JPH03105190A - Leak device in vacuum drying device - Google Patents

Abstract

PURPOSE:To minimize the inflow of atmosphere upon switching between communication and interception and prevent the reverse flow of oil due to malfunction by a method wherein a vacuum pump is connected to a vacuum drying chamber and the communication as well as the interception are effected by the fluid ports of a three-way ball valve in two directions while the remaining fluid port is provided with a plug equipped with a capillary. CONSTITUTION:A two-way valve 27 is connected to a pipeline 25 on the back wall of a frame 9 while a pipeline 29 is connected to the two-way valve 27 whereby the pipeline 25 is opened to a atmosphere or connected to an inert gas supplying device 31. One end of another pipeline 33 is connected to the back wall of the frame 9 and a three-way ball valve 35 is connected to the pipeline 33. An external vacuum pump 39 is connected to the three-way ball valve 35 and one end of a plug 43 equipped with a capillary 41 is connected to the remaining fluid port of the valve 35 while the other end of the capillary 41 is opened to atmosphere. The two-way valve 27 is switched to intercept the pipeline 25 from the pipeline 29, the three-way ball valve 35 is switched to communicate the pipeline 33 with the pipeline 37, the vacuum pump 39 is operated and the inside of a vacuum drying chamber 7 is brought into vacuum condition to effect the vacuum drying process of a substance to be measured in the vacuum drying chamber 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a leak device in a vacuum drying apparatus.

<Prior Art> Conventionally, in order to evacuate the vacuum drying chamber of a vacuum drying apparatus, a vacuum bomb is attached to the rear wall of the vacuum drying chamber via piping. A stop valve is provided in the middle of this piping. To evacuate the vacuum drying chamber, a stop valve is opened and a vacuum bomb is activated to evacuate the vacuum drying chamber.

(Problems to be Solved by the Invention) By the way, in the above-mentioned conventional technology, in order to maintain the vacuum drying chamber under predetermined conditions, it is first necessary to manually close the stop valve and prevent backflow of the oil in the vacuum bomb. There was a problem in that three operations were required: removing the piping between the stop valve and the vacuum bomb, and then turning off the power to the vacuum pump, which was very troublesome.

In order to solve the above problem, it is possible to use a three-way solenoid valve instead of a stop valve to automatically return the vacuum pump side to atmospheric pressure and prevent oil backflow, but a vacuum pump with a small displacement is used. In vacuum drying equipment, which is used frequently, three-way solenoid valves with large internal diameters are generally not used because they are expensive, although it is necessary to reduce the resistance in the piping as much as possible.

In addition, if a cheap one-way ball valve is simply used instead of a stop valve, when a three-way ball valve is used to connect and cut off communication, the vacuum drying chamber and the atmosphere will inevitably flow in the middle, resulting in a leak in the vacuum drying chamber. There was a problem in that the degree of vacuum was lowered, and it took a long time to restore the degree of vacuum to its original state.

The purpose of this invention is to improve the above-mentioned problems by providing a one-way ball valve in the middle of the piping connecting the vacuum drying chamber and the vacuum bomb, and preventing the inflow of atmospheric air when switching the three-way ball valve between communication and isolation. It is an object of the present invention to provide a leak device for a vacuum drying apparatus which suppresses the degree of vacuum to a minimum and prevents the degree of vacuum from decreasing excessively, and which prevents backflow of oil due to erroneous operation.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention connects a vacuum pump to the vacuum drying chamber via piping in order to evacuate the vacuum drying chamber in a vacuum drying apparatus. A three-way ball valve is installed in the middle of the ship's piping, and the two-way fluid ports of this three-way ball valve are used to connect and shut off the piping, and the remaining one-way fluid port is connected to a capillary that communicates with the atmosphere. A leak device in a vacuum drying apparatus was constructed by providing a plug with a

Further, in the leak device of the vacuum drying apparatus, the present invention includes a drive device for automatically switching the three-way ball valve, and the vacuum bomb is interlocked and connected to the drive device via a control element. This is how it was done.

(Function) By employing the leak device in the vacuum drying apparatus of the present invention, the vacuum drying chamber is evacuated by operating the vacuum bomb and switching the three-way ball valve to evacuate. When the vacuum drying chamber reaches a predetermined degree of vacuum, the degree of vacuum is maintained by constantly switching off the three-way ball valve, and at the same time, the vacuum bomb is opened to the atmosphere, so the power to the vacuum pump can be turned off at any time.

When the three-way ball valve is switched from "communicating" to "blocking", the vacuum drying chamber may be communicated with the atmosphere, causing a leak, but one fluid port of the three-way ball valve is provided with a plug equipped with a capillary. Therefore, the amount of leakage is minimized, and the degree of vacuum in the vacuum drying chamber is not lowered to the Fi end, and only a small amount of leakage is required.

Furthermore, since the three-way ball valve is switched by the drive device and the vacuum bomb is automatically stopped via the control device, backflow of oil due to erroneous operation is prevented and erroneous operation is eliminated.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Referring to FIG. 1, the vacuum drying apparatus 1 consists of a vacuum drying chamber main body 3 and a device N5 that can be opened and closed on the front of the vacuum drying chamber main body 3. It consists of an inner frame 9 having a vacuum drying chamber 7 for storing objects, and an outer frame 13 covering the outside of the inner frame 9 with a heat insulating material 11 in between. A heater 15 is provided to heat the drying chamber 7 to a constant temperature.

For example, a rectangular opening 1 is provided on the front surface of the inner frame 9.
7 is formed, and a packing 19 made of rubber or the like is provided on the front surface of the inner frame 9 at the outer periphery of the opening 17.
is installed.

The door 5 includes a transparent glass plate 21 provided at a position corresponding to the opening 17, and this glass plate 21.
The door frame 23 supports and covers the door frame 23.

With the above structure, the operator opens the door 5 to accommodate the object to be measured in the vacuum drying chamber 7 of the vacuum drying chamber main body 3, and then closes the door 5. By evacuating the vacuum drying chamber 7 and controlling the temperature to a constant temperature by heating with the heater 15, the object to be measured can be vacuum dried under desired conditions.

When the object to be measured is being vacuum-dried in the vacuum drying chamber 7, the state of the object to be measured can be checked by passing it through the transparent glass plate 21<1! can be understood.

One end of a pipe 25 is connected to the rear wall of the internal frame 9, and the other end of the pipe 25 is connected to a two-way valve 27. One end of a pipe 29 is connected to this two-way valve 27, and the other end of this pipe 29 is either exposed to the atmosphere by protruding the outer frame 13, or is supplied with an external inert gas such as N2 gas. It is connected to the device 31.

One end of a pipe 33 other than the pipe 29 is connected to the rear wall of the inner frame 9, and the other end of this pipe 33 is connected to a fluid port of a three-way ball valve 35. One end of a pipe 37 is connected to another fluid port of the three-way ball valve 35, and the other end of the pipe 37 protrudes from the outer frame 13 and is connected to an external vacuum pump 39. The remaining fluid ports of the three-way ball valve 35 are provided with a
1 is connected to one end of the plug 43, and the other end of the plug 43 protrudes into the outer frame 13 and is connected to the capillary 41.
The other end is open to the atmosphere.

With the above configuration, the two-way valve 27 is switched and the piping 25
When the three-way ball valve 35 is switched to connect the pipes 33 and 37, and the vacuum bomb 39 is operated for a certain period of time, the three vacuum pumps
The inside of the vacuum drying chamber 7 becomes a predetermined vacuum state, and the vacuum drying chamber 7
The object to be measured inside will be subjected to a vacuum drying process.

The vacuum bomb 39 is stopped, the three-way ball valve 35 is switched to connect the pipe 37 and the capillary 41, the pipes 33 and 37 are cut off, and the two-way valve 27 is switched to connect the pipes 27 and 29. As a result, inert gas flows from the gas supply device @ 31 to the vacuum drying chamber 7 via the piping 29, the two-way valve 27, and the piping 25.
supplied within. When a certain amount of inert gas is supplied into the vacuum drying chamber 7, the two-way valve 27 is switched to open the pipes 25 and 2.
9, the inert gas from the gas supply device 31 is no longer supplied to the vacuum drying chamber 7, and the inert gas inside the vacuum drying chamber 7 is maintained at a constant amount. Heat treatment will be performed.

To simply release the vacuum without filling the vacuum drying chamber 7 with inert gas, remove the gas supply device 31 and open it to the atmosphere, then switch the two-way valve 27 and connect the pipes 25 and 29.
By communicating with the -C vacuum drying chamber γ, the vacuum inside the -C vacuum drying chamber γ is released.

An example of a specific structure of the three-way ball valve 35 is the second one.
The three-way ball valve 35 has three fluid ports 35A, 35B, and 35 shown in FIG.
The fluid port 35A is connected to the pipe 37, the fluid port 35B is connected to the pipe 33, and the fluid port 35G is connected to a plug 43 on the right side of the capillary 41 shown in FIG. 2(B).

Inside the three-way ball valve 35 are the valves shown in FIG. 3 (p, >. (B).
As shown in (C), a ball 45 is provided, and in order to move this ball 45, for example, a switching handle 47 connected to the ball 45 is provided externally.

When this switching handle 47 is manually rotated by, for example, an operator, the ball 45 closes the fluid port 35C, as shown in FIG. The two are connected. Also, Figure 3 (B
), the ball 45 closes the fluid port 35B, the fluid ports 35A and 35G communicate with each other, and the pipe 37 and the capillary 41 communicate with each other.

In this way, Figure 3(A). When switching by turning the handle 47 as shown in (B), the three-way ball valve 35
As shown in FIG. 3(C), the ball 45 may be in a neutral state and the inlet 35A. Three sides of 35B and 35G are in communication state.

Therefore, the part of the vacuum drying chamber 7 that should be evacuated is communicated with the atmosphere and leaks. This leak occurs without the capillary 41 and in the case of a normal pipe diameter, if there is a leak of P1 shown in FIG. 4, it takes T+ time to return to the state without leak.

On the other hand, if there is a capillary 41 as in this embodiment, even if there is a slight leak of ΔP1 shown in FIG. 4, it takes only ΔP1 hour to return to the state without leakage. I can do it. Therefore, the capillary 4 is connected to the inlet 35G.
1, leakage can be reduced by providing the plug 43 having a diameter of 1.

FIG. 5 shows another embodiment in which the three-way ball valve 35 is automatically switched. In FIG. 5, parts that are the same as those in the embodiment described above are given the same reference numerals for explanation. In order to rotate the ball 45, a driving device 51 such as a servo motor is provided on the ball 45 via a connecting portion 49 such as a joint. This drive device 51 is attached to the mounting plate 5
It has been taken by 3 and 4. Roughly speaking, a control device 55 is connected to this drive device 51, and this control device 5
5 is connected to an electric FA device 57 of the vacuum bomb 39.

With the above structure, a signal to rotate the ball 45 of the three-way ball valve 35 is sent from the control III device 55 to the drive device 51, which drives the drive device 51, rotates the ball 45, and operates the vacuum drying chamber 7. and the three vacuum pumps, and can automatically start or stop the vacuum pump 39 by sending a signal from the control device 55 to the power supply device 57 of the vacuum pump 39. It is possible to eliminate erroneous operations by the operator and to prevent backflow of oil due to erroneous operations.

Note that the present invention is not limited to the embodiments described above, and can be implemented in other embodiments by making appropriate changes. For example, it is effective to use pipes 33 and 37 connected to the three-way pole valve 35 in this embodiment with pipes whose inner diameters change as little as possible.

[Effects of the Invention] As understood from the above description of the embodiments, according to the present invention, by operating the vacuum bomb and switching the three-way pole valve to create a vacuum, the vacuum drying chamber becomes evacuated. When the vacuum drying chamber reaches a predetermined degree of vacuum, this is done by switching the three-way pole valve to shut off, and then turning off the power to the vacuum bomb.

When the three-way ball valve is switched from "communicating" to "blocking," the vacuum drying chamber may be communicated with the atmosphere, causing a leak, but one fluid port of the three-way ball valve is equipped with a plug equipped with a capillary. As a result, the amount of leakage is minimized, and the vacuum level of the vacuum drying chamber can be returned to its original level in a short period of time with only a very small amount of leakage and no drastic reduction in the degree of vacuum.

In addition, since the three-way ball valve is switched by the drive device and the vacuum bomb is automatically stopped via the control device, it is possible to prevent backflow of oil due to erroneous operation, and to eliminate erroneous operation. I can do it.

[Brief explanation of drawings]

Fig. 1 shows the main parts of the present invention, and Fig. 2 (A) is a perspective view showing an example of a three-way ball valve, and Fig. 2 (B) is a schematic side cross-sectional view of a vacuum drying device. a cross-sectional view of a plug with capillaries provided in two fluid ports;
Figure 3 (A). (B) and (C) are explanatory diagrams of the operation when creating a vacuum, Figure 4 is a vacuum curve diagram depending on the pressure and time to achieve a vacuum state, and Figure 5 is a separate implementation that automatically controls the three-way ball valve and vacuum bomb. This is an example diagram.

Claims (2)

[Claims] (1) In order to evacuate the vacuum drying chamber in the vacuum drying device, a vacuum pump is connected to the vacuum drying chamber via piping, and a three-way ball valve is installed in the middle of the piping, and the two-way A leak device for a vacuum drying apparatus, characterized in that a fluid port communicates and shuts off the piping, and the remaining fluid port in one direction is provided with a plug equipped with a capillary communicating with the atmosphere. (2) In claim (1), a drive device is provided for automatically switching the three-way ball valve, and the vacuum pump is interlocked and connected to the drive device via a control device. Features a leak device in vacuum drying equipment.