Pressure release valve structure on oil-immersed transformer
By designing a combined pressure relief valve structure, the problem of high maintenance costs for oil-immersed transformers under load fluctuations and harsh environments was solved, and flexible switching between reversible and irreversible pressure relief was achieved, reducing the frequency and cost of transformer maintenance.
Patent Information
- Application Number
- CN202423125520.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-12-17
AI Technical Summary
The pressure relief valves of existing oil-immersed transformers have high maintenance costs due to frequent load fluctuations and harsh environments, and the irreversible pressure relief measures lead to frequent major overhauls of the transformers.
A pressure relief valve structure including a valve tube, valve stem, piston, overflow hole, and preload spring was designed. By combining the overflow hole and the primary pressure relief hole, two pressure relief methods, reversible and irreversible, are achieved to deal with slow and sudden oil pressure changes respectively, thus avoiding contamination of transformer oil.
This expands the transformer's applicability, reduces maintenance frequency, decreases transformer downtime and maintenance costs, and extends equipment lifespan.
Smart Images
Figure CN223511586U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of transformer technology and relates to a pressure relief valve structure on an oil-immersed transformer. Background Technology
[0002] Oil-immersed transformers come in two types: those with oil conservator (using an oil conservator and a breather to cope with changes in oil pressure within the transformer tank) and those utilizing heat sink deformation (using heat sink deformation to cope with oil pressure changes). For heat sink deformation type transformers, to improve safety and protect the tank when the oil pressure reaches the heat sink deformation limit, a pressure relief valve is generally connected to the inner cavity of the tank. Currently, these pressure relief valves are piston or ball valve type. When the oil pressure reaches a certain level, the pressure relief valve opens, allowing the inner cavity of the tank to connect with the outside and release pressure, protecting the tank. In this method, to ensure the instantaneous pressure relief effect, the pressure release instantaneously breaks through the seal on the valve sleeve, which is an irreversible protective measure. Although the probability of the pressure relief valve opening is low, the pneumatic pressure relief means that the transformer needs major overhaul, including oil replacement and pressure relief valve replacement. When dealing with transformer installation environments with frequent load fluctuations and harsh external environments, the maintenance cost is low and the triggering frequency is high. Utility Model Content
[0003] The purpose of this invention is to address the aforementioned problems in existing technologies by providing a pressure relief valve structure for oil-immersed transformers. The technical problem this invention aims to solve is how to expand the adaptability of transformers.
[0004] The objective of this utility model can be achieved through the following technical solution: A pressure relief valve structure for an oil-immersed transformer, characterized in that it includes a valve pipe communicating with the oil tank of the oil-immersed transformer, a valve stem slidably connected longitudinally inside the valve pipe, two pistons fixedly arranged alternately on the valve stem, the inner cavity of the valve pipe including a guide portion cooperating with the valve stem and a sliding portion cooperating with the pistons, an overflow hole opened on the valve stem, the inlet of the overflow hole being located at the lower end face of the valve stem, and the outlet of the overflow hole being located on the valve stem wall between the two pistons; a primary pressure relief hole is opened on the valve pipe, a preload spring is connected between the piston near the lower end of the valve stem and the valve pipe; the primary pressure relief hole can communicate with the outlet of the overflow hole when the preload spring is stretched to the point where the valve stem has not yet disengaged from the guide portion, the top of the valve pipe has a sealing cover, and the valve stem can abut against the lower surface of the sealing cover after the valve stem disengages from the guide portion.
[0005] Furthermore, a rubber sleeve is wrapped around the valve tube, and the primary pressure relief hole is located inside the rubber sleeve.
[0006] Furthermore, the outer edge of the sealing cover has a dust cover.
[0007] This pressure relief valve has two pressure relief modes. The first is a low-pressure relief mode, where the valve stem rises to the point where the overflow outlet connects with the primary pressure relief port. In this mode, transformer oil from the tank enters between the two pistons through the overflow port and then into the rubber sleeve through the primary pressure relief port, causing the rubber sleeve to expand and achieving initial pressure relief to cope with a slow increase in oil pressure. When the oil pressure suddenly increases for some reason, the overflow port cannot reduce the pressure by overflowing transformer oil in time. The valve stem disengages from the guide, causing the piston to move rapidly upwards. The top of the valve stem ruptures the sealing cover, achieving instantaneous pressure relief. The first pressure relief method is reversible, allowing normal operation after the oil pressure decreases, and it does not contaminate the transformer oil. The second type of pressure relief, the irreversible pressure relief, is the same as existing transformer pressure relief valves. In this case, the transformer requires maintenance and repair. Therefore, this solution can adapt to a wider range of application scenarios and, in most cases, will not cause transformer downtime. Attached Figure Description
[0008] Figure 1 This is a schematic diagram showing the location of the pressure relief valve on the transformer.
[0009] Figure 2 This is a schematic diagram of the pressure relief valve in a low-pressure state.
[0010] Figure 3 This is a schematic diagram of the pressure relief valve when it releases pressure through the primary pressure relief hole.
[0011] Figure 4 This is a schematic diagram of the structure when the pressure relief valve's sealing cover is against the valve stem.
[0012] In the diagram, 1. Valve pipe; 2. Valve stem; 3. Piston; 4. Overflow hole; 5. Primary pressure relief hole; 6. Sealing cover; 7. Rubber sleeve; 8. Dust cover. Detailed Implementation
[0013] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.
[0014] like Figure 1 and Figure 2The pressure relief valve structure shown on the oil-immersed transformer includes a valve pipe 1 communicating with the oil tank of the oil-immersed transformer. A valve stem 2 is longitudinally slidably connected inside the valve pipe 1. Two pistons 3 are fixedly mounted on the valve stem 2, arranged alternately. The inner cavity of the valve pipe 1 includes a guide portion that cooperates with the valve stem 2 and a sliding portion that cooperates with the pistons 3. An overflow hole 4 is opened on the valve stem 2. The inlet of the overflow hole 4 is located at the lower end face of the valve stem 2, and the outlet of the overflow hole 4 is located on the wall surface of the valve stem 2 between the two pistons 3. A primary pressure relief hole 5 is opened on the valve pipe 1. A preload spring is connected between the piston 3 near the lower end of the valve stem 2 and the valve pipe 1. The primary pressure relief hole 5 can communicate with the outlet of the overflow hole 4 when the preload spring is stretched to the point where the valve stem 2 has not yet disengaged from the guide portion. The top of the valve pipe 1 has a sealing cover 6, and the valve stem 2 can abut against the lower surface of the sealing cover 6 after the valve stem 2 disengages from the guide portion. A rubber sleeve 7 is wrapped around the valve pipe 1, the primary pressure relief hole 5 is located inside the rubber sleeve 7, and a dust cover 8 is provided on the outer edge of the sealing cover 6.
[0015] This pressure relief valve has two pressure relief states. One is a low-pressure relief state, that is, when the valve stem 2 rises to the point where the outlet of the overflow hole 4 is connected to the primary pressure relief hole 5. At this time, the transformer oil in the tank enters between the two pistons 3 through the overflow hole 4 and enters the rubber sleeve 7 through the primary pressure relief hole 5, causing the rubber sleeve 7 to expand. Figure 3 As shown, this allows for initial pressure relief to address a slow increase in oil pressure. However, if the oil pressure suddenly increases for some reason, the overflow orifice 4 cannot reduce the pressure by overflowing transformer oil in time. The valve stem 2 disengages from the guide, causing the piston 3 to move rapidly upwards. Figure 4 As shown, the top of valve stem 2 punctures the sealing cover 6, achieving instantaneous pressure relief. The first type of pressure relief is reversible, allowing the valve to continue operating normally even after the oil pressure drops, and it does not contaminate the transformer oil. The second type of pressure relief, however, is irreversible, similar to existing transformer pressure relief valves. In this case, the transformer requires repair and maintenance. Therefore, this solution can adapt to a wider range of application scenarios and, in most cases, will not cause transformer downtime.
[0016] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.
Claims
1. A pressure relief valve structure for an oil-immersed transformer, characterized in that, The system includes a valve pipe (1) connected to the oil tank of an oil-immersed transformer. A valve stem (2) is longitudinally slidably connected inside the valve pipe (1). Two pistons (3) are fixedly mounted on the valve stem (2) and arranged alternately. The inner cavity of the valve pipe (1) includes a guide portion that cooperates with the valve stem (2) and a sliding portion that cooperates with the pistons (3). An overflow hole (4) is provided on the valve stem (2). The inlet of the overflow hole (4) is located on the lower end face of the valve stem (2), and the outlet of the overflow hole (4) is located on both pistons (3). The valve stem (2) wall between the pistons (3); a primary pressure relief hole (5) is provided on the valve tube (1), and a pre-tightening spring is connected between the piston (3) near the lower end of the valve stem (2) and the valve tube (1); the primary pressure relief hole (5) can communicate with the outlet of the overflow hole (4) when the pre-tightening spring is stretched to the point where the valve stem (2) has not yet disengaged from the guide; the top of the valve tube (1) has a sealing cover (6), and the valve stem (2) can abut against the lower surface of the sealing cover (6) after the valve stem (2) disengages from the guide.
2. The pressure relief valve structure for an oil-immersed transformer according to claim 1, characterized in that, The valve tube (1) is wrapped with a rubber sleeve (7), and the primary pressure relief hole (5) is located inside the rubber sleeve (7).
3. The pressure relief valve structure for an oil-immersed transformer according to claim 1 or 2, characterized in that, The outer edge of the sealing cover (6) has a dust cover (8).