact pressure on the indicator rod 300.

[0031] For further details, please refer to Figure 4 A gasket 803 is provided between the upper end of the indicator rod 300 and the end of the top post 802. The diameter of the gasket 803 is larger than the diameter of the indicator rod 300. The downward pressure applied by the top post 802 is transmitted to the upper end of the indicator rod 300 through the gasket 803. Since the diameter of the gasket 803 is larger than the diameter of the indicator rod 300, it disperses the high pressure, which was originally concentrated on the small end face of the indicator rod 300, into a large area of ​​low pressure. This effectively avoids indentation, plastic deformation, or even microcracks on the upper end face (especially the edge) of the indicator rod 300 under long-term compression, thus protecting the integrity of the indicator component.

[0032] In some specific embodiments, the shielding cover 800 is a first plastic cover, which is sturdy enough and has low manufacturing cost; the shielding cover 800 is made of red material as a whole, or the surface of the shielding cover 800 is provided with a red coating, the color is very bright, which makes it easy to remind maintenance personnel to remove the shielding cover 800 before the oil level gauge pressure relief valve is installed and put into operation on site.

[0033] In some specific embodiments, please refer to Figure 4 The limiting cover 200 has a first through hole in its center, and a protective sleeve 202 is engaged in the first through hole. The upper end of the indicator rod 300 is movably inserted through the protective sleeve 202. The indicator rod 300 extends out of the protective sleeve 202 due to the lifting action of the valve cover 500. The protective sleeve 202 can prevent the indicator rod 300 from directly rubbing against the limiting cover 200, effectively reducing the wear and jamming risk of the indicator rod 300, and ensuring the long-term smoothness and accuracy of the indicator rod 300's movement and reset.

[0034] Specifically, the sheath 202 includes a core cylinder and a rubber sleeve covering the core cylinder. The upper end of the indicator rod 300 is movably inserted into the core cylinder, and the rubber sleeve is engaged within the first through hole. The core cylinder can be made of wear-resistant, self-lubricating engineering plastics (such as POM) or copper alloys, achieving excellent friction pairing with the indicator rod 300, thus reducing costs while obtaining better motion performance. The rubber sleeve can be made of rubber or silicone, providing good elasticity and stable engagement within the first through hole.

[0035] In some specific embodiments, please refer to Figures 1 to 4 The lower surface of the limiting cover 200 protrudes downward along its edge to form a limiting ring 203, and the upper surface of the valve cover 500 protrudes upward to form a limiting platform 501. The upper end of the spring 400 is housed within the limiting ring 203, and the lower end of the spring 400 is sleeved on the limiting platform 501. The lower end of the indicator rod 300 is in non-fixed contact with the limiting platform 501. The limiting ring 203 and the limiting platform 501 radially constrain the spring 400 from its upper and lower ends, respectively, ensuring that the spring 400 maintains vertical and coaxial movement during compression and release. This effectively prevents the spring 400 from tilting or jumping out, thereby ensuring that the pressure applied to the valve cover 500 is uniform, stable, and consistent in direction, greatly improving the reliability of the sealing and reset actions.

[0036] In some specific embodiments, the limiting cover 200 is a second plastic cover, which is strong enough and has low manufacturing cost.

[0037] In some specific embodiments, please refer to Figures 1 to 4 The lower surface of the valve cover 500 has a wall portion 502 protruding downward along the edge. There is a first gap space between the outer peripheral surface of the wall portion 502 and the inner peripheral surface of the cover 100, and there is a second gap space between the inner peripheral surface of the wall portion 502 and the outer peripheral surface of the upper end of the valve body 600.

[0038] The enclosure portion 502 itself constitutes the downward-extending skirt of the valve cover 500. The first gap space between it and the inner wall of the cover 100, and the second gap space between it and the outer wall of the valve body 600, together form a double-cylinder coaxial non-contact guide channel. During the entire process of the pressure medium pushing the valve cover 500 upward, the pressure medium itself fills the second gap space and the first gap space. This makes the "enclosure portion 502" of the valve cover 500 actually suspended in the flowing pressure medium, obtaining uniform radial support and realizing a near-frictionless, centered vertical movement. This effectively avoids direct mechanical friction with any fixed parts, ensuring that the valve cover 500 moves extremely smoothly without jamming and without wear during long-term use.

[0039] Moreover, the enclosure 502 can effectively prevent particulate pollutants from falling into the valve cover 500, thereby significantly reducing the risk of particulate pollutants affecting the sealing performance of the valve cover 500.

[0040] Specifically, the width of the first interval space is greater than the width of the second interval space. The wider first interval space and the narrower second interval space form an efficient and controllable pressure relief channel: the narrower second interval space serves as the first annular channel into which the pressure medium flows after opening the valve cover 500. Its narrower width helps maintain a certain flow velocity and pressure in the initial stage, ensuring that the valve cover 500 can be quickly and fully opened, and providing initial guidance for the expansion of the pressure medium. Subsequently, the pressure medium enters the wider first interval space, realizing the rapid expansion of the channel, allowing the high-pressure medium to be quickly depressurized, decelerated, and diffused, and smoothly guided to the side pressure relief hole 101 for discharge. This "narrow-then-wide" channel design ensures both responsiveness and optimizes the relief efficiency, reducing turbulence and whistling.

[0041] Moreover, after the pressure relief is completed, the valve cover 500 returns to its original position under the action of the spring 400. At this time, the pressure medium remaining in the two interval spaces can be smoothly squeezed out. The narrower second interval space plays a more precise guiding role at the end of the reset, ensuring that the sealing surface of the valve cover 500 and the first sealing ring 700 on the valve body 600 are circumferentially and evenly fitted, so as to achieve a reliable seal.

[0042] Figure 5 This diagram shows a three-dimensional view of the valve body from the top perspective in an embodiment of the present invention. The upper end of the valve body 600 is recessed around the hollow channel 601, forming a first annular groove 602. Please refer to the accompanying drawings. Figures 1 to 4 The main body of the first sealing ring 700 is embedded in the first annular groove 602, and the upper side of the first sealing ring 700 protrudes upward outside the first annular groove 602. The first sealing ring 700 and the first annular groove 602 are bonded together with structural adhesive.

[0043] The first annular groove 602 provides precise three-dimensional positioning and circumferential constraint for the first sealing ring 700, firmly accommodating its body and preventing radial creep or overall torsion under repeated impacts or long-term vibrations of the valve cover 500. This is the foundation for ensuring accurate positioning of the sealing surface. Based on this, structural adhesive is used for bonding, achieving a molecular-level bond between the first sealing ring 700 and the valve body 600. This adds a strong axial and circumferential adhesion force to the first sealing ring 700, avoiding the risk of it being "blown out" of the first annular groove 602 under extreme operating conditions or loosening due to material aging, achieving extremely secure fixation.

[0044] Moreover, please see Figures 1 to 4The first sealing ring 700 has a first annular groove 602 protruding on its upper side, which ensures that when the first sealing ring 700 contacts the sealing surface of the valve cover 500, it can generate sufficient and controllable compression deformation to form an effective sealing line.

[0045] In some specific embodiments, please refer to Figures 1 to 5 The valve body 600 has a radially protruding mating part 610 on its outer peripheral surface. The outer peripheral surface of the mating part 610 is clearance-fitted with the inner peripheral surface of the cover 100. The side wall of the cover 100 and the mating part 610 are fixedly connected based on a second fastener 611. The mating part 610 acts as a radial positioning boss on the valve body 600, and its clearance fit with the inner wall of the cover 100 allows for quick and natural initial coaxial alignment during assembly. The second fastener 611 (such as a screw) then provides final locking. This "positioning first, then fastening" design ensures precise alignment between the valve body 600 and the cover 100, providing a solid structural framework for the smooth movement and precise reset of the valve cover 500.

[0046] Figure 6 This diagram shows a three-dimensional view of the valve body from the bottom of an embodiment of the present invention. The lower surface of the mating part 610 is recessed around the hollow channel 601, forming a second annular groove 603. Please refer to the accompanying drawings. Figures 1 to 4 A second sealing ring 900 is provided in the second annular groove 603. The second sealing ring 900 is installed on the lower surface of the mating part 610. Its function is to form a key end face static seal at the mating end face of the valve body 600 and the target oil level gauge. Its compression is ≥40%, which effectively reduces the risk of the pressure medium inside the target oil level gauge leaking directly to the outside.

[0047] For further details, please refer to Figure 6 The lower end of the valve body 600 serves as a connecting part 620 for connecting to the target oil level gauge. A third annular groove 604 is recessed around the hollow channel 601 on the outer circumferential surface of the connecting part 620. The third annular groove 604 does not hold a sealing ring and is used to cooperate with the interface structure (such as a snap ring or a sleeve boss) of the target oil level gauge body to achieve quick installation of the valve body 600. This design simplifies the assembly relationship between the valve body 600 and the oil level gauge, concentrates the sealing function on the aforementioned end face sealing (second sealing ring 900), and separates the connection function from the structure of the third annular groove 604, achieving clear separation of functions and improving the reliability and manufacturability of the assembly.

[0048] Figure 7 This diagram shows a three-dimensional structural schematic of the oil level gauge pressure relief valve in an embodiment of the present invention. The cover 100 includes, from top to bottom, a first cylindrical portion 110, a transition portion 120, and a second cylindrical portion 130, which are sequentially connected as a single unit. Please refer to the attached diagram. Figures 1 to 4 The upper surface of the limiting cover 200 abuts against the inner top of the first cylindrical part 110, the valve body 600 is fixedly disposed at the bottom of the second cylindrical part 130, and the pressure relief hole 101 is disposed on the side wall of the second cylindrical part 130. The diameter of the first cylindrical portion 110 is D1, the diameter of the transition portion 120 is D2, and the diameter of the second cylindrical portion 130 is D3. The constraint relationship between D1, D2, and D3 is as follows: D1 < D3 < D2.

[0049] The first cylindrical section 110 (with the smallest diameter D1) matches the dimensions of the limiting cover 200 and the spring 400, providing a well-guided channel for the extension and retraction of the spring 400; the second cylindrical section 130 (with the middle diameter D3) needs to accommodate the valve body 600 and the valve cover 500, and provide movement space for the valve cover 500, as well as pressure relief space for the pressure medium; the transition section 120 (with the largest diameter D2) can shield the lower second cylindrical section 130 to a certain extent, thereby reducing the probability of dust and other particles falling into the pressure relief hole 101.

[0050] The working principle of the oil level gauge pressure relief valve of this utility model is as follows: Before the oil level gauge pressure relief valve is put into use, the cover 800 needs to be removed.

[0051] When overpressure occurs, the pressure medium (usually oil or gas) flowing into the hollow channel 601 overcomes the resistance of the spring 400 and pushes the valve cover 500 upward away from the first sealing ring 700. The pressure medium then flows out of the hollow channel 601 and is released to the outside through the pressure relief hole 101. At the same time, the lifted valve cover 500 directly pushes the indicator rod 300 upward, causing the upper end of the indicator rod 300 to extend outside the cover 100. Since the indicator rod 300 and the valve cover 500 are not in fixed contact and can be separated, even if the pressure relief valve completes its pressure relief action and the valve cover 500 is reset, the indicator rod 300 will remain extended from the top of the cover 100 (the indicator rod 300 can be manually pressed and reset by maintenance personnel). This directly and intuitively indicates whether the pressure relief valve has performed a pressure relief action, making it easier for maintenance personnel to quickly detect abnormal pressure conditions.

[0052] The oil level gauge pressure relief valve of this invention uses a valve cover 500 to lift an indicator rod 300 that is not in fixed contact with the valve when there is overpressure. This causes the upper end of the indicator rod 300 to extend out of the cover 100 and remain there, thus directly and intuitively indicating whether a pressure relief action has occurred, making it easy for maintenance personnel to quickly detect abnormal pressure conditions. Moreover, the oil level gauge pressure relief valve of this invention has a simple and reliable structure, requires no complex electrical or sensing components, is reliable in operation, low in cost, and easy to maintain.

[0053] The above provides a detailed description of an oil level gauge pressure relief valve provided by the embodiments of this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A pressure relief valve for an oil level gauge, characterized in that, It includes a cover, a pressure relief hole provided on the side wall of the cover, and a limiting cover, an indicator rod, a spring, a valve cover and a valve body housed in the cover. The valve body is fixedly provided at the bottom of the cover and the valve body connects the cover and the internal space of the target oil level gauge through its own internal longitudinal hollow channel. The upper end of the valve body is provided with a first sealing ring surrounding the hollow channel; the valve cover is movably covered over the upper end of the valve body; the spring is longitudinally arranged on the top of the valve cover; the limiting cover is arranged on the upper end of the spring; the valve cover abuts against the first sealing ring under the elastic action of the spring; the limiting cover abuts against the inner top of the cover under the elastic action of the spring. The indicator rod is longitudinally housed inside the spring, with its upper end movably passing through the limiting cover and its lower end in non-fixed contact with the valve cover; the indicator rod extends out of the top of the cover due to the lifting action of the valve cover.

2. The oil level gauge pressure relief valve as described in claim 1, characterized in that, The top of the cover has a first window, which exposes the upper end of the indicator rod; The upper surface of the limiting cover has a first limiting part protruding upward, which extends into the first window, and the outer peripheral surface of the first limiting part is in clearance fit with the inner peripheral surface of the first window; the upper end of the indicator rod is movably inserted through the center of the first limiting part.

3. The oil level gauge pressure relief valve as described in claim 1 or 2, characterized in that, A first mounting cylinder is provided around the upper end of the indicator rod on the outer top of the cover. A shielding cover is provided on the first mounting cylinder. The side wall of the shielding cover is detachably connected to the side wall of the first mounting cylinder based on a first fastener. A top post is provided through the center of the top of the shielding cover. The end of the top post extends into the first mounting cylinder and abuts against the upper end of the indicator rod.

4. The oil level gauge pressure relief valve as described in claim 3, characterized in that, A shim is provided between the upper end of the indicator rod and the end of the top post, and the diameter of the shim is larger than the diameter of the indicator rod.

5. The oil level gauge pressure relief valve as described in claim 1 or 2, characterized in that, The limiting cover has a first through hole in the center, and a protective sleeve is snapped into the first through hole. The upper end of the indicator rod is movably inserted into the protective sleeve, and the indicator rod extends out of the protective sleeve due to the lifting action of the valve cover.

6. The oil level gauge pressure relief valve as described in claim 1 or 2, characterized in that, The lower surface of the limiting cover protrudes downward along the edge to form a limiting ring, the upper surface of the valve cover protrudes upward to form a limiting platform, the upper end of the spring is housed in the limiting ring, the lower end of the spring is sleeved on the limiting platform, and the lower end of the indicator rod is in non-fixed contact with the limiting platform.

7. The oil level gauge pressure relief valve as described in claim 1, characterized in that, The lower surface of the valve cover protrudes downward along the edge to form a wall portion. There is a first gap between the outer peripheral surface of the wall portion and the inner peripheral surface of the cover body, and there is a second gap between the inner peripheral surface of the wall portion and the outer peripheral surface of the upper end of the valve body.

8. The oil level gauge pressure relief valve as described in claim 1 or 7, characterized in that, The upper end of the valve body is recessed around the hollow channel and has a first annular groove. The main body of the first sealing ring is embedded in the first annular groove, and the upper side of the first sealing ring protrudes upward outside the first annular groove. The first sealing ring and the first annular groove are bonded together with structural adhesive.

9. The oil level gauge pressure relief valve as described in claim 1 or 7, characterized in that, The outer peripheral surface of the valve body is radially protruding and has a mating part. The outer peripheral surface of the mating part is clearance-fitted with the inner peripheral surface of the cover. The side wall of the cover and the mating part are fixedly connected based on a second fastener. The lower surface of the mating part is recessed around the hollow channel to form a second annular groove, and a second sealing ring is provided in the second annular groove; The lower end of the valve body serves as a connection part for connecting to the target oil level gauge, and a third annular groove is recessed around the hollow channel on the outer circumferential surface of the connection part.

10. The oil level gauge pressure relief valve as described in claim 1, characterized in that, The cover consists of a first cylindrical part, a transition part, and a second cylindrical part connected in sequence from top to bottom. The upper surface of the limiting cover abuts against the inner top of the first cylindrical part. The valve body is fixedly installed at the bottom of the second cylindrical part. The pressure relief hole is installed on the side wall of the second cylindrical part. The diameter of the first cylindrical section is D1, the diameter of the transition section is D2, and the diameter of the second cylindrical section is D3. The constraint relationship between D1, D2, and D3 is as follows: D1 < D3 < D2.

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