JPH0249182B2 - TEIATSUCHUZOKINOKYUTOKEIHOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to storing hot water in which a material such as a low melting point metal is melted in a hot water tank, sealing the hot water tank, and discharging the water into the hot water tank. The present invention relates to a low-pressure casting machine that pressurizes gas to supply hot water in a hot water supply tank to a mold disposed above, and particularly relates to a hot water supply alarm device for the low pressure casting machine.

(Conventional technology) As a conventional technology, a mold is installed at the top of a hot water tank that seals and holds hot water containing molten material, and a stalk is installed whose upper end communicates with the sprue of the mold and whose lower end opens below the hot water surface of the hot water tank. and a gas supply device that pressurizes gas into the hot water tank.The gas supply device increases the pressure inside the hot water tank and supplies the hot water in the hot water tank to the mold.In this state, the gas supply device Some devices detect the amount of gas outflow, and when this detected value exceeds a predetermined value, an alarm device is activated to confirm an abnormality.

(Problems to be Solved by the Invention) In the conventional method described above, abnormalities were confirmed after hot water in the hot water supply tank was supplied to the mold.
If an abnormality occurs, the product molded by the mold may become defective, or the hot water supplied to the mold may leak outside, creating a danger.

SUMMARY OF THE INVENTION An object of the present invention is to obtain a new hot water supply alarm device for a low pressure casting machine that eliminates the above-mentioned drawbacks.

(Means for Solving the Problem) The present invention provides a first configuration for achieving the above object.
This will be explained based on the diagram.

A mold 6 is installed at the upper part of the hot water tank 1 that seals and holds hot water in which the material is melted, and the upper end is connected to the sprue 6b of the mold 6 and the lower end is connected to the hot water surface of the hot water tank 1 at the axial center of the hot water tank 1. A stalk 7 is provided that opens to the.

40 injects gas at a predetermined pressure into the hot water tank 1 to adjust the air pressure inside the hot water tank 1 so that the hot water level in the stalk 7 rises to the mold 6.
The pressure detector 41 detects the pressure inside the hot water tank 1 increased by the primary pressurizing means 40 .

43 is a first determination means, which compares the primary reference value (P ₂ ) corresponding to the primary pressure previously stored in the storage unit 42 and the detected value (Pm) of the pressure detector 41, and determines whether both are the same. When the pressure reaches substantially the same level, a stop command 44 is issued to the primary pressurizing means 40, and an operation command 45 is issued to the timer circuit 46.

The timer circuit 46 is used to set the timing of operation of the second determining means 48.

Upon receiving the determination command 47 from the timer circuit 46, the second determination means 48 determines that the lower reference value (P ₁ ) is at a slightly lower level than the primary reference value (P ₂ ) stored in advance in the storage unit 42 . , pressure detector 41
is compared with the detected value (Pm), and when the detected value (Pm) is at a lower level than the lower reference value (P ₁ ), an activation command 49 is issued to the alarm device 50.

(Function) Since the present invention has the above-mentioned configuration, when the hot water level in the stoke 7 reaches directly below the sprue 6b of the mold 6, it is left for a predetermined period of time, and then the degree of decrease in the atmospheric pressure in the hot water tank 1 is reduced. When this determination is made and the degree of descent exceeds a certain value, the alarm device 50 will be activated.

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIG. 2, reference numeral 1 denotes a cylindrical hot water tank with a bottom made of a heat insulating material such as a ceramic material. It will be connected to.

The upstream part of the hot water storage tank 4 located on the left side in FIG. 2 is connected to a melting furnace (not shown), and the hot water in the hot water storage tank 4 is maintained at a substantially constant level at all times by hot water supplied from the melting furnace. It is becoming more and more common.

Further, the hot water valve 3 is disposed at a downstream portion of the hot water storage tank 4, and is tapered fitted into an upstream end portion of a communication passage 2 that opens upward in a bottom wall 4a of the downstream portion.

That is, the upstream end portion is formed as a tapered hole 2a that widens upward, the lower end portion of the hot water valve 3 is formed as a tapered shaft 3a that narrows downward, and this tapered shaft 3a is connected to the tapered hole 2a. to fit.

When the hot water valve 3 is opened and the hot water A in the hot water tank 4 flows into the hot water tank 1 due to its own weight, the hot water level A in the hot water tank 4 is located at the upper part of the hot water tank 1. Set it so that it is balanced with the water level.

The upper surface of the hot water tank 1 described above is closed by a lid 5, and a mold 6 made of a metal mold is placed on the upper surface of the lid 5.

The mold 6 has a cavity 6a filled with hot water, and a sprue 6a in the center of the bottom of the mold 6.
b.

Further, a stalk 7 is supported under the weight at the center of the lid 5. The stalk 7 has its upper end communicated with the sprue 6b, and its lower end opened at the bottom of the hot water tank 1.

A pipe 8 is provided at the top of the hot water tank 1 to allow gas to flow into or out of the upper space of the hot water tank 1. An exhaust pipe 9 and an air supply pipe 11 located outside the pipe 8 are connected in parallel to the outer end of the pipe 8, and the exhaust pipe 9 is equipped with an exhaust valve 10 for opening and closing the exhaust pipe 9, and the air supply pipe 11 is equipped with an exhaust valve 10 for opening and closing the exhaust pipe 9. An air supply valve 12 is provided respectively.

The air supply pipe 11 is connected to a gas pressure source 14a such as an air pump via a pressure control device 13 outside the air supply valve 12.

In the pressure control device 13, for example, two pressure control valves are connected in parallel between the air supply valve 12 and the gas pressure source 14a, and one pressure control valve is connected so that the hot water level in the stoke 7 is equal to that of the mold 6. The primary pressure is set to reach directly below the sprue 6b, and the other pressure control valve is set to a hot water supply pressure value _P3 , such as 2000 mmAq, at which the hot water in the stoke 7 is filled into the cavity 6a of the mold 6 at a predetermined pressure. Become.

41 is a pressure detector that detects the atmospheric pressure in the upper space of the hot water tank 1; 16 is an air cylinder that drives the hot water valve 3 in the up and down (opening and closing) directions; Connect to.

Here, the aforementioned exhaust valve 10, air supply valve 12, pressure control device 13, and switching valve 17 (hot water valve 3) are driven and controlled by a control device 20 (microcomputer).

The control device 20 mainly includes a microprocessor (central processing unit) 20a, a memory, that is, a storage section 20b, and an interface (input/output signal processing circuit) 20c.

The atmospheric pressure in the hot water tank 1 is detected by a pressure detector 41, and this detected value is input as a digital signal to the interface 20c.

In addition, the interface 20c includes an exhaust valve 1.
0 and opening/closing of the air supply valve 12, pressure control device 13
On/off signals are input from each switch (not shown) that detects the operating position of the switching valve 17.

The primary reference value P ₂ corresponding to the primary pressure in the hot water tank 1 is stored in the memory, that is, the storage unit 20b.
For example, 1600 mmAq and a lower reference value P ₁ slightly lower than this, for example 1500 mmAq, are stored, and the corresponding control value is read out in accordance with the signal from the pressure detector 41.

FIG. 3 shows a flowchart of the control device 20.

First, when the hot water valve 3 is opened and the hot water level A in the hot water supply tank 1 is at the same level as the hot water level in the hot water storage tank 4,
When the start 21 is started, the switching valve 1 is switched on in step 22.
7 is operated in one direction, compressed air from the gas pressure source 14b flows into the upper chamber 16a of the air cylinder 16, and the air cylinder 16 is operated to extend.Therefore, the hot water valve 3 is operated to close, and the hot water tank 1 is opened. It will be cut off from the hot water tank 4.

Next, in step 23, the exhaust valve 10 is closed, and the exhaust pipe 9 is closed.

Next, in step 24, the air supply valve 12 is opened, and then in step 25, the pressure control device 13 is first operated (one pressure control valve is opened), and the compressed air from the gas pressure source 14a ( Inert gas) is fed under pressure into the hot water tank 1 via the supply pipe 11 and pipe 8 (primary pressurizing means 40).

The above-mentioned pressure feeding is continued until the detection value Pm of the pressure detector 41 reaches the primary reference value _P2 as shown in FIG. , the hot water level U is hot water tank 1
It is located higher than the standard hot water level A in the mold 6 and directly below the sprue 6b of the mold 6. Then, when the detected value Pm of the pressure detector 41 reaches the primary reference value _P2 ,
At step 27, the air supply valve 12 is closed, and the interior of the hot water tank 1 is shut off from the outside (first determining means 43).

Next, in step 28, the above-mentioned cutoff elapsed time T ₂
It is checked whether the time has reached a predetermined time Tm, for example, 5 seconds (timer circuit 46).

Next, in step 29, the detected value of the pressure detector 41 is
Check whether Pm is greater than or equal to the lower standard value _P1 ,
If Pm<P ₁ , the atmospheric pressure Pm<P ₁ is determined in step 32.
It is checked whether or not this is the second or more time, and if this is the second or more time, the process proceeds to step 33 and an alarm device 50 such as a buzzer is sounded (second determining means 48).

Note that the present invention provides an alarm system that, when the above-mentioned atmospheric pressure Pm becomes lower than the atmospheric pressure _P1 in step 29,
It is also possible to proceed directly to step 33 and cause the alarm device 50 to sound.

On the other hand, if the detected value Pm is greater than or equal to the lower reference value _P1 , the process proceeds to step 30 to open the air supply valve 12, and then proceeds to step 31 to open the pressure control device 1.
3 is activated as a secondary operation (the other pressure control valve is opened), the pressure inside the hot water tank 1 is increased to the hot water supply pressure value P ₃ as shown in FIG. The liquid is supplied to the cavity 6a of the mold 6 through the medium.

Further, in step 32, if the above-mentioned detected value Pm< _P1 is the second time or less, the process proceeds to step 34, in which the air cylinder 16 is slightly shortened via the switching valve 17, and the hot water valve 3 is closed. Move slightly open. This causes the hot water in the hot water tank 1 to flow back toward the hot water storage tank 4 using the atmospheric pressure generated within the hot water tank 1.

Next, in step 35, the exhaust valve 10 is opened to lower the pressure inside the hot water tank 1 to atmospheric pressure.

Then, in step 36, the air cylinder 16 is shortened via the switching valve 17, the hot water valve 3 is opened, and the hot water in the hot water tank 4 is recirculated into the hot water tank 4 by its own weight.
After the liquid is allowed to flow, proceed to step 22.

This allows the hot water to flow in the valve part (taper fitting part) of the hot water valve 3 in the forward and reverse directions, promotes the removal of foreign matter adhering to the valve part, and restores the sealing performance of the valve part. Do it like this. The above-mentioned predetermined time Tm, lower standard value P ₁ and primary standard value P ₂ are based on the seal structure of the hot water tank 1, the specific gravity of the hot water supplied into the hot water tank 1, the surface level of the hot water in the hot water tank 1, and the shape of the hot water. 6 sprue 6b
Determine as appropriate depending on the height, etc.

(Effects of the Invention) As is clear from the above explanation, the present invention is capable of
The airtightness of the hot water tank, etc. is checked, and if the airtightness is less than the specified level, an alarm device is activated, so that the product does not become defective and the hot water supply of the low-pressure casting machine is safe. This has the effect of providing an alarm device.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the present invention, Fig. 2 is a block diagram showing an embodiment of the invention, Fig. 3 is a flowchart of the control device, and Fig. 4 shows changes in the atmospheric pressure in the hot water tank. It is a pressure characteristic diagram. 1: Hot water tank, 2: Communication furnace, 2a: Tapered hole,
3: Hot water valve, 3a: Tapered shaft, 4: Hot water tank, A:
Hot water, 5: Lid, 6: Mold, 6a: Cavity, 6b:
Sprue, 7: Stoke, 8: Pipe, 9: Exhaust pipe,
10: Exhaust valve, 11: Air supply pipe, 12: Air supply valve, 1
3: Pressure control device, 14a, 14b: Gas pressure source, 16: Air cylinder, 17: Switching valve. 20:
Control device, 40: Primary pressurizing means, 41: Pressure detector, 42: Storage section, 43: First determination means, 46:
Timer circuit, 48: second determination means, 50: alarm device.

Claims (1)

[Claims] 1. A mold is installed on top of the hot water tank that seals and holds the hot water in which the material is melted, and a stalk is installed whose upper end communicates with the sprue of the mold and whose lower end opens below the hot water surface of the hot water tank, and gas is pressurized into the hot water tank. In a low-pressure casting machine that supplies hot water in a hot water tank into a mold, gas at a predetermined pressure is injected into the hot water tank to increase the air pressure in the hot water tank until the hot water level in the stoke reaches just below the sprue of the mold. A primary pressurizing means that increases the pressure to the primary pressure, a pressure detector that detects the atmospheric pressure in the hot water tank, an alarm device, a primary reference value that corresponds to the primary pressure, and a lower standard value that is a predetermined value lower than the primary standard value. A memory section for storing information and a timer circuit are provided, and when the detected value of the pressure detector reaches a value corresponding to the primary reference value, a stop command is issued to the primary pressurizing means, and a timer circuit is provided that issues an operation command to the timer circuit. 1 judgment means receives a judgment command from the timer circuit, compares the detected value of the pressure detector with the lower reference value, and issues an activation command to the alarm device when the detected value of the pressure detector is at a lower level than the lower reference value. 1. A hot water supply alarm device for a low pressure casting machine, characterized in that a second determination means for emitting an alarm is provided.