JPS6212944Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention maintains the valve body open during normal flow.
The present invention relates to an automatic shutoff valve in which a valve body is automatically closed in response to leakage on the downstream side of a valve seat, and furthermore, the valve body is configured to be closed by external operation in the event of an emergency such as an earthquake.

[Prior Art] Conventionally, as shown in FIG. 5, a case is divided into a first case divided portion 23a, a second case divided portion 23b,
The third case divided portion 23c is formed into three parts, and the first
Case divided portion 23a and second case divided portion 23
b forms flow passages 26a and 26b having the valve seat 24 and the valve body 25 on the upstream side thereof, and separate from the flow passages 26a and 26b by the second case division part 23b and the third case division part 23c. The space created,
The diaphragm 27 divides the pressure chamber into a first pressure chamber 28a and a second pressure chamber 28b, and a rod 29 that connects the valve body 25 and the diaphragm 27 is passed through the second split case portion 23b to connect the sealing diaphragm 30. Therefore, the flow path 26a and the first pressure chamber 28a
A pressure guiding path 32 is provided which connects the flow path 26b on the downstream side of the valve seat 24 and the first pressure chamber 28a.
are formed in the first case divided portion 23a and the second case divided portion 23b, and a first atmosphere opening flow path 33a that connects the pressure guiding path 32 to the atmospheric space is formed in the second case divided portion 23b. 32 and the first atmosphere opening channel 33a are provided in the second case divided portion 23b, and the second pressure chamber 28
A second atmosphere opening flow path 33 that connects b to atmospheric space.
b is formed in the third case divided portion 23c (see, for example, Japanese Utility Model Application Publication No. 150127/1983).

That is, as shown in FIG. 5, during normal flow, the pressure on the downstream side of the valve seat 24 (gauge pressure P) is applied to the first pressure chamber 28a by the pressure guiding path 32, and the diaphragm is 27 (effective area a ₁ )
Due to the valve opening force P×a ₁ acting on the spring 3
against the resultant force F 1 +F ₂ of the valve closing force F ₁ due to ₁ and the valve closing force F ₂ due to the gravity of the valve body 25, that is, P×a ₁ >
The valve body 25 was configured to maintain the valve open by F ₁ +F ₂ .

Additionally, if a pressure drop (gauge pressure ΔP) occurs due to leakage downstream of the valve seat 24, the spring 31
The valve closing force due to the valve closing force F ₁ and the valve closing force due to the gravity of the valve body 25
Due to the resultant force F ₁ +F ₂ of F ₂ , the valve opening force (P - Δ
P)×a ₁ , that is, F ₁ +F ₂ > (P−ΔP)×
a ₁ to close the valve body 25.

As shown in FIG. 6, when the valve body 25 is closed, the valve closing force P×a 3, which is the product of the opening area a ₃ of the valve seat 24 and the upstream pressure (gauge pressure P), is applied to the valve body ₂₅ . 2
In addition to the valve closing force F ₁ +F ₂ +P×a ₃ , the valve is stably kept closed regardless of pressure fluctuations on the upstream side of the valve seat 24.

Furthermore, as shown in FIG. 7, when the second pressure chamber 28b is opened to the atmosphere by the operating valve 34 in the event of an emergency, the valve closing force F ₁ by the spring 31 and the valve body 25 in the open state shown in FIG. Due to the resultant force F ₁ +F ₂ of the valve closing force F ₂ due to gravity, the valve opening force (P x _{a 4} ), that is, F ₁ +F ₂ >
P×a ₄ and the valve body 25 was configured to close.

Then, as shown in FIG. 7, when the valve body 25 is closed, the valve closing force (P×a ₃ ) is added to the resultant force F ₁ +F ₂ and stabilized, similar to the case when the leakage occurred. The valve was configured to remain closed.

[Problem that the invention attempts to solve]

However, since the case is divided into three parts, the structure is complicated, and since the downstream flow path 26b of the valve seat 24 and the first pressure chamber 28a are formed separately, the case becomes large and the valve seat 24 is separated. Since the pressure guiding path 32 connecting the downstream flow path 26b and the first pressure chamber 28a is formed in the two case division parts 23a and 23b, the structure is complicated, and a diaphragm for sealing the penetration part of the rod 29 is required. 30, the structure is complicated.

An object of the present invention is to simplify and downsize the structure while maintaining the functions necessary for the automatic shutoff valve described above.

[Means for solving problems]

The characteristic structure of the present invention is that the case is divided into two parts, a first case division part and a second case division part, and a diaphragm is provided that divides the inside of the case into two parts, and in cooperation with the diaphragm, the flow downstream of the valve seat is Michikane 1st
A valve seat is provided in the first case divided portion forming a pressure chamber with an opening facing the diaphragm, a valve body is disposed downstream of the valve seat and attached to the diaphragm, and a valve body is attached to the diaphragm. A biasing means is provided which acts to bring the valve closer to the valve seat, and a space formed by the second case division part and the diaphragm is provided with a biasing means that acts to bring the valve closer to the valve seat, and a space formed by the second case division part and the diaphragm is
An auxiliary diaphragm is provided that partitions the pressure chamber and the third pressure chamber, and the peripheral part of the auxiliary diaphragm is connected to the diaphragm and the center part is connected to the second case division part, and the second pressure chamber of the diaphragm is connected to the diaphragm. A pressure guiding hole communicating with the second pressure chamber is formed between the valve body and the diaphragm with its inlet facing the opening of the valve seat. a pressurizing flow path connecting the second pressure chamber and the third pressure chamber is formed in the auxiliary diaphragm and the second case division part, and an atmospheric release flow path connecting the third pressure chamber to the atmospheric space; a passage is formed in the second case divided part, and an operating valve that selectively opens the atmosphere opening passage and the pressurizing passage is provided in the second case divided part, and the operation valve is provided in the second case divided part, and is located upstream of the valve seat during normal flow. gauge pressure P on the side and downstream side, reduced gauge pressure ΔP due to leakage on the downstream side of the valve seat, valve closing force F ₁ due to the biasing means, valve closing force F ₂ due to the gravity of the valve body, The effective area a ₁ of the diaphragm and the area a ₂ of the diaphragm portion facing the second pressure chamber are determined by the following formula: P×(a ₁ −a ₂ )>F ₁ +F ₂ >(P−ΔP)×(a ₁ −
_a2 ), and its effects are as follows.

[Effect]

During normal flow, as shown in FIG. 1, the operation valve 17 opens the atmosphere opening channel 21 and closes the pressurizing channel 22, and the valve is opened by pressure from the first pressure chamber _S1 to the diaphragm 5. Since the second pressure chamber S ₂ and the first pressure chamber S ₁ have almost the same pressure, the force is P×(a ₁ −
a ₂ ) and the gauge pressure in the third pressure chamber S ₃ is zero, so _the valve closing force is the _resultant force (F ₁ +F ₂ ), and since P×(a ₁ −a ₂ )>F ₁ +F ₂ , the valve body 8 is maintained open.

Then, when a leak exceeding the set amount occurs on the downstream side of the valve seat 7 and the gauge pressure becomes below (P-ΔP), the valve opening force decreases to (P-ΔP)×(a ₁ - a ₂ ), The valve closing force remains unchanged at (F ₁ + F ₂ ), and (P - ΔP) × (a ₁ -
Since a ₂ )<F ₁ +F ₂ , the valve body 8 is closed.

Furthermore, when the valve body 8 is fully closed, the second pressure chamber _S2 is connected to the upstream side of the valve seat 7 through the pressure guiding hole ₁₂ , as shown in FIG. The gauge pressure is almost equal to the gauge pressure P on the upstream side of the valve seat,
Since the gauge pressure in the first pressure chamber _S1 becomes almost zero due to leakage, the valve opening force is the product of the opening area _a3 of the valve seat 7 and the gauge pressure P on the upstream side of the valve seat 7 (P x a ₃ ) becomes;
The valve closing force is the valve closing force (P×a ₂ ) due to the pressure from the second pressure chamber S ₂ to the diaphragm 5, the valve closing force F ₁ due to the urging means 14, and the valve closing force F ₂ due to the gravity of the valve body 8. The resultant force is (P×a ₂ +F ₁ +F ₂ ), and the area of the diaphragm portion 5a facing the second pressure chamber S ₂ is larger than the opening area a ₃
Since a ₂ is large, P×a ₃ <P×a ₂ +F ₁ +F ₂ , and the valve can be stably kept closed regardless of pressure fluctuations on the upstream side of the valve seat 7.

In the event of an emergency, the operation valve 17 is automatically or artificially operated from the state shown in FIG. S ₁ , second pressure chamber S ₂ and third pressure chamber
The pressure chambers S ₃ are connected to each other and have approximately the same gauge pressure P. Therefore, the valve opening force and the valve closing force caused by the pressure on the diaphragm ₅ become almost zero, and the _resultant force (F ₁ +F ₂ ), the valve body 8 is closed.

When _{the valve} body 8 is fully closed, as shown in FIG. The gauge pressures of the second and third pressure chambers S ₂ and S ₃ are approximately equal to the gauge pressure P on the upstream side of the valve seat;
Since the gauge pressure in the first pressure chamber _S1 becomes almost zero due to fluid outflow, the valve opening force is calculated by the product of the opening area _a3 of the valve seat 7 and the upstream gauge pressure P of the valve seat 7 (P x a ₃ ), and the valve closing force is the valve closing force (P×a ₁ ) due to the pressure from the second and third pressure chambers S ₂ and S ₃ to the diaphragm 5,
The resultant force of the valve closing force F ₁ by the urging means 14 and the valve closing force F ₂ due to the gravity of the valve body 8 (P×a ₁ +F ₁ +F ₂ ) is obtained.
Since the area a ₁ of the diaphragm 5 is larger than the opening area a ₃ , P×a ₃ <P×a ₁ +F ₁ +F ₂ and the valve can be stably closed regardless of pressure fluctuations on the upstream side of the valve seat 7. Can be maintained.

In short, the valve can be kept open during normal flow, automatically closed and shut off when a leak occurs, and closed and shut off by external operation when an emergency situation occurs.

Moreover, since cases A ₁ and A ₂ are split into two,
The case structure can be simplified compared to the three-divided conventional technology described above, and the downstream flow path of the valve seat 7 is also used as the first pressure chamber _S1 , so the case can be made smaller than the previously described conventional technology with separate formations. A short and simple pressure guiding hole 12 that penetrates the valve body 8 and the diaphragm 5, and a short and simple air opening flow path 21 and pressurization flow path 22 formed in the second case divided portion _A2 are provided. Since it is only necessary to form the valve body, the structure can be simplified compared to the conventional technology described above which has a complicated pressure guiding path extending over two long case division parts, and there is no need for a rod to connect the valve body 8 and the diaphragm 5. Therefore, the structure can be simplified compared to the prior art which includes the aforementioned rod and a sealing diaphragm for the rod penetrating portion, and the automatic shutoff valve as a whole can be sufficiently simplified and miniaturized.

Incidentally, it is conceivable to simplify the automatic shutoff valve by using a known valve structure as shown in FIG. 8, but such a structure cannot achieve miniaturization of the automatic shutoff valve. In other words, in the cut-off state,
The valve closing force is the resultant force (F ₁ + F ₂ ) of the valve closing force F ₁ by the spring 35 and the valve closing force F ₂ due to the gravity of the valve body 36, and the valve opening force is the gauge pressure P on the upstream side of the valve seat 37. It is the product (P x a ₃ ) of the opening area a ₃ of the valve seat 37, and in order to stably shut off even if the gauge pressure P on the upstream side of the valve seat increases several times, it is necessary to close the valve. Force (F ₁ +
F ₂ ) must be made extremely large. On the other hand, in order to resist such an extremely large valve closing force (F ₁ +F ₂ ) and keep the valve open during normal flow, the valve opening force, that is, the gauge pressure P on the downstream side of the valve seat and the diaphragm 38
It is necessary to make the product (P×a ₁ ) of the effective area a ₁ extremely large, which makes the diaphragm 38 large.

However, according to the present invention, the pressure on the upstream side of the valve seat is applied to the second pressure chamber S ₂ when shutting down due to a leak, and to the second and third pressure chambers S ₂ and S ₃ when shutting down due to an emergency situation. The valve closing force is changed in direct proportion to the pressure upstream of the valve seat, and stable shutoff is achieved regardless of the pressure upstream of the valve seat.Furthermore, during normal flow, the second pressure chamber S Since the valve-closing force caused by ₂ can be offset by a part of the valve-opening force caused by the first pressure chamber _S1 , the diaphragm 5 can be made smaller despite its strong shutoff function.

[Effect of idea]

As a result, while providing the automatic shutoff valve with excellent leakage and emergency shutoff functions, the structure can be sufficiently simplified and downsized compared to conventional valves, reducing manufacturing, cost, and installation costs. In either case, it has become possible to provide an even more superior automatic shutoff valve.

[Example] Next, an example will be shown with reference to FIGS. 1 to 3.

Cases A ₁ and A ₂ are connected to a first case divided portion A ₁ that communicates with a fluid inlet 1 and an outlet 2, and a second case divided portion A ₂ that is joined to the first case divided portion A _{1 .}
The periphery of the main diaphragm 5 is pressurized between the joining flanges 3 and 4 between both case divided parts A ₁ and A ₂ , and the inside of the cases A ₁ and A ₂ is divided into two by the diaphragm 5. The first case divided portion A ₁ and the diaphragm 5 cooperate to form a flow path downstream of the valve seat and a first pressure chamber S ₁ .

The first case divided part is in communication with the inlet 1.
A valve seat 7 is attached to the upper end of the cylinder 6 formed in A ₁ with its opening facing the diaphragm 5, and a valve body 8 disposed downstream of the valve seat 7 is attached to the diaphragm 5.
It is installed so that it can move up and down integrally on the bottom surface of the cylinder 6.
Reset valve 1 that opens and closes a bypass flow path formed in
5 is provided so that it can be manually opened and closed in a state where the valve is biased to close by a spring 16.

A ring 10 is integrally formed on a presser plate 9 attached to the upper surface of the diaphragm 5, and the peripheral part of the auxiliary diaphragm 11 is connected to the diaphragm 5 by the ring 10, and the central part is connected to the inward protrusion 13 of the second case division part _A2 .
The space formed by the second case divided portion _A2 and the diaphragm 5 is connected to the diaphragm 5.
It is divided into a second pressure chamber S ₂ and _a third pressure chamber S ₃ facing toward _the
The pressure in the third pressure chamber _S3 is applied to the diaphragm 5 as a valve closing force.

The portion 5a of the diaphragm 5 that receives the valve-closing force from the second pressure chamber _S2 is formed to have a larger area than the opening of the valve seat 7, and the weight 14 that applies the valve-closing force _F1 to the diaphragm 5 is formed by a holding plate. 9, and is configured so that the resultant force (F 1 +F 2 ) of the valve closing force F ₁ due to the weight 14 and the valve closing force F ₂ due to the gravity of the valve body 8 (F ₁ +F ₂ ) is always applied to the valve body 8.

A pressure guiding hole 12 is formed that passes through the valve body 8, diaphragm 5, and presser plate 9, and connects the second pressure chamber _S2 to the first pressure chamber _S1 when the valve is opened and to the upstream side of the valve seat 7 when the valve is closed. It is configured to do so.

The atmosphere opening channel 21 is formed in the second case divided part _A2 by communicating with the third pressure chamber _S3 , and the third pressure chamber
It is configured so that the atmospheric pressure of _S3 can be applied to the diaphragm 5 as a valve closing force.

Auxiliary diaphragm 11 and second case division part
A pressurizing flow path 22 connecting the second pressure chamber S ₂ and the third pressure chamber S ₃ is formed in A ₂ , and the operation valve 17 that is switched and operated by the electromagnetic operation section 18 is connected to the second case divided part.
A ₂ is attached to the air release passage 21 and the pressurization passage 22 so that a non-blocking state in which only the former 21 is opened and a blocking state in which only the latter 22 is open can be selected by the operating valve 17. The operating valve 17 is configured to automatically switch from a non-shutoff state to a shutoff state when an emergency situation occurs, based on a signal from a detector B that detects an emergency situation such as an earthquake, flame, or gas leak. It has been done.

Gauge pressure P on the upstream and downstream sides of the valve seat 7 during normal flow, reduced gauge pressure ΔP due to leakage on the downstream side of the valve seat 7, and valve closing force by the biasing means 14
F ₁ , the valve closing force F ₂ due to the gravity of the valve body 8, the effective area a ₁ of the diaphragm 5, and the area a ₂ of the diaphragm portion 5a facing the second pressure chamber S ₂ are calculated using the following formula P×(a ₁ − _{a 2} )＞F ₁ +F ₂ ＞(P−ΔP)×(a ₁ −
_a2 ), and is configured to operate as follows.

[During normal flow]

As shown in FIG. 1, when the operating valve 17 opens the atmospheric release channel 21 and closes the pressurizing channel 22, the gauge pressure in the third pressure chamber _S3 becomes zero and the gauge pressure in the second pressure chamber S The gauge pressure of ₂ is almost P, and the valve opening force is 1st.
P× due to pressure from pressure chamber S ₁ to diaphragm 5
(a ₁ − _{a 2} ), and the valve closing force is F ₁ + F ₂ due to the urging force and gravity.
Therefore, the valve opening force becomes larger than the valve closing force, and the valve body 8 is maintained open.

[When a leak occurs]

In the state shown in FIG. 1, if a leak occurs on the downstream side of the valve seat 7 and the pressure decreases by the gauge pressure ΔP,
The valve opening force decreases to (P - ΔP) x (a ₁ - a ₂ ), and the valve closing force does not change at F ₁ + F ₂ , so if the valve closing force is larger than the valve opening force, , the valve body 8 is closed as shown in FIG.

When the valve body 8 is fully closed, the pressure on the upstream side of the valve seat 7 is transferred to the second pressure chamber S ₂ by the pressure guiding hole 12.
, the gauge pressure in the first pressure chamber S ₁ becomes almost zero, and the valve opening force is P×a ₃ due to the pressure from the opening of the valve seat (area a ₃ ) to the diaphragm 5. ₂
Since the valve closing force due to the pressure is P×a ₂ and a ₂ >a ₃ , the valve body 8 is maintained closed by the force of P×(a ₂ −a ₃ )+F ₁ +F ₂ .

[When an emergency situation occurs]

As shown in Fig. 3, the detector B and the electromagnetic operation section 1
8 automatically closes the operation valve 17 to the pressurizing channel 22.
is switched to open and the atmospheric release flow path 21 is closed, and the pressure on the downstream side of the valve seat 7 is applied from the pressure guiding hole 12, the second pressure chamber S ₂ , and the pressurization flow path 22 to the third pressure chamber S ₃ . , the gauge pressure on both sides of the diaphragm 5 becomes approximately P over the entire area, and therefore the valve body 8
is closed by the force F ₁ + F ₂ .

Then, when the valve body 8 is fully closed, the upstream pressure of the valve seat 7 is applied from the pressure guiding hole 12, the second pressure chamber S ₂ , and the pressurizing flow path 22 to the third pressure chamber S ₃ , and The gauge pressure in pressure chamber S ₂ and third pressure chamber S ₃ is approximately P,
The gauge pressure in the first pressure chamber S ₁ becomes almost zero as the fluid flows out, the valve opening force is P×a ₃ due to the pressure from the opening of the valve seat 7 to the diaphragm 5, and the valve closing force is P×a ₁ +
Since F ₁ + F ₂ and a ₁ > a ₃ , the valve body 8 is P×
The valve is kept closed by the force of (a ₁ − a ₃ ) + F ₁ + F ₂ .

[At reset]

When the reset valve 15 is opened with the valve 8 fully closed, and the air release passage 21 is opened using the operation valve 17, so that there is no outflow on the downstream side of the valve seat 7, the pressure in the first pressure chamber _S1 increases. However, the valve body 8 is opened due to an increase in the opening force of the first pressure chamber S ₁ and a decrease in the closing force of the third pressure chamber S ₃ .

If the flow path is open on the downstream side of the valve seat 7, even if the reset valve 15 is opened, the pressure in the first pressure chamber _S1 will not increase much, and the fully closed state of the valve body 8 will be maintained, and the can prevent fluid from flowing out.

[Another example]

Next, another embodiment will be described.

A spring may be used instead of the weight 14, and these are referred to as biasing means 14.

The operating means of the operation valve 17 can be changed as appropriate, for example, as shown in FIG. As shown in FIG. 3, the operation valve 17, which is biased to be in the closed state by a spring 16', is formed so that it can be maintained in the non-closed state by a rotary operation type cam type stopper 19, and the stopper 19 can be manually operated. It may also be configured such that switching between the non-blocking state and the blocking state can be performed with.

[Brief explanation of the drawing]

1 to 3 are sectional views showing an embodiment of the present invention, in which FIG. 1 shows the state during normal flow, FIG. 2 shows the state when leakage occurs, and FIG. 3 shows the state during emergency shutoff. FIG. 4 is a sectional view showing another embodiment of the present invention. 5 to 7 show conventional examples, with FIG. 5 showing normal flow, FIG. 6 showing leakage, and FIG. 7 showing emergency shutoff. FIG. 8 is a sectional view showing a comparative example. 5... Diaphragm, 5a... Diaphragm part, 7... Valve seat, 8... Valve body, 11... Auxiliary diaphragm, 12... Pressure guiding hole, 14... Biasing means, 17... Operation valve, 21... Atmosphere opening flow path,
22... Pressurization channel, A ₁ ... First case divided portion, A ₂ ... Second case divided portion, S ₁ ... First pressure chamber, S ₂ ... Second pressure chamber, S ₃ ... Third pressure chamber.

Claims (1)

[Scope of claims for utility model registration] Cases A ₁ and A ₂ are divided into the first case divided part A ₁ and the second case.
A diaphragm 5 is provided which divides the inside of the cases A _{1 and} A ₂ into two, and cooperates with the diaphragm 5 to create a flow path and first pressure chamber S ₁ on the downstream side of the valve seat. A valve seat 7 is provided in the first case division part A ₁ forming the valve seat 7 with its opening facing the diaphragm 5 , and a valve body 8 is provided in the first case division part A 1 forming the valve seat 7 .
A biasing means 14 is disposed on the downstream side of the diaphragm 5 and acts on the valve element 8 to bring it closer to the valve seat ₇ . 5 is provided with an auxiliary diaphragm 11 that partitions the space formed by the diaphragm 5 into a second pressure chamber S ₂ and a third pressure chamber S ₃ facing the diaphragm 5. are respectively connected to the second case divided portion _A2 , and a portion 5 of the diaphragm 5 facing the second pressure chamber _S2 .
A is formed to have a larger area than the opening of the valve seat 7, and the pressure guiding hole 12 communicating with the second pressure chamber _S2 is inserted into the valve body 8 with its inlet facing the opening of the valve seat 7. and a pressurizing channel 2 formed in the diaphragm 5 and connecting the second pressure chamber _S2 and the third pressure chamber _S3 .
2 is formed in the auxiliary diaphragm 11 and the second case division part _A2 , and an atmosphere opening passage 21 connecting the third pressure chamber _S3 to the atmospheric space is formed in the second case division part _A2. , an operation valve 17 that selectively opens the atmosphere opening flow path 21 and the pressurization flow path 22 is provided in the second case divided portion _A2 , and the operation valve 17 is provided on the upstream and downstream sides of the valve seat 7 during normal flow. gauge pressure P at , reduced gauge pressure ΔP due to leakage on the downstream side of the valve seat 7, valve closing force F ₁ by the biasing means 14, and valve closing force due to the gravity of the valve body 8.
F ₂ , the effective area a ₁ of the diaphragm 5, the second
Area of the diaphragm portion 5a facing the pressure chamber _S2
a ₂ is calculated using the following formula: P×(a ₁ − a ₂ )>F ₁ +F ₂ >(P−ΔP)×(a ₁ −
a ₂ ) automatic shutoff valve configured to meet the requirements of