JPH0152630B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is such that when the gas in a high-pressure gas cylinder that is supplying gas to a consumer is exhausted, gas is automatically supplied from another new high-pressure gas cylinder to the consumer. Concerning an automatic switching valve device for gas supply that enables constant supply of gas without interruption,
In particular, the present invention relates to the switching valve device with an alarm, which prompts replacement of the high-pressure gas cylinder by giving a timely warning that the gas cylinder is exhausted.

Conventionally, for example, in hospitals, etc., in order to supply oxygen gas to each patient room, operating room, etc., first and second high-pressure gas cylinders A and B are prepared as shown in Fig. 1, and a check valve A for the cylinders A and B is used. ', B' and the first and second inlets 2, 2' of the automatic gas switching valve 1 are connected via the first and second pressure reducing valves 3, 3', respectively, and the pressure reducing valve 3 , 3', the first and second
An automatic switching valve device for gas supply is used, which is equipped with high-pressure side gas pressure switches 4, 4' and first and second low-pressure side gas pressure switches 5, 5'.

In the above device, the first and second high-pressure side gas pressure switches 4 and 4' are configured to switch the first and second high-pressure gas cylinders A and B from high pressures of, for example, 150 kg/cm ² to 50 kg/cm ² . This is installed to detect that the pressure has dropped to the level of
From high pressure gas cylinder A through automatic gas switching valve 1,
While gas is being supplied to the consumer from the gas supply port 6, the second high-pressure gas cylinder B, which is about to be used, is inadvertently emptied due to gas leakage from the piping system. This is to prevent such things from happening.

Next, the first and second low-pressure side gas pressure switches 5 and 5' are provided because the high pressure of 150 kg/cm ² as in the above example is adjusted to 9 kg by means of the first and second pressure reducing valves 3 and 3'. The pressure is reduced to a low pressure of about 9 kg/cm ² and gas is supplied to the automatic gas switching valve ¹ at the adjusted predetermined low pressure. The low pressure will drop, so for example 7
This is so that when the gas pressure drops to Kg/cm ² , each pressure switch 5, 5' detects this, warns in advance that the first or second high-pressure gas cylinder is exhausted, and prompts the cylinder to be replaced. .

By the way, as the above-mentioned conventional automatic gas switching valve 1, the applicant has already proposed the one shown in FIG.

That is, in the same figure, a movable piston 10 fitted with O-rings 9, 9' is located on the left side in a cylinder 8 in which the first and second inlet ports 2, 2' of the valve body 7 are opened, and the movable piston 10 is located on the left side. Gas is being supplied from the gas cylinder A side, but at this time, the gas pressure that the right end surface of the movable piston 10 receives is greater than the gas pressure that the left end surface receives by the difference in pressure receiving area, so the left end surface is The second introduction port 2' is closed by pressing against 11' of the gaskets 11, 11', and at this time, the O-ring 9 of the movable piston 10 comes into contact with the cylinder small diameter portion 8' of the valve body 7, and thereby The left and right sides of the cylinder 8 are airtightly separated, thus preventing gas leakage from the right side to the left side of the cylinder 8.

Therefore, the gas sent to the right side of the cylinder 8 is transferred to the right side 1 of the gas switching ports 12, 12'.
2 is pushed down against the elasticity of the coil spring 14, and thus gas is supplied to the consumer from the gas supply port 6 communicating with the gas switching ports 12, 12'. The valve 13' provided at the other gas switching port 12' receives the gas flow pressure at the gas supply port 6 and the elastic force of the coil spring 14', so that the gas switching port 12' is closed.

In addition, the valve body 7 has an atmospheric pressure inlet 15 that opens at the center of the cylinder small diameter section 8', and the left side of the cylinder 8 in FIG. 2 is at atmospheric pressure. The operation of closing the gas switching port 12' by the valve element 13' described above is performed quickly and reliably.

However, as mentioned above, as the gas in the first high pressure gas cylinder A is consumed and the gas pressure on the low pressure side of the first pressure reducing valve 3 decreases, the movable piston When the gas pressure difference between the gas pressure and the gas pressure applied to the movable piston 10 increases, for example, when the same pressure difference reaches 3.5 kg/cm ² , the movable piston 10
moves to the right by the gas pressure from the second high-pressure gas cylinder B, and its right end surface is the gasket 11 of the first inlet 2.
This leads to the blockage.

As a result, gas from the second high-pressure gas cylinder B passes through the second inlet 2' and pushes down the valve 13'.
Gas can be supplied from the gas switching port 12' through the gas supply port 6. At this time, the high-pressure gas cylinders A and B are replaced with new ones one after another, thereby making it easier for customers to use the gas. This will ensure continuous gas supply.

However, using the automatic gas switching valve 1 with the above configuration,
As mentioned above, the first and second high pressure gas cylinders A,
When attempting to issue a warning that B was exhausted, a situation sometimes occurred in which the high-pressure gas cylinder was already empty, even though the warning was not issued.

When we investigated the cause of this situation, we discovered the following phenomenon.

That is, when using the above automatic gas switching valve 1,
As shown in Figure 3, when the first high-pressure gas cylinder A starts to be supplied to the consumer at a gas pressure (P) of 5 kg/cm ² as shown by the solid line _S1 , the low-pressure side gas pressure on the cylinder A side is horizontal. As shown by the solid line _L1 , it is 9Kg/ ^cm2 , and the low pressure side gas pressure of the unused second high pressure gas cylinder B is also 9Kg/cm2, as shown by the horizontal dotted line _L2.
cm ² .

However, as the gas is used by the gas consumer, at time _T1 in the elapsed time T, the low-pressure side gas pressure of the first high-pressure gas cylinder A decreases as indicated by the sloping solid line _L3 , and the alarm generation line L reaches 7Kg/ ^cm2
When this occurs, the first low pressure side pressure switch 5 detects this at time _T2 in the figure, and an alarm lamp (not shown) is activated.
Turn on the buzzer, etc. and make it sound.

If the pressure drop continues further and a gas pressure difference of 3.5 kg/cm ² occurs between the low-pressure side gas pressures of the first and second high-pressure gas cylinders A and B, the automatic gas switching valve 1
is activated, and at time _T3 , the first high pressure gas cylinder A
The supply source is switched from to the second high pressure gas cylinder B as shown by the horizontal dotted line _S2 , and the low pressure side gas pressure of B is 9.
Gas is supplied as shown by the horizontal dotted line _L4 at a set pressure of Kg/ ^cm2 .

On the other hand, the first high-pressure gas cylinder A will be replaced with a new cylinder after the time indicated by the horizontal solid line L ₅ has elapsed, but at the same time the new cylinder's check valve
When A' is opened by the rapid opening operation that is often operated, despite the presence of the first pressure reducing valve 3,
The low-pressure side gas pressure suddenly rose to 11-12 Kg/cm ² instead of the set value of 9 Kg/cm ² at time T ₄ of the opening, and this increased pressure state remained unchanged. This results in a continuous reality as shown by the horizontal solid line _L6 .

This phenomenon is due to the structure of the pressure reducing valve as shown in Fig. 4, and when gas flows from the high pressure side inlet 3'' of the pressure reducing valve 5 due to the rapid opening as described above, the valve enters the open state. The gas pushes up the diaphragm 17 from a certain regulating valve 16 and flows into the decompression chamber 18, increasing the static pressure in the chamber 18 to about 11 to 12 kg/cm ² as described above. If valve A' is gradually opened, such an abnormal pressure increase will not occur, and the set value of 9 kg/cm ² determined by the elastic force stored in the spring 20 by adjusting the adjustment screw 19 will be maintained. However, it is difficult to always expect workers to perform such operations.

For the above reasons, under the condition where the low-pressure side gas pressure on the first high-pressure gas cylinder A side is high as in L ₆ , on the second high-pressure gas cylinder B side,
Due to its use, the low-pressure side gas pressure decreases as shown by the inclined dotted line _L7 at time _T5 , so the low-pressure side gas pressure difference between both cylinders A and B becomes large, and eventually an alarm of 7 kg/cm ² is generated. Before the pressure drops to the generation line L, the supply source from the second high pressure gas cylinder B to the first high pressure gas cylinder A is transferred to the horizontal dotted line at time T ₆ .
As a result, the oxygen gas is switched as shown in S ₃ , and as a result, the person does not know that the B has been exhausted, so the time to replace it with a new cylinder is lost, and the oxygen gas supply at hospitals etc. is interrupted. If it is interrupted, serious problems may occur.

Now, if the cylinder B is switched to A as described above, gas is supplied from the cylinder A, so the high static pressure shown by L ₆ is 9 as a dynamic pressure.
Kg/cm ² , and on the other hand, even if the cylinder B is replaced with a new cylinder at time T ₇ as shown by the horizontal dotted line L ₈ and the check valve B' is slowly opened,
In the case of the pressure reducing valve illustrated in Fig. 4, the regulating valve 1
6 and its valve seat 16'.
In some cases, so-called seal leakage may occur, and in such a situation, the low-pressure side gas pressure on the cylinder B side gradually increases as shown by the sloped dotted line _L9 , and as a result, the _above from time T8 As is clear from the sloping solid line _L10 related to cylinder A, the same cylinder A is located before the alarm generation line L as before.
The switching from to B occurs at time _T9 as shown by the horizontal dotted line _S4 , resulting in a malfunction in which the alarm is not generated.

The present invention has been studied based on the above-mentioned investigation into the causes of malfunctions, and is based on the above-mentioned automatic gas switching valve. The aim is to overcome the above-mentioned drawbacks of conventional devices by providing a spout.

The present invention will be described in detail with reference to FIGS. 5 and 6. The basic configuration is the same as that illustrated in FIGS. 1 and 2, and the automatic gas switching valve 21 in FIG.
Identical members are designated by the same reference numerals.

The difference between the figures is regarding the movable piston 10, with respect to the left and right ends of the same piston 10.
In addition to simply forming pressure-receiving large-diameter recesses 22 and 22', both the recesses 22 and 22' communicate with each other through a narrow pressure regulating port 23, and therefore the cylinder 8 is Both the left and right sides are in communication.

When the automatic gas switching valve 21 is formed using the movable piston 10 having the above configuration, in FIG. 6, L ₁ , L ₃ , and L ₅ are passed in the same way as in FIG. When the check valve A' of the high-pressure gas cylinder A is rapidly opened, the first pressure reducing valve 3 is opened at _T4 .
The gas pressure on the low pressure side of 2 is increased, and the gas is transferred from the pressure receiving large diameter recess 22' to the pressure regulating narrow opening 2.
3-Since the pressure gradually flows to the right side of the cylinder 8 through the large-diameter pressure-receiving recess 22, it differs from L ₆ in FIG. 3, as shown by the solid line L ₆ ' with a negative slope. , the above-mentioned pressure increase state is not sustained and is reduced to a normal state at time T ₄ ′ 9
Kg/cm ² and then L ₄ followed by slope dotted line
Since L ₇ has arrived, an alarm can be issued at time T ₅ ' as well as at time T ₂ .

Furthermore, even if the phenomenon described with respect to L ₉ in FIG. 3 occurs at time T ₇ , _the low-pressure side gas pressure on the high-pressure gas cylinder B side is Without continuing to rise, the gas flow through the narrow pressure regulating port 23 causes small fluctuations in the gas pressure in a pulsating state, so that the gas pressure reaches the point T at the intersection of the sloped solid line _L10 and the alarm generation line L. ₈ ', an alarm can be issued.

In the present invention, as embodied by the above-described embodiment, the first and second high-pressure gas cylinders A and B are connected to the first and second automatic gas switching valves via the first and second pressure reducing valves 3 and 3', respectively. connected to the second inlets 2, 2';
When the gas pressure difference on each low pressure side of the second pressure reducing valves 3, 3' becomes larger than a predetermined value, the movable piston 10 of the automatic switching valve operates to switch due to the gas pressure difference, and until then the automatic switching occurs. The high-pressure gas cylinder that was supplying gas from the gas supply port of the valve is switched to supply from another high-pressure gas cylinder, and the low-pressure sides of the first and second pressure reducing valves 3 and 3' are provided with:
In an automatic switching valve device for gas supply, which is provided with first and second low-pressure side gas pressure switches 5, 5' for warning when the gas pressure has decreased to a set value and prompting replacement of the cylinder. Since the movable piston 10 of the automatic gas switching valve 21 is provided with a narrow pressure regulating port 23 that communicates the first and second inlet ports 2 and 2', how should the check valve of the high pressure gas cylinder be configured? Even if the pressure reducing valve is operated normally, or if a situation such as seat leakage occurs in the pressure reducing valve, the alarm by the low pressure side gas pressure switches 5 and 5' can be activated reliably, and there will be no alarm. It is possible to eliminate serious troubles such as the interruption of gas supply to consumers due to the timing of replacing high-pressure gas cylinders being missed.

[Brief explanation of drawings]

Figure 1 is a piping system diagram of the automatic gas switching valve device for existing gas supply, Figure 2 is a longitudinal sectional front view showing the automatic gas switching valve of the same device, and Figure 3 is the low pressure side gas pressure of the pressure reducing valve in the same device. Fig. 4 is a longitudinal sectional front view of the pressure reducing valve, Fig. 5 is a longitudinal sectional front view showing the automatic gas switching valve of the automatic switching valve device for gas supply with alarm according to the present invention, and Fig. 6 is the same device. It is a low-pressure side gas pressure fluctuation progress chart of the pressure reducing valve in . 2, 2'...first, second inlet port, 3,3'...first,
2nd pressure reducing valve, 5, 5'...first, second low pressure side gas pressure switch, 10...movable piston, 21...automatic gas switching valve, 23...thin opening for pressure regulation, A, B...first, first 2 high pressure gas cylinders.

Claims (1)

[Claims] 1 The first and second high pressure gas cylinders are connected to the first and second inlets of the automatic gas switching valve via the first and second pressure reducing valves, respectively, and the gas on each low pressure side of the first and second pressure reducing valves is connected to the first and second inlet ports of the automatic gas switching valve. When the pressure difference becomes larger than a predetermined pressure value, the movable piston of the automatic gas switching valve switches due to the gas pressure difference, reducing the high pressure that was previously being supplied from the gas supply port of the automatic gas switching valve. The gas cylinder is switched to supply from another high-pressure gas cylinder, and the low-pressure side of each of the first and second pressure reducing valves detects that the gas pressure has decreased to a set value and prompts replacement of the cylinder. In an automatic gas supply switching valve device that is provided with a low-pressure side pressure switch for alarm, the movable piston of the automatic gas switching valve is provided with a narrow passage for pressure regulation that communicates the first and second inlet ports. An automatic switching valve device for gas supply with an alarm, characterized by: