A vacuum powder sintering furnace special exhaust unit

Abstract

A kind of vacuum powder sintering furnace special evacuation unit, including diffusion pump, the diffusion pump is connected with front valve and main valve, and the connecting pipeline between diffusion pump and front valve is also provided with maintenance pump with maintenance valve;The end of the front valve away from diffusion pump is provided with three-way pipe, and the opening of three-way pipe away from diffusion pump is connected with pre-evacuation valve and front stage pump respectively;The end of the pre-evacuation valve away from three-way pipe is connected to main valve, and micro-evacuation valve is also provided between three-way pipe and main valve, the pre-evacuation valve and micro-evacuation valve cannot be opened simultaneously;Roots pump is arranged between three-way pipe and front stage pump, and rough evacuation valve is arranged between roots pump and front stage pump.Different from conventional equipment, the device is through multiple pipelines and is respectively provided with micro-evacuation valve, pre-evacuation valve and main valve, then control above-mentioned valve is opened in different time period, to be able to carry out vacuumizing operation in different stages for different purposes respectively.

Description

Technical Field

[0001] This utility model relates to the technical field of vacuum pumping units, specifically a vacuum pumping unit for vacuum powder sintering furnaces. Background Technology

[0002] Vacuum powder sintering technology involves treating metal / ceramic powders at high temperatures (typically 800-2000℃) in a vacuum (vacuum level on the order of 10⁻⁴) or protective atmosphere, promoting physicochemical reactions such as diffusion, flow, and recrystallization between powder particles to ultimately form a high-density, high-performance compact body. Its core advantages lie in its oxidation-free environment: the vacuum environment effectively eliminates oxide formation, ensuring material purity; microstructure control; more complete atomic diffusion under vacuum conditions; precise control of grain size and porosity; improved material mechanical properties (strength increased by 20%-40%, hardness optimized by 15%-25%); and process compatibility, as the introduction of protective gases such as hydrogen and argon allows for the integration of dewaxing, pre-firing, and sintering processes. However, during the initial vacuuming phase of a vacuum powder sintering furnace, a large amount of floating metal / ceramic powder remains inside the vacuum heating chamber. This powder not only contaminates the heaters, heat shields, and insulation components within the vacuum heating chamber but also enters the back pump, increasing equipment maintenance and production costs. Once the oil enters the backing pump, it will cause wear to the backing pump's rotor and valve plates, leading to a decrease in the backing pump's sealing performance during operation. This directly affects the vacuum pump's performance, eventually rendering the vacuum pump unusable. If the vacuum pump is not changed and cleaned in a timely manner, the operating performance of the evacuation unit will be affected, necessitating frequent oil changes for the vacuum pump. Utility Model Content

[0003] To address the issue that the presence of the aforementioned working fluid powder can affect the service life of the vacuum pump unit, this invention provides a dedicated vacuum pump unit for vacuum powder sintering furnaces.

[0004] The technical solution of this utility model is as follows:

[0005] A vacuum pumping unit for a vacuum powder sintering furnace includes a diffusion pump, which is connected to a pre-valve and a main valve, and a holding pump with a holding valve is also provided at the connection pipe between the diffusion pump and the pre-valve.

[0006] The end of the fore-stage valve away from the diffusion pump is provided with a three-way pipe, and the opening of the three-way pipe away from the diffusion pump is connected to the pre-extraction valve and the fore-stage pump respectively.

[0007] The pre-extraction valve is connected to the main valve at the end away from the tee pipe, and a micro-extraction valve is also provided between the tee pipe and the main valve. The pre-extraction valve and the micro-extraction valve cannot be opened at the same time.

[0008] A Roots pump is installed between the three-way pipe and the back pump, and a roughing valve is installed between the Roots pump and the back pump.

[0009] Unlike conventional equipment, this device uses multiple pipelines and is equipped with micro-vacuum valves, pre-vacuum valves, and main valves. By controlling the opening of these valves at different times, it can perform vacuuming operations at different stages for different purposes.

[0010] As a preferred embodiment, a gauge seat is provided between the pre-extraction valve and the tee pipe, and the micro-extraction valve is connected to the gauge seat.

[0011] To avoid affecting normal operations, the main valve cannot be opened simultaneously with the pre-extraction valve and the micro-extraction valve.

[0012] To ensure the proper functioning of the diffusion pump, the diffusion pump, the maintaining valve, and the maintaining pump are opened synchronously.

[0013] As a preferred embodiment, the vacuum level that triggers the closure of the micro-extraction valve is in the range of 10000Pa to 8000Pa.

[0014] To achieve rapid vacuuming, the vacuum level range for triggering the closure of the pre-vacuum valve is 100 Pa to 80 Pa.

[0015] To achieve a stronger vacuuming effect, the end of the coarse pump valve furthest from the Roots pump can be connected to multiple backing pumps simultaneously.

[0016] To facilitate venting, the tee is equipped with a vent pipe that can be opened and closed.

[0017] To facilitate external piping, the pipe connected to the maintaining valve at the end away from the maintaining pump is provided with an opening and closing port.

[0018] In order to prevent the working fluid powder from being extracted and to quickly achieve vacuuming, the opening time of the main valve cannot be earlier than that of the pre-vacuum valve, and the opening time of the pre-vacuum valve cannot be earlier than that of the micro-vacuum valve.

[0019] The beneficial effects of this utility model are as follows: This utility model is a special vacuum pumping unit for vacuum powder sintering furnaces. Unlike conventional vacuum pumping equipment, it divides the original vacuuming operation into three stages. In the first stage, by opening a micro-vacuum valve, it can effectively prevent the working fluid powder from being extracted in the initial stage, and can output clean air, effectively protecting the heating chamber and the forepump, extending the service life of the forepump, and reducing the maintenance cost of the equipment. This device is a three-stage vacuum unit composed of a diffusion pump, a Roots pump, and a slide valve pump. This vacuum unit has good pumping capacity from atmospheric pressure to 10-4 Pa. Then, a single-stage rotary vane holding pump with strong water vapor removal capacity and reliable operation under high pressure for a long time is selected as the forepump, reducing the number of times the forepump needs oil change and cleaning, and reducing production costs. Attached Figure Description

[0020] The advantages and solutions of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this invention.

[0021] In the attached diagram:

[0022] Figure 1 This is a front view structural diagram of the present invention;

[0023] Figure 2 This is a top view of the structure of this utility model;

[0024] Figure 3 This is a partial structural diagram of the present invention;

[0025] The components represented by the various reference numerals in the diagram are:

[0026] 1. Backing pump; 2. Coarse extraction valve; 3. Roots pump; 4. Backing valve; 5. Pre-extraction valve; 6. Micro-extraction valve; 7. Diffusion pump; 8. Holding valve; 9. Holding pump; 10. Main valve; 11. Gauge seat. Detailed Implementation

[0027] Example

[0028] like Figure 1 , 2 The vacuum pumping unit shown includes a diffusion pump 7, which is connected to a pre-valve 4 and a main valve 10. By opening different valves, different pumps can function at different stages and produce corresponding effects. It should be noted that a holding pump 9 with a holding valve 8 is also provided at the connection pipe between the diffusion pump 7 and the pre-valve 4. In order to ensure the normal use of the diffusion pump 7, the diffusion pump 7, the holding valve 8, and the holding pump 9 are opened synchronously. The holding pump 9 is a mechanical pump, while the holding valve 8 is a solenoid valve, which facilitates synchronous opening. In this way, the diffusion pump 7 can be started and stopped.

[0029] Subsequently, in order to enable different pumps to perform different functions under different vacuum levels, a three-way pipe is provided at the end of the fore-stage valve 4 away from the diffusion pump 7, and the opening of the three-way pipe away from the diffusion pump 7 is connected to the pre-evacuation valve 5 and the fore-stage pump 1 respectively. The pre-evacuation valve 5 can control the opening and closing of the above-mentioned pipeline, and when it is closed, it can enable the fore-stage valve 4 to function. By switching the different opening and closing states of the fore-stage valve 4 and the pre-evacuation valve 5, vacuuming operations can be performed with different vacuuming capabilities.

[0030] It should be noted that the end of the pre-extraction valve 5 furthest from the tee pipe is connected to the main valve 10, and a micro-extraction valve 6 is also provided between the tee pipe and the main valve 10. The diameter of the pipe where the micro-extraction valve 6 is located is smaller than the diameter of the pipe connecting the pre-extraction valve 5 and the main valve 1. Therefore, under the same conditions, the micro-extraction valve 6 can perform a different effect than the pre-extraction valve 5. The ratio of the diameter of the pipe where the micro-extraction valve 5 is located to the diameter of the pipe where the pre-extraction valve 5 is located is less than 1 / 5. It should also be noted that the pre-extraction valve 5 and the micro-extraction valve 6 cannot be opened simultaneously. When one is open, the other needs to be closed. Different functions can be achieved by switching the valve bodies as described above. Afterwards, in order to avoid affecting normal operation, the main valve 10 cannot be opened simultaneously with the pre-extraction valve 5 and the micro-extraction valve 6.

[0031] Furthermore, regarding the aforementioned situation, the vacuum level range for triggering the closure of the micro-vacuum valve 6 is 10000 Pa to 8000 Pa. To achieve rapid vacuuming, the vacuum level range for triggering the closure of the pre-vacuum valve 5 is 100 Pa to 80 Pa. Specifically, to prevent the metal / ceramic powder (working fluid powder) from being drawn away, the system is equipped with a micro-vacuum valve 6, which has a pressure-releasing coarse evacuation function. Initially, the micro-vacuum valve 6 is opened to evacuate the vacuum chamber. When the vacuum level reaches 10000 Pa to 8000 Pa, the micro-vacuum valve 6 is closed, and the pre-vacuum valve 5 is opened to evacuate the vacuum chamber. When the vacuum level reaches 100 Pa to 10 Pa, the pre-vacuum valve 5 is closed, and the main valve 1 is opened to evacuate the vacuum chamber until the vacuum level reaches the order of 10⁻⁴ Pa.

[0032] Subsequently, in order to ensure that the vacuuming operation can be carried out quickly after the main valve 1 is opened, a Roots pump 3 is installed between the three-way pipe and the back pump 1, and a roughing valve 2 is installed between the Roots pump 3 and the back pump 1.

[0033] The above structure enables vacuuming operations to be performed at different stages for different purposes, unlike conventional equipment. This device uses multiple pipelines and is equipped with micro-vacuum valve 6, pre-vacuum valve 5 and main valve 10 respectively. The valves are then controlled to open at different times, thereby achieving different effects at different stages. In order to avoid equipment damage, the above vacuum valves are all pneumatic baffle structures. In the event of a sudden power failure, all pneumatic valves will close automatically to protect the system from damage.

[0034] In a preferred embodiment, a gauge seat 11 is provided between the pre-extraction valve 5 and the three-way pipe, and the micro-extraction valve 6 is connected to the gauge seat 11.

[0035] To achieve a stronger vacuuming effect, the end of the coarse pumping valve 2 furthest from the Roots pump 3 can be connected to multiple backing pumps 1 simultaneously. If necessary, vacuuming can be performed by simultaneously turning on multiple backing pumps 1. However, multiple backing pumps 1 can only be turned on simultaneously when the main valve 1 is open. When the micro pumping valve 6 or the pre-pumping valve 5 is open, only a single backing pump 1 can operate. In other words, the switch that controls the simultaneous opening of multiple backing pumps 1 needs to be referenced to the opening of the main valve 1.

[0036] Subsequently, to facilitate venting, the three-way pipe is equipped with a vent pipe that can be opened and closed.

[0037] To facilitate external piping, the pipe connected to the end of the maintaining valve 8 away from the maintaining pump 9 is provided with an openable and closable connection port, through which various pumps or other equipment can be connected to facilitate the functional adjustment of the overall system.

[0038] Finally, the design is tailored to the application scenario. To prevent the working fluid powder from being extracted and to quickly achieve vacuuming, the opening time of the main valve 10 cannot be earlier than that of the pre-vacuum valve 5, and the opening time of the pre-vacuum valve 5 cannot be earlier than that of the micro-vacuum valve 6.

Claims

1. A vacuum pumping unit specifically for a vacuum powder sintering furnace, characterized in that, Includes a diffusion pump (7), which is connected to a pre-stage valve (4) and a main valve (10), and a maintenance pump (9) with a maintenance valve (8) is also provided at the connection pipe between the diffusion pump (7) and the pre-stage valve (4). The end of the pre-stage valve (4) away from the diffusion pump (7) is provided with a three-way pipe, and the opening of the three-way pipe away from the diffusion pump (7) is connected to the pre-extraction valve (5) and the pre-stage pump (1) respectively. The pre-extraction valve (5) is connected to the main valve (10) at the end away from the three-way pipe, and a micro-extraction valve (6) is also provided between the three-way pipe and the main valve (10). The pre-extraction valve (5) and the micro-extraction valve (6) cannot be opened at the same time. A Roots pump (3) is installed between the three-way pipe and the back pump (1), and a coarse pumping valve (2) is installed between the Roots pump (3) and the back pump (1).

2. The vacuum pumping unit for a vacuum powder sintering furnace according to claim 1, characterized in that, A gauge seat (11) is provided between the pre-extraction valve (5) and the three-way pipe, and the micro-extraction valve (6) is connected to the gauge seat (11).

3. The vacuum pumping unit for a vacuum powder sintering furnace according to claim 1, characterized in that, The main valve (10) cannot be opened simultaneously with the pre-extraction valve (5) and the micro-extraction valve (6).

4. The vacuum pumping unit for a vacuum powder sintering furnace according to claim 1, characterized in that, The diffusion pump (7) is turned on synchronously with the holding valve (8) and the holding pump (9).

5. The vacuum pumping unit for a vacuum powder sintering furnace according to claim 1, characterized in that, The vacuum range that triggers the closure of the micro-extraction valve (6) is 10000Pa to 8000Pa.

6. The vacuum pumping unit for a vacuum powder sintering furnace according to claim 1, characterized in that, The vacuum range that triggers the closure of the pre-evacuation valve (5) is 100 Pa to 80 Pa.

7. The vacuum pumping unit for a vacuum powder sintering furnace according to claim 1, characterized in that, The end of the coarse extraction valve (2) away from the Roots pump (3) can be connected to multiple backing pumps (1) at the same time.

8. The vacuum pumping unit for a vacuum powder sintering furnace according to claim 1, characterized in that, The tee pipe is equipped with a vent pipe that can be opened and closed.

9. The vacuum pumping unit for a vacuum powder sintering furnace according to claim 1, characterized in that, The maintaining valve (8) is provided with a connecting port that can be opened and closed at the end of the pipe connected to it away from the maintaining pump (9).

10. A vacuum pumping unit for a vacuum powder sintering furnace according to claim 1, characterized in that, The opening time of the main valve (10) cannot be earlier than that of the pre-extraction valve (5), and the opening time of the pre-extraction valve (5) cannot be earlier than that of the micro-extraction valve (6).

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