CN100560230C - Cleaning system for adhesives used in a new method of microwave tube slow wave circuit bonding assembly - Google Patents

Abstract

The invention discloses a cleaning system for an adhesive used in a new method for bonding and assembling a microwave tube slow-wave circuit. The cleaning system of the present invention can not only thoroughly clean away the adhesive, but also fully save the cleaning solvent, has a simple structure, can operate continuously, is convenient, flexible, safe and reliable. The cleaning system of the present invention is a continuous cycle system in which the cleaning medium is evaporated, condensed, and re-evaporated by using separate heat pipes, and the cleaning fixture is connected in series in the condensate return circuit.

Description

Cleaning system for adhesives used in a new method of microwave tube slow wave circuit bonding assembly

technical field

The invention relates to a cleaning system, in particular to a cleaning system for adhesives used in a new method of bonding and assembling microwave tube slow-wave circuits.

Background technique

At present, most domestic microwave tube slow-wave circuit assembly adopts mechanical methods such as elastic deformation clamping assembly method or expansion clamping assembly method, but this method will greatly limit the high-frequency characteristics of microwave tubes, thereby also limiting the power of small and medium power microwaves in my country. Tube manufacturing level.

In order to improve the high-frequency characteristics of microwave tubes, thereby improving the manufacturing level of my country's small and medium-power microwave tubes, it is imperative to develop a new process for assembling microwave tube slow-wave circuits. A new method of slow-wave circuit bonding assembly, and developed its related assembly bonding fixture and adhesive cleaning system. It is required that the assembly bonding fixture should ensure uniform contact between the clamping rod and the helix and ensure that the clamping rod is accurate. positioned on the helix. In addition, this assembly method requires that the adhesive must be completely removed at the end to ensure the normal operation of the microwave tube, and the method of removing the adhesive is the burning method in addition to the cleaning method. Since the microwave tube device cannot be burned in an oxygen atmosphere, it can only be changed. Using the hydrogen burning method, the experiment proves that the hydrogen burning method cannot completely remove the adhesive, so the solvent cleaning method is ideal, and the present invention has developed a binder cleaning system.

Contents of the invention

The purpose of the present invention is to solve the problems and deficiencies in the prior art. It provides a system for cleaning the adhesive used in the new method of bonding and assembling microwave tube slow-wave circuits. The system can completely remove the adhesive used.

The present invention is achieved through the following technical solutions:

The adhesive cleaning system used in the new method of microwave tube slow-wave circuit bonding assembly of the present invention is a continuous cycle system in which the cleaning medium is evaporated, condensed, and re-evaporated by using a separate heat pipe, and the cleaning fixture is connected in series in the condensate return line. The cleaning system described therein includes a drain valve, a heating container with a separate heat pipe, a cleaning liquid inlet, a clamp-type quick-fit flange, a pressure gauge, a vent valve, a flow meter, a cleaning fixture, and a cleaning fixture with a separate heat pipe. The upper end of the heating vessel is connected to the jacketed condenser through the steam pipeline, and the jacketed condenser is connected to the cleaning fixture through the condensing pipeline, and the cleaning fixture is connected to the lower end of the heating vessel with a separate heat pipe through the pipeline. A vent valve is installed before the inlet of the jacket condenser, a flow meter is installed between the jacket condenser and the cleaning fixture, and a flow meter is also installed between the cleaning fixture and the heating container with a separate heat pipe. The lower part of the heating container is also provided with a drain valve, and the upper part is provided with a cleaning liquid inlet; the cleaning fixture is a cylindrical structure, which is composed of a cleaning liquid inlet chamber, a cleaning chamber and a cleaning liquid outlet chamber connected in sequence, and the inner diameter of the inlet chamber is smaller than that of the cleaning chamber. , the inner diameter of the outlet port of the inlet chamber is smaller than the inner diameter of the inlet chamber, the inner diameter of the two ports of the cleaning chamber is smaller than the inner diameter of the cleaning chamber, the inner diameter of the outlet chamber is larger than the inner diameter of the cleaning chamber, the liquid inlet port in the cleaning chamber is equipped with a sealing ring, and the outlet chamber is equipped with a core rod baffle and microwave tube set bolts.

The beneficial effects of the present invention are:

After the microwave tube is assembled, the adhesive can be completely removed to ensure the normal operation of the microwave tube. The adhesive cleaning system can not only clean the adhesive thoroughly, but also fully save the cleaning solvent. It has a simple structure and continuous operation. It is convenient, flexible, safe and reliable, so that the assembled microwave tube slow-wave circuit can greatly improve the high-frequency characteristics of the microwave tube.

Description of drawings

Figure 1 Schematic diagram of the cross-sectional structure of the microwave tube

Figure 2 Schematic diagram of the requirements for cooperation between the clamping rod and the helix

Figure 3 Schematic diagram of the action section of the clamping rod positioning beam

Figure 4 Schematic diagram of clamping rod positioning beam function

Figure 5 Schematic diagram of the overall assembly and positioning of the clamping rod and the helix

Figure 6 Schematic diagram of the working principle of the separated heat pipe

Figure 7 Schematic diagram of the cleaning system with the cleaning fixture placed horizontally

Figure 8 Schematic diagram of the cleaning system with the cleaning fixture placed vertically

Figure 9 Schematic diagram of the structure of the microwave tube cleaning fixture

Description of each part in the figure:

1. Microwave tube shell, 2. Molybdenum helix, 3. Ceramic clamping rod, 4. Uniform load, 5. Beam, 6. Tungsten core rod, 7. Hexagonal main positioning block, 8. Wrapped with molybdenum Helical tungsten core rod, 9. Positioning hole, 10. Positioning bolt, 11. Input heat, 12. Working fluid, 13. Working fluid evaporates into steam, 14. Steam is condensed into working fluid, 15. Output heat, 16. Drain valve, 17. Heating vessel with separate heat pipe, 18. Cleaning liquid inlet, 19. Clamp type quick-fit flange, 20. Pressure gauge, 21. Vent valve, 22. Jacket condensation, 23. Flow meter , 24. Cleaning fixture, 25. Cleaning liquid inlet bin, 26. Inlet bin outlet port, 27. Seal ring, 28. Cleaning bin, 29. Microwave tube assembly, 30. Microwave tube positioning bolt, 31 Cleaning liquid outlet bin , 32. Core rod baffle, 33. Cleaning fluid flow direction

Detailed ways

Example 1

The new method of bonding and assembling microwave tube slow wave circuit of the present invention has the following steps:

a) First, accurately position the three clamping rods on the helix with the core rod at an angle of 120 degrees, and then apply adhesive to bond the clamping rod and the helix. Molding agent, the beam is a rectangular inner groove structure with a taper angle, the upper inner groove is an inverted T-shaped groove, the clamping rod is embedded below the taper angle, and then the positioning agent is applied in the groove of the beam, and then the The axis of the core rod is accurately positioned on the axis of the main positioning block. There are two main positioning blocks, which are regular hexagonal structural parts. Six positioning holes are uniformly arranged around each main positioning block. Two main positioning blocks It is fixed by 6 steel rods closely matched with the positioning holes, and the distance between them depends on the length of the clamping rod; the two sides of the main positioning block are respectively provided with the same precision requirements. The positioning block is exactly the same as the regular hexagonal plate, the thickness is 2mm, and the distribution of the surrounding positioning holes is also the same as that of the main positioning block. There is a hole in the center of the axis positioning block. The size of the hole is such that the core rod can be inserted into the hole. The regular hexagonal structural part of the main positioning block is processed by the overall wire cutting method. The cutting step value of the wire cutting equipment is 1 micron, and the precision is controlled within 10 ^-4 mm. set bolts evenly spaced at an angle of 120 degrees. Finally, insert the three beams embedded with the clamping rods into the middle of the two main positioning blocks at an angle of 120 degrees, and enter the T-shaped slots through the positioning bolts. Press the clamping rod towards the center of the shaft. Then install three clamping rods respectively, assemble the three beams embedded with the clamping rods on the fixture with the core rod and the helix to form a combination, and then apply adhesive to bond the clamping rod and the helix. After the glue is completely cured, remove the fixture and remove the positioning agent, so that the three clamping rods are evenly distributed on the helix in the circumferential direction of 120°,

b) After the adhesive is cured, grind three clamping rods according to the size to make a clamping rod-core rod-helix assembly;

c), vertically pull the prepared clamping rod-core rod-helix assembly and the microwave tube into the microwave tube shell under interference fit;

d) Clean off the adhesive bonding the clamping rod and the helix, and the microwave tube slow wave circuit is assembled successfully.

The assembly target of the microwave tube is shown in Figure 1. By using the close cooperation between the ceramic clamping rod 3 and the microwave tube shell 1 and the molybdenum helix 2, the microwave tube, the ceramic clamping rod 3 and the molybdenum helix 2 are realized. During manufacture, the ceramic clamping rod 3 and the molybdenum helix 2 are first accurately positioned, and then the adhesive is applied. The contact between the ceramic clamping rod 3 and the molybdenum helix 2 is required to be uniform, that is, every The ceramic clamping rod 3 is in contact with the molybdenum helix 2 every week. The ceramic clamping rod 3 is a thin filament with a section of 1.0×0.5mm, and the overall rigidity is small, so the ceramic clamping rod 3 must be fixed. Only when the clamping rod 3 is applied with a uniform load can the uniform contact between the ceramic clamping rod 3 and the molybdenum helix 2 be achieved, as shown in Figure 2, in order to achieve a good Contact, the ceramic clamping rod 3 is placed on a straight beam 5, the beam 5 is a rectangular inner groove structure with a taper angle, the upper inner groove is an inverted T-shaped groove, and the clamping rod 3 is embedded Below the taper angle, the structure of the beam 5 is shown in Figure 3 and Figure 4. The base material of the beam 5 is Cr12, a high-hardness and high-strength material. Wire cutting is used to achieve the straightness and precision of the beam. In the structural design of the beam Increase the stiffness of the beam as much as possible, especially the stiffness in the axial direction, to ensure the uniform contact between the clamping rod 3 and the molybdenum helix 2. The stress calculation of the material can be used to confirm that the designed beam is under a certain compression force. Under certain conditions, the elastic deformation of the molybdenum helix 2 can be matched to ensure uniform contact between the clamping rod 3 and the molybdenum helix 2 . In addition to sufficient requirements for the contact between the ceramic clamping rod 3 and the molybdenum helix 2, it is also required that the three ceramic clamping rods 3 be evenly distributed in the circumferential direction, because the outer diameter of the molybdenum helix 2 is small, so in When positioning, a slight deviation will cause the ceramic clamping rod 3 to deviate from the center plane of the molybdenum helix 2. This will not only ensure the uniform distribution of the ceramic clamping rod 3, but also cause the ceramic clamping rod 3 to 3 and the poor contact between the molybdenum helical wire 2, so it is necessary to ensure that the position of the ceramic clamping rod 3 is accurate; for this reason, the present invention has designed a hexagonal main positioning block 7 that positions the three beams as a whole, as shown in Figure 5. There are 2 main positioning blocks, which are regular hexagonal structural parts, and 6 positioning holes 9 are uniformly arranged around each main positioning block, and the two main positioning blocks pass 6 steel rods closely matched with the positioning holes 9 The spacing depends on the length of the ceramic clamping rod; the main positioning block 7 adopts the overall wire cutting method for one-time processing, the cutting step value of the wire cutting equipment is 1 micron, and the precision control is 10 ^-4 mm. Through calculation and Experiments confirm that this processing method can ensure the assembly requirements of the clamping rod 3, and the two sides of the main positioning block 7 are respectively provided with axis positioning blocks with the same precision requirements. Edge-shaped plate with a thickness of 2mm, the distribution of the surrounding positioning holes is also the same as that of the main positioning block, and the axis is provided with a positioning hole that can be closely matched with the core rod.

The straightness problem of the ceramic clamping rod 3 can be solved by adopting the embedded rigid beam of the ceramic clamping rod 3, but similarly, the molybdenum helix 2 must also have the requirement that the outer circle of the helix 2 also has the requirement of axis positioning. There must be a requirement of straightness, so as to meet the requirements for matching with the clamping rod 3. A tungsten core rod 6 is set on the inner side of the spiral. The outer circle of the tungsten core rod 6 is precisely ground, with a diameter of 2.90mm. The total length is 180mm. For such a core rod, the rigidity of itself is not high. It is very difficult to fully utilize the core rod to ensure the straightness of the outer circular surface of the molybdenum helix 2; Axis center positioning blocks with the same precision requirements are respectively set on both sides, and the axis of the tungsten core rod 6 is accurately positioned first, and then the beam is pressed from three directions of 120 degrees to the axis of the clamping rod 3. Under the restriction of the positioning block, the positions of the two ends of the tungsten core rod 6 are fixed. At this time, the stress of the tungsten core rod 6 is a simply supported beam, and the force deformation near the fulcrum is very small, so when the beam and ceramics are clamped The position of the two ends of the rod 3 near the axis positioning block is relatively accurate, and the beam embedded in the ceramic clamping rod 3 has a high straightness, so the overall position of the ceramic clamping rod 3 is accurately positioned; at the same time, The ceramic clamping rod 3 is pressed toward the axis from three evenly distributed directions, just like the three-jaw clamp on the lathe, the molybdenum helix 2 is positioned at the center position accurately, that is, the ceramic clamping rod 3 to define the position of the molybdenum helix 2, which not only ensures good contact between the ceramic clamping rod 3 and the molybdenum helix 2, but also ensures the contact between the ceramic clamping rod 3 and the helix 2. location accuracy.

The cleaning system of the present invention utilizes the design principle of the separated heat pipe to realize the continuous operation of the system under negative pressure, that is, the cleaning device is designed as a separated heat pipe, and the working principle of the heat pipe can be used to realize the continuous operation of the system under the condition of an absolute pressure of 0.01Mpa. Run and clean. The separated heat pipe is a high-efficiency heat transfer element, which is widely used in various heat transfer processes. Its simple working principle is: a certain working medium is filled in a closed vacuum system, and heat is input at the evaporation end of the heat pipe during operation. The working medium at the evaporating end is vaporized after being heated, and the working medium steam that has absorbed the latent heat of vaporization enters the condensing end through the pipe, where heat is released, the steam condenses into a liquid, and the condensate flows back to the evaporating end through the return pipe, thus forming a continuous cycle , form the continuous transmission of heat from the evaporation end to the condensation end, as shown in Figure 6; the cleaning system in the present invention is not to realize the transmission of heat, but mainly to clean the microwave tube assembly by using the continuously circulating working medium in the heat pipe , that is, the evaporated and purified working medium is refluxed after condensation, and flows through the microwave tube assembly during the reflux process to clean the adhesive on the microwave tube assembly. At the same time, because it is a vacuum system, the working medium can be vaporized under negative pressure, and continuous processes such as vaporization and condensation can be realized. In this way, the microwave tube assembly can also be cleaned under negative pressure. Working medium and adhesive are very useful. This embodiment can realize continuous cleaning under the absolute pressure of 0.01Mpa-2Mpa.

As shown in Figure 7, the cleaning system of the present invention includes a drain valve 16, a heating container 17 with a separate heat pipe, a cleaning liquid inlet 18, a clamp type quick-fit flange 19, a pressure gauge 20, a vent valve 21, a flow rate Meter 23, cleaning jig 24, the upper end of the heating container 17 with separate heat pipes is connected to the jacket condenser 22 through a steam pipeline, and the jacket condenser 22 is connected to the cleaning jig 24 through a condensing pipeline, and the cleaning jig 24 is connected through a pipeline The lower end of the heating vessel 17 with a separate heat pipe, the steam pipe is equipped with a pressure gauge, the jacket condenser 22 is equipped with a vent valve before the inlet, and a flow meter is installed between the jacket condenser and the cleaning fixture, and the cleaning fixture and the A flow meter is also installed between the heating containers of the separated heat pipes, a drain valve 16 is provided at the bottom of the heating container with the separated heat pipes, and a cleaning liquid inlet 18 is provided at the top.

As shown in Figure 9, a cleaning jig 24 is specially designed according to the actual structure (thin and long inner cavity) and size of the microwave tube. The inner diameter of the liquid outlet chamber 31 is smaller than the inner diameter of the inlet chamber 25, the inner diameter of the inlet chamber 26 is smaller than the inner diameter of the inlet chamber 25, the inner diameter of the two ports of the cleaning chamber is smaller than the inner diameter of the cleaning chamber 28, and the inner diameter of the cleaning liquid outlet chamber 31 is larger than that of the cleaning chamber 28 internal diameters, the liquid inlet port in the cleaning chamber 28 is equipped with a sealing ring, and the core rod baffle plate 32 and the microwave tube positioning bolt 30 are housed in the outlet chamber. The fixture ensures that the cleaning liquid must flow through the part where the adhesive exists, and at the same time effectively positions the assembly during the cleaning process to prevent the ceramic clamping rod 3 and the molybdenum helix 2 from being washed out by the cleaning liquid during the cleaning process. the movement of the cleaning fixture; the cleaning fixture is horizontally connected in the condensate return line in series, as shown in Figure 7, according to the actual cleaning needs, a heating or cooling or even a freezing device is installed on the return line and the cleaning fixture to effectively control the temperature of the microwave tube. Cleaning temperature; in this embodiment, the adjustment of the heating amount (i.e. the input heat at the evaporation end) can realize the adjustment of the total evaporation amount. At the condensation end, the water cooling area in this embodiment can be adjusted, so by cooling The adjustment of the area can adjust the output heat of the condensation end to ensure that the evaporated working medium vapor can be completely cooled, thereby realizing the adjustment of the amount of cleaning liquid. In the liquid return circuit of this embodiment, a rotameter and a liquid level gauge are also provided, which can accurately measure the flow rate of the cleaning liquid and enhance the characterization of the cleaning process.

This embodiment is under pressure during operation, and is carried out according to the requirements of the pressure vessel during the design and manufacture process. After the manufacture, the pressure test and air tightness test are carried out as required. The system is equipped with a pressure gauge, a safety explosion-proof membrane and an emergency vent. etc., to ensure safe operation during the test process and cleaning process.

This embodiment adopts a built-in heating structure, and the heating at the evaporation end adopts an internally inserted heating element, which has fast heating speed, high efficiency, good safety, small thermal inertia, fast and effective control of the heating process, and simple structural layout.

In this embodiment, the connection part adopts a clamp-type quick-installation flange, which can facilitate the loading and unloading of the cleaning fixture, and it is very convenient to replace the cleaned microwave tube assembly.

The technological conditions for cleaning and bonding the adhesive used for assembling microwave tubes in this embodiment are as follows: the cleaning solvent is butanone, the cleaning temperature is about 80° C., the pressure is about 0.2 kg, and the flow rate of the cleaning agent flowing through the test piece is 3.5 L/h , the cleaning time is 1 hour, pay attention to the non-condensable gas must be discharged during the cleaning and heating process.

Example 2

The method and process are the same as in Example 1, except that the cleaning jig 24 is placed vertically as shown in Figure 8. When placed vertically, the flow direction of the cleaning liquid is vertically downward, and the liquid flushing direction is consistent with the direction of gravity, and the flushing effect is better. However, the direction of the scouring force on the inner core component of the microwave tube is also consistent with the direction of gravity. During the flushing process, the inner core may be washed away from the assembly position, causing flushing to be scrapped; while flushing in a horizontal position, the direction of liquid flushing and the direction of gravity The washing effect is worse than that of the vertical position, but the washing force of the microwave tube core assembly is perpendicular to the direction of gravity, and it is relatively difficult to wash away from the assembly position. These two methods can be easily switched as needed.

Claims (1)

1. A cleaning system for the adhesive used in the new method of microwave tube slow-wave circuit bonding assembly, characterized in that the cleaning system is a continuous cycle system that uses separate heat pipes to evaporate, condense, and re-evaporate the cleaning medium, and the cleaning fixtures are connected in series In the condensate return line, the cleaning system includes a drain valve, a heating container with a separate heat pipe, a cleaning liquid inlet, a clamp-type quick-fit flange, a pressure gauge, a vent valve, a flow meter, and a cleaning fixture And the jacket condenser, the upper end of the heating vessel with a separate heat pipe is connected to the jacket condenser through a steam pipe, and the jacket condenser is connected to the cleaning fixture through a condensation pipe, and the cleaning fixture is connected to a separate heat pipe through a pipe. At the lower end of the heating vessel, a pressure gauge is installed on the steam pipe, a vent valve is installed before the inlet of the jacketed condenser, a flow meter is installed between the jacketed condenser and the cleaning fixture, and between the cleaning fixture and the heating vessel with a separate heat pipe It is also equipped with a flow meter, and the lower part of the heating container with a separate heat pipe is also provided with a drain valve, and the upper part is provided with a cleaning liquid inlet; The inner diameter of the inlet chamber is smaller than the inner diameter of the cleaning chamber, the inner diameter of the outlet port of the inlet chamber is smaller than the inner diameter of the inlet chamber, the inner diameter of the two ports of the cleaning chamber is smaller than the inner diameter of the cleaning chamber, the inner diameter of the outlet chamber is larger than the inner diameter of the cleaning chamber, and the liquid inlet port in the cleaning chamber is installed. There is a sealing ring, and the outlet chamber is equipped with a core rod baffle and a microwave tube positioning bolt.

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