CN2859161Y - Water-cooled connector for gate circuit transistor valve assembly - Google Patents

Abstract

The utility model relates to a water-cooling connecting piece for a thyristor valve group, which relates to a cooling device for a thyristor valve group in a power electronic system. It consists of five parts: stud screw, lock nut, water distribution conduit, O-ring, and water distribution nut. Both ends of the double-ended screw are threaded, and the bottom of the thread at one end is equipped with a sealing groove, in which an O-ring is installed to form a static external seal; the thread at the other end is connected with the lock nut, and the inside is a through-hole structure; locking The nut is nested on the water distribution pipe; when the inner bottom step of the lock nut and the top end surface of the double-headed screw reach the locked state, the precision nylon water distribution pipe sealing step ring is squeezed, so that the sealing step ring is deformed by axial force uniformly to form a joint The inner seal; the water distribution nut is cylindrical, the bottom is a concave spherical surface, the internal through hole is hexagonal, and the thread of the water distribution nut matches the thread of the double-headed screw. It does not contain metal components, is resistant to high voltage, and can be used for a long time in a high voltage environment.

Description

Thyristor valve group water cooling connector

technical field

The utility model relates to a cooling device for a thyristor valve group in an electric power system and power electronics technology, in particular to a water-cooling connection piece for a high-voltage and high-power thyristor valve group.

Background technique

The thyristor valve is the core component of the static var compensator (SVC) in the power system. By controlling the firing angle of the thyristor valve, the impedance can be continuously adjusted, which can enhance the power transmission capacity of the system, improve system stability and damp power oscillation. When a line fault occurs, the protection of the static var compensator can also be realized by controlling the continuous conduction of the thyristor valve. The thyristor valve used in the static var compensator must withstand high voltage and high current, and it needs to be realized by connecting multiple high-power thyristors in series and parallel.

With the continuous wide application of closed circulating water cooling system equipment using ultra-high-purity water as cooling medium in high-voltage and high-power power electronic devices, the water-cooling connector is used for cooling between the closed circulating water cooling transmission and distribution system and the reactive power compensation thyristor valve group. Connection channels for medium (pure water) delivery. The form and structure of the water-cooling connector should ensure the effective connection between the power electronic devices of the thyristor valve group and the water transmission and distribution pipeline, so that the ultra-high-purity water circulating operation as the cooling medium will not cause leakage in the closed system, and can be used for a long time in a high-voltage environment . At present, most of the materials used in the connectors and quick connectors that are mainly used in hydraulic and pneumatic systems in my country contain metal materials, and they are of a single sealing structure. Connectors containing metal materials may affect the high-voltage electric field of the thyristor valve group, and even produce discharge phenomena, thus affecting the water quality of ultra-high-purity water as the cooling medium, which may cause metal corrosion and make the sealing performance invalid. If other plastic connectors are used, they cannot fully meet the requirements for long-term use in high-voltage environments, and this plastic connector must also meet the requirements of different thermal expansion coefficients due to the rise and fall of temperature when the closed water cooling system is working. The requirements for tight fit of material products and the requirements for ultra-low water resistance loss are difficult for plastic material connectors to meet. Therefore, the design and operation of the thyristor valve group requires a special water-cooled connector with a new type of insulating material and high voltage resistance.

Contents of the invention

In order to overcome the above-mentioned defects in the prior art, the purpose of this utility model is to provide a water-cooled connector that does not contain metal components, is resistant to high voltage, and can be used for a long time in a high-voltage environment.

The technical scheme that the utility model solves its technical problem to take is:

The utility model is composed of five parts: a double-head screw, a locking nut, a water distribution conduit, an O-shaped sealing ring and a water distribution nut.

Both ends of the double-ended screw are threaded, and the bottom of the thread at one end is equipped with a sealing groove, in which an O-ring is installed to form a static external seal and effectively prevent leakage; the thread at the other end is connected with the lock nut, and the inside is Through-hole structure; the lock nut is inserted into a certain length of precision nylon water distribution conduit; there are two sealing step rings under the two ends of the water distribution conduit, so that the lock nut is nested on the water distribution conduit; the inner bottom step of the lock nut When the top end face of the stud screw reaches the locked state, squeeze the sealing step ring of the precision nylon water distribution conduit, so that the sealing step ring is uniformly stressed and deformed in the axial direction, forming the inner seal of the joint; the water distribution nut is cylindrical, and the bottom is concave Spherical surface, the internal through hole is hexagonal, the thread of the water distribution nut matches the thread of the stud screw. The stud screw is made of polyamide plastic (PA12); the lock nut is made of random copolymer polypropylene (PPR); the O-ring is made of EPDM; the water distribution nut is made of random copolymer Made of polypropylene (PPR).

Selection of materials for the above components:

1. Polyamide plastic (PA12), which belongs to heterochain polymers, the issues of concern in the selection of materials are:

①Mechanical properties: high tensile strength, impact strength, toughness, rigidity, strength is less affected by temperature and humidity, excellent self-lubricating properties;

②Thermal properties: thermal conductivity is very small, 0.25W/m.k;

③Electrical properties: Volume resistivity is 1.83×10 ¹⁵ Ω.cm, dielectric constant is 1.63 at 1MHz, excellent aging performance under high voltage;

④Environmental performance: excellent chemical resistance, excellent alkali hydrolysis resistance;

2. Random copolymerized polypropylene (PPR), which belongs to linear carbon chain polymers, the issues of concern in the selection of materials are:

① Mechanical properties: good mechanical properties, high tensile strength, impact strength, surface hardness and rigidity, mechanical properties are less affected by temperature, and good wear resistance;

②Thermal properties: Good heat resistance, can be used continuously at 100-120 °C, and can be used at 150 °C without deformation under the action of external force;

③Electrical properties: required for non-polar polymers, with excellent electrical insulation properties, volume resistivity of 1×10 ¹⁶ Ω.cm, dielectric constant of 2.2 at 1 MHz, and excellent aging properties under high voltage;

④Environmental performance: high chemical corrosion resistance;

3. Ethylene Propylene Diene Monomer (EPDM), with ethylene and propylene as the main raw materials, the issues of concern in the selection of materials are:

① Weather resistance, aging resistance in the air, good oil resistance;

② A material commonly used as a seal.

Owing to adopting above technical scheme, the beneficial effect of the utility model is:

1. All-plastic insulation structure simplifies the electrical design of the thyristor valve group;

2. It has a reliable internal and external sealing structure, and can withstand a pressure of 1MPa within the temperature range of 10-55°C;

3. The characteristics of ultra-low water resistance loss, when the flow rate is 1-5L/min, the water resistance loss is 0.01-0.04bar;

4. The selection of different materials matches the coefficient of thermal expansion;

5. Strict control of product size tolerance accuracy ensures the sealing effect;

6. Under the conditions of high voltage, high water pressure, high temperature and temperature changes, it is resistant to aging and has a long service life.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Fig. 1 is the general assembly drawing of the present utility model.

Fig. 2 shows the front view and the A-direction view of the stud screw of the water-cooling connector of the present invention.

Fig. 3 shows three views of the locking nut of the water-cooling connector of the present invention.

Fig. 4 is a front view and a cross-sectional view of the O-ring of the water-cooling connector of the present utility model.

Fig. 5 is a three-view diagram of the water distribution nut of the water-cooling connector of the utility model.

Detailed ways

Referring to FIG. 1 , the water-cooling connector consists of five parts: a stud screw 3 , a lock nut 5 , a water distribution conduit 2 , an O-ring 4 , and a water distribution nut 1 .

Referring to Fig. 2, it is the stud screw 3 of the water-cooled connector of the present invention.

Both ends of the double-ended screw 3 are threaded, and the bottom of the thread at one end is equipped with a sealing groove, and an O-ring 4 is installed in the sealing groove to form a static external seal to effectively prevent leakage; the other end is an M10 thread, which is connected with the lock nut Mating connection; inside is a through-hole structure.

Stud screw 3 adopts polyamide plastics (PA12) to make. The selection of materials takes into account various factors such as comprehensive heat transfer efficiency, mechanical strength and corrosion between the plastic and the connection part of the power electronic device. The processing method of mold injection molding is adopted.

processing method:

A. When the product has a double-thread structure, reasonable selection of the parting surface can make the structure of the mold simple and the plastic parts easy to form, thereby obtaining a high-quality product. The double-ended screw of the present invention chooses the sealing end surface as the parting surface. Profile.

B. Due to the special structure of the double-headed screw, both ends are threaded, so the mold is equipped with a motor demoulding mechanism, and the hexagonal end surface on the product is used as the anti-rotation mechanism, so that after the mold is opened, the plastic part is threaded. The core cannot be attached to the motor.

It can be rotated to achieve the effect of automatic demoulding, which greatly improves the production efficiency.

I. The calculation method of the large, medium and small diameter of the threaded ring is as follows:

α—coordination coefficient value;

D(M, 1M, 2M) - thread diameter (mm);

d _{S, 1S, 2S} - the nominal size of the outer thread of the plastic part, the size of the large, small and middle diameter;

Scp - the average shrinkage of the plastic used;

b——The tolerance of the large, small, and middle diameters corresponding to the thread of the plastic part, its value can refer to the metal thread tolerance standard GB197-81;

δ _z ——The manufacturing tolerance of the large, small and medium diameters corresponding to the thread, see Table 1-1.

Table 1-1 thread type Thread diameter D or d Manufacturing tolerance δ _z Thread diameter D or d Manufacturing tolerance δ _z Large diameter middle diameter trail Large diameter middle diameter trail Coarse teeth 3-12 0.03 0.02 0.03 36-45 0.05 0.04 0.05 14-33 0.04 0.03 0.04 48-68 0.06 0.05 0.06 fine teeth 4-22 0.03 0.02 0.03 6-27 0.03 0.02 0.03 24-52 0.04 0.03 0.04 30-52 0.04 0.03 0.04 56-68 0.05 0.04 0.05 56-72 0.05 0.04 0.05

II. P _M =α(P _s +PsS _cp %)±δ _z `/2 (1-2)

α—coordination coefficient value;

P _M ——Thread ring pitch (mm);

Ps——Nominal size of external thread pitch of plastic parts (mm);

Scp - the average shrinkage of the plastic used;

δ _z ——The manufacturing tolerance of threaded ring pitch, see Table 1-2.

Table 1-2 Thread diameter D or d fit length Manufacturing tolerance δ _z 3-10 -12 0.01-0.03 12-22 >12-20 0.02-0.04 24-68 >20 0.03-0.05

C. Since the product works in an ultra-high voltage system, the mold must have a good exhaust system. The function is to smoothly discharge the original air in the cavity and the air generated during the molding process, so that the inner wall of the product There should be no air holes in the thick part, so as to avoid voltage breakdown during the use of the product;

D. The mold is required to ensure the accuracy of each dimension to avoid the failure of the sealing effect due to the phenomenon of flashing on the sealing end of the parting surface due to loose mold clamping, excessive clearance, insufficient clamping force, and excessive injection pressure. In addition, PA12 plastic It is especially important to adjust the injection molding process parameters when the molten material is highly fluid and prone to flashing.

Structural features:

The product must work in a closed water circulation system. According to the requirements of the system, the product must be able to withstand a test pressure of 1.0MPa without leakage. At the same time, the product must be able to withstand the sharp change in the temperature difference of 10-55°C in the system. Therefore, the utility model One of the key points is to choose a reliable sealing structure.

A. Both ends of the product are threaded, and the bottom of the thread at one end is equipped with a sealing groove. When in use, an O-ring can be installed to form a static external seal, which can effectively prevent leakage. The size of the sealing groove must fully consider the compression of the O-ring. The amount and relative sealing gap, the dimensional tolerance is controlled within the range of ±0.05mm;

B. The thread at this end can be directly installed and used with power electronic products and water transmission and distribution pipelines. Since the plastic is formed under pressure at a certain temperature, when it cools to room temperature, its size will shrink according to the principle of thermal expansion and contraction, and Most power electronic products are metal structures, and their threads are machined standard threads with a certain pitch. It is precisely because of the shrinkage of plastics that it is difficult to guarantee the pitch. Therefore, in the design and production process of the thread at this end, the thread must be able to separate from the The metal thread and the thread of plastic products are well matched;

C. The other end is M10 thread and the lock nut is connected together, and the hose sealing ring is squeezed axially through the locking force to form an inner sealing effect;

D. The interior is a through-hole structure, which has the characteristics of ultra-low water resistance loss. When the flow rate is 1-5L/min, the water resistance loss is 0.01-0.04bar.

Referring to Fig. 3, it is the lock nut 1 of the water-cooled connector of the present invention. The internal thread of the lock nut 1 cooperates with the rear end thread of the stud screw. When the inner bottom step and the top end face of the stud screw reach the locked state, the sealing step ring of the precision nylon water distribution conduit is squeezed to make the sealing ring axially uniformly deformed , forming the inner seal of the joint.

The lock nut is made of polyamide plastic (PA12). The processing method of mold injection molding is adopted.

Use a specific fixture to extrude two sealing step rings under the two ends of the precision nylon water distribution conduit through thermal processing, so that the lock nut is nested on the water distribution conduit, and the tolerance range of the outer diameter of the sealing ring is 0.1 to -0.05 mm, the thickness tolerance range is ±0.05mm.

processing method:

A. Take the symmetrical central plane of the product as the parting surface;

B. The internal thread uses the hexagonal end face as the anti-rotation mechanism, and the effect of automatic demoulding improves the production efficiency;

I. Calculation of large, medium and small diameters of threaded cores:

α—coordination coefficient value;

d(M, 1M, 2M) - thread diameter (mm);

D _{S, 1S, 2S} - the nominal size of the outer thread of the plastic part, the size of the large, small, and middle diameter;

Scp - the average shrinkage of the plastic used;

b——The large, small, and medium diameter tolerances corresponding to the threads of plastic parts, its values can refer to the metal thread tolerance standard GB197-81, and the lowest level of precision can be selected;

δ _z ——The manufacturing tolerance of the large, small and medium diameters corresponding to the thread, see Table 1-1.

II. For the calculation of thread core pitch, refer to formula 1-2.

C. The mold has a good exhaust system to prevent the occurrence of voltage breakdown during the use of air holes inside the product; structural features:

A. The lock nut is inserted into a certain length of precision nylon water distribution conduit (the conduit has passed the temperature rise-pressure test. When the temperature is 60°C, the burst pressure is ≥1.8Mpa; the tolerance of the inner and outer diameters of the pipe is within ±0.1mm. ; The service life is more than 25 years). Two sealing stepped rings are extruded under the nozzles at both ends by thermal processing through a specific fixture, so that the lock nut is nested on the hose. The outer diameter tolerance range of the sealing ring is 0.1 to -0.05mm, and the thickness tolerance range is ±0.05mm.

B. The inner thread of the lock nut cooperates with the thread of the rear end of the stud screw. When the inner bottom step and the top end face of the stud screw reach the locked state, the nylon conduit sealing ring is squeezed, so that the sealing ring is deformed by force in the axial direction, forming The inner seal of the joint.

Referring to Fig. 4, it is the O-ring 2 of the water-cooling connector. It is made of ethylene propylene diene monomer (EPDM) and processed by mold injection molding.

The hardness of the rubber is closely related to the working pressure of the seal. In order to achieve the static seal of the test pressure of 1MPa, the hardness of EPDM (Shore A)/degree is controlled at 60±5.

Structural features:

When in use, the sealing ring is elastically deformed by the thread locking force to form a static seal, and the tolerance range of the outer diameter is 0.08 to -0.04mm.

Referring to Fig. 5, it is the water distribution nut 5 of the water-cooling connector of the present invention. The water distribution nut 5 is cylindrical, the bottom is a concave spherical surface, and the internal through hole is hexagonal, and the thread is matched with the thread of the stud screw.

The water distribution nut is made of random copolymerized polypropylene (PPR), and is processed by mold injection molding.

Processing method: mold injection molding;

A. The profile is the parting surface;

B. The internal through hole is designed as a hexagonal end face as the anti-rotation mechanism, so that the internal thread can be automatically demolded and the production efficiency is improved;

C. The mold has a good exhaust system to prevent the occurrence of voltage breakdown during the use of the air holes inside the product.

Structural features:

A. The thread can cooperate well with the thread of the double-headed screw, and the sealing end surface is flat, so that the O-ring can achieve the sealing effect;

B. The spherical surface of the bottom is smooth, and the surface can be bonded with the PPR water distribution pipeline through the hot-melt fixture, and the pressure resistance is 1MPa within the temperature range of 10-55°C;

B. The diameter and height of the cylinder fully consider the spatial layout of the thyristor valve group structure, which can make the water transmission and distribution pipelines of the entire valve group easy to install, and reserve space for operation and maintenance.

Claims (2)

1, a kind of high-pressure high-power thyristor valve group water-cooled link is characterized in that: be made up of dowel screw, locking nut, water distribution conduit, O RunddichtringO, five parts of water distribution nut;

The dowel screw two ends are worm structure, and the threaded one end bottom is equipped with seal groove, and the O RunddichtringO wherein is installed, and forms static external sealed, prevents seepage effectively; The screw thread and the locking nut of the other end are connected, and its inside is through-hole structure; Locking nut is inserted in the accurate nylon water distribution conduit of certain-length; There are two sealed step rings the mouth of pipe below, two ends of water distribution conduit, thereby locking nut is nested on the water distribution conduit; Locking nut inner bottom part step and dowel screw top end face push accurate nylon water distribution conduit sealed step ring when reaching locking state, make the sealed step annulate shaft to even stress deformation, form the interior sealing of joint; The water distribution nut is cylindrical, and the bottom is interior concave spherical surface, and interior bone is the design of hexagon rotation preventive mechanism, the screw thread of water distribution nut and the screw-thread fit of dowel screw.

2, thyristor valve group water-cooled link according to claim 1 is characterized in that: dowel screw adopts Maranyl (PA12) to make; Locking nut adopts atactic copolymerized polypropene (PPR) to make; The O RunddichtringO adopts ethylene propylene diene rubber (EPDM) to make; The water distribution nut adopts atactic copolymerized polypropene (PPR) to make.

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