LP gas container valve against disasters

Abstract: A valve (1) incorporating a system satisfying the conditions required for a high-pressure gas container valve and previously preventing an accident such as a fire or explosion which occurs in such disasters as an earthquake. A ball (20) movable between its stationary position in normal operation and its gas cutting off position in abnormal operation is provided in a gas passage (2) between a branching point leading to a safety valve and a closing valve (5); a taper portion (2a) having a passage narrowed toward the closing valve (5) is provided in the gas passage (2) in the vicinity of the gas cutting off position such that the ball (20) abuts against the taper portion (2a) to close the gas passage (2) at the time of an abnormal outflow of gas. Further, in the state where the container valve is shut down, a terminal end (5a) of a seat packing of the closing valve (5) abuts against the ball to form a gap between the taper portion (2a) and the ball (20). A ball receiver (21) in the form of an umbrella frame raised toward the periphery thereof is provided at the stationary position in normal operation of the ball.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to gas container valves, and more particularly relates to an LP gas container valve capable of meeting disasters for preventing an abnormal outflow of gas due to a disaster from occurring when the container valve is fully opened in its state of normal use. 2. Description of the Related Art A condition required for valves to be mounted on an inlet/outlet of a container for a high-pressure gas such as an LP gas container is its capability of satisfactory carrying out such typical operations as charging of gas, recovery of a residual gas and a gas blow test. In addition, as a counter measure against such disasters as an earthquake or fire, other requirements include prevention of a secondary disaster resulting from discharging of a large amount of gas due to a collapsed house or a damage on gas supplying facility and prevention of gas discharge even at the time of the gas cylinder falling down so as not to cause an explosion of the cylinder even if the container is exposed to a flame in a fire. However, the technology completely satisfying these requirements has not yet been developed. Of those described above, while a safety valve is provided to prevent an explosion of the container due to an abnormally elevated pressure within the container, it is incapable of preventing discharge of a large amount of gas due to an damage on the gas supplying facility. As a counter measure against a danger of fire, explosion, etc., there are those inserting a cutoff valve to be actuated as a result of sensing an abnormal outflow of gas between the valve and a destination of gas supply or incorporating into the valve a sensor mechanism for sensing an inclination of the gas container or shaking of an earthquake and a gas cutting off section to be actuated by the sensor. Generally, in the case where LP gas cylinder or the like is provided at a consumer's house, etc., a high-pressure collective automatic switching device is used and all of the individual container valves are fully opened. Accordingly, if a breakage occurs at a some point on the gas supplying facility due to an occurrence of earthquake or an unexpected accident, etc., it is very dangerous because of a large amount of gas being discharged from the point of breakage. In such a case, the gas supply beyond the valve must be instantaneously shut down. In a system using a separate cut-off device provided as an attached component part at the outlet of a conventional container valve, its mounting and fixing to the surrounding structure is more complicated comparing to a system where only a conventional valve is used, even if the device itself is simple and securely operable. The level of safety is correspondingly lowered and the cost of the facility is higher. Further, most of those systems incorporating an anti-earthquake gas cutoff mechanism into the gas container valve have not yet met all the objective conditions. For example, there is a system where a tapered portion having a passage narrowed toward an outlet is provided in the gas passage between the gas container body and the closing/opening section of the valve and a ball is provided as movable in the passage. When the gas flowing rate is abnormally increased, the ball is abutted against the taper portion to cut off the gas. However, any such proposal using a gas cutting off ball is either without a safety valve on the valve or, even with a safety valve, is unstable and insecure in operation because the stationary position in normal operation of the ball is located in the gas passage on the side toward the gas container body from the branching point leading to the safety valve. In particular, there is a danger of explosion with the system without a safety valve due to its incapability in responding to an abnormally elevated gas pressure for example at the time of fire. It lacks an indispensable condition as a high-pressure gas container valve. In the system where the normal stationary position of the ball is located toward the gas container body, the ball is drawn by suction toward the safety valve from the branching point when the safety valve is actuated, thereby closing the opening toward the safety valve and not allowing the normal operation thereof. Even if the passage leading to the safety valve is widened comparing to the conventional product in order to make it larger than the diameter of the ball, when the safety valve is actuated before the starting of an abnormal outflow of gas or when an abnormal gas outflow occurs in the state where the ball remains in a position toward the safety valve from the branching point as a result of the cylinder falling down with the safety valve facing down, it is impossible only by the flow of the gas to move the ball from that position toward the point for cutting off the abnormal outflow. There is thus a disadvantage that the purpose of cutting off the gas outflow cannot be achieved. SUMMARY OF THE INVENTION It is an object of the present invention to provide an LP gas container valve for meeting an emergency in natural disasters having a system incorporated in the valve which solves the above described problems to satisfy all the required conditions for a high-pressure gas container valve and, together with a safety valve, is capable of previously and securely preventing such accidents as a fire or explosion which may occur at the time of disaster such as an earthquake. To solve the above described problems, an LP gas container valve against disasters is provided in accordance with the present invention having, the container valve being mounted on a propane gas container and including a closing valve for opening/closing a gas passage leading a valve outlet and a safety valve to be actuated in response to an abnormal elevation of gas pressure, the LP gas container valve further comprising: a ball having a stationary position in normal state of operation and a gas cutting off position in abnormal state of operation within the gas passage from the gas container to the valve outlet where the ball is movable between the stationary position and gas cutting off position; and a taper portion provided in the gas passage in the vicinity of the gas cutting off position to narrow the passage toward the closing valve so that said ball abuts against the taper portion to close the gas passage at the time of an abnormal outflow of gas from the gas container toward the container valve outlet, characterised in that said ball is located between a branching point leading to the safety valve and the closing valve. Further, it is constructed so that, in the state where the closing valve is shut down, a terminal end of a seat packing of the closing valve abuts against the ball to form a gap between the tapered portion and the ball. Furthermore, a ball receiver in the form of an umbrella frame having a lower center portion for receiving the ball and a raised portion toward the surrounding thereof is provided in the gas passage at the stationary position in normal operation of the ball. Moreover, the safety valve is disposed so that a traveling distance,of 4 mm or more is provided between the stationary position in normal operation and the gas cutting off position in abnormal operation of the ball; the diameter of the ball is set to 8.17 mm to 10 mm and the minimum diameter of the taper portion is set to 7.5 to 8 mm, the caliber of the gas passage continuing to the taper portion being set to 13 mm or more. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 is a front sectional view showing an embodiment of the present invention. FIG.2 is a perspective view of external appearance of the embodiment of FIG.1. FIG.3 is a perspective view showing the embodiment of FIG.2 with a portion thereof being removed. FIG.4 illustrates operation (at the time of abnormal gas outflow) of the stop ball. FIG.5 illustrates operation (at the time of residual gas recovery) of the stop ball. FIG.6 illustrates an inoperable state due to an erroneous setting of the normal position of the stop ball. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the drawings. FIG.1 is a front sectional view showing an embodiment of the present invention. FIG.2 is a perspective view showing an external view of the embodiment of FIG.1. FIG.3 is a perspective view sectioned partly showing in section only certain portions of the perspective view of external appearance of FIG.2. Here, FIG.1 shows a closing valve 5 in its closed position and FIG.3 shows the closing valve 5 in its opened position. Referring to FIGs.1 to 3, a valve body 1 is screwed into a female thread in a gas outlet/inlet of a cylinder (not shown) to be coupled thereto by means of a gas cylinder coupling male screw 1a. What is denoted by numeral 2 is a gas passage from a valve inlet 1b to a valve outlet 3b. A high-pressure pipe connecting portion 3 is coupled to a gas supplying high-pressure pipe (not shown) through a female screw 3a. It should be noted that, in most cases, coupling to a high-pressure pipe is performed by screwing a left-handed screw using an attaching metal fixture by means of a high-pressure hose. What is denoted by numeral 5 is a closing valve for shutting down the gas passage 2. The closing valve 5 may be moved up and down by a handle 8 which is coupled thereto through a valve stem 6 and a spindle 7. A gland nut 9 has a female screw portion 9a thereof engaged with a male screw 6a of the valve stem 6. A safety valve 10 is pressed against surface provided in a gas passage branch portion 2b leading to the safety valve by a spring 11 which is in contact with an inner side surface of a cap 12 at one end portion thereof, thereby closing the passage branch portion 2b. Since operation of the closing valve 5 and the safety valve 10 is identical with the like portion of a conventional valve, the relation between the two will not be described. Although, as shown in FIG.2, the present embodiment has little difference in external appearance from a conventional gas cylinder valve, a ball (hereinafter referred to as stop ball) 20 for cutting off the gas at the time of an abnormal outflow of gas by abutting against an inclined surface 2a which narrows the gas passage immediately before the closing valve 5 is inserted into the gas passage 2 as shown in FIGs.1 and 3. A ball receiver 21 is provided to support the stop ball 20 in normal position, its fixed position is located as shown in FIGs.1 and 3 toward the closing valve 5 from the branching point leading to the safety valve 10 within the gas passage 2. Although the ball receiver 21 can have any shape as far as a relatively large area for allowing passage of gas is provided and resistance at the time of passing of gas is small, it is, in the present embodiment, similar to the frame of an umbrella opened upside down. It is formed into a cross having a lowered center portion and raised toward the surrounding thereof. It should be noted that, in order to fully utilize the function of the stop ball 20, the dimension from the terminal end of the seat packing of the closing valve to the center line of the safety valve is selected to 13 mm to 16 mm, and, in the present embodiment, the disposed position of the safety valve 10 is lowered by about 10 mm comparing to a conventional like product. By disposing the safety valve at this position, the distance between the closing valve and the safety valve is minimized to an extent possible to achieve a reduction in size of the valve body, and a minimum (4 mm or more) distance is secured between the stationary position in normal operation and the gas cutting off position in abnormal operation of the ball so as to secure the cutting off of the gas passage by the ball. Further, the diameter of the safety valve is increased comparing to the conventional product to be about 10 mm in the present embodiment while it has been about 6.7 mm in the conventional product. Accordingly, since the opening area of the safety valve is increased to about two times that of the conventional product, the safety level against a container explosion at the time of disaster is much higher than the conventional product. FIG.4 illustrates in section certain portions around the stop ball 20, where the position in normal operation of the stop ball 20 is indicated by a two-dot chain line and its position when actuated is indicated by a solid line. The stop ball 20 may be designed so that, when the closing valve 5 is opened as shown in FIG.1, it is not floated at a generated gas amount (gas flow) of 4.5 kg/H or less but is floated at a gas flow of 5 to 10 kg/H to close the gas passage 2. It should be noted that, in the case of automatically switching between two LP gas cylinders for the general consumer, the gas flow at the time of using a single 50-kg container is normally 2 to 3 kg/H or less even for an equipment consuming a large amount; it is 4 kg/H or less even for a maximum use in a short period of time. In the case of the present embodiment, when the gas flow has become 8 kg/H or higher, the stop ball 20 is floated as a result of receiving the gas pressure so as to automatically close the gas passage 2 as shown in FIG.4 to stop the gas flow. For restoration of the stop ball 20 which has once been actuated, it suffices to close the closing valve 5. By gradually closing the closing valve 5 after removing the cause of abnormal outflow of gas or confirming a safe environment even with an abnormal outflow, a terminal end portion 5a of the closing valve 5 contacts and pushes down the stop ball 20 to open the gas passage 2 which has been shut down. When the closing valve 5 is further closed to complete the closing of the closing valve 5, the state of FIG.1 is restored. Further, while operation for a blow and recovery of residual gas is necessarily performed in an LP gas charging facility and a container inspection facility, it suffices in that case to bring the closing valve 5 to its half-opened state. FIG.5 illustrates certain portions in section showing the half-opened state of the closing valve 5. Even if a significant amount of gas is discharged in a short time period in a blow and residual gas recovery operation, the stop ball 20 does not close the gas passage 2 due to an interference by the terminal end portion 5a of the closing valve 5 which is half-opened. Accordingly, the blow or residual gas recovery operation can be complete almost at the rate of a fully opened valve. The reason for setting the stationary position in normal operation of the stop ball 20 to a position toward the closing valve 5 from the branching point leading to the safety valve 10 in the gas passage is as follows. The case is now considered of the stationary position in normal operation of the stop ball 20 being provided as shown in FIG.6 toward the inlet 1a at the cylinder coupling portion. There is a possibility which cannot be ignored that the stop ball 20 closes the safety valve 10 as shown in FIG.6 or is at a position toward the safety valve 10 for some reason such as an activation of the safety valve 10 before the occurrence of abnormal outflow of gas or falling down of the cylinder with the safety valve 10 facing down. If the stop ball 20 completely closes the branch passage to the safety valve 10, the safety valve 10 is of no use at all. Further, if an abnormal outflow of gas occurs in the state where the stop ball 20 remains at a position toward the safety valve 10, only the main stream of gas passes through the center portion of the gas passage 2 and it is impossible to cause the stop ball to escape from the position as shown in FIG.6. Accordingly, there occurs a possible problem of being unable to cut off an abnormal outflow of gas. The problem of such disadvantage is completely eliminated by setting the stationary position in normal operation of the stop ball 20 in the gas passage 2 toward the side of the closing valve 5 from the branching point leading to the safety valve 10. As has been described in detail above, according to the present invention: a ball hall including a stationary position in normal state of operation and a gas cutting off position in abnormal state of operation is provided between the branching point leading to a safety valve and the closing valve within a gas passage extended from a gas container to a container valve outlet; a ball is provided as movable within the ball hall; a taper portion having a passage narrowed toward the closing valve is provided in the gas passage in the vicinity of the gas cutting off position such that the ball abuts against the taper portion to close the gas passage when an abnormal gas outflow occurs from the gas container toward the container valve outlet. An advantage is thereby achieved that it is possible to incorporate into the valve a system capable of previously preventing a fire or such accident as an explosion which may occur at the time of disasters such as an earthquake. Accordingly, while an LP gas container provided at the place of a consumer has conventionally been with a continuous danger as it is used in the state where the valve of the container is fully opened, such problem can be simply and totally eliminated by using the container valve of the present invention. Further, based on the construction where the terminal end of seat packing of the closing valve abuts against the ball in the state where the closing valve is closed so as to form a gap between the taper portion and the ball, there is an advantage that a blow test as well as a gas charging operation and residual gas recovery operation are efficiently carried out, which are necessarily performed at an LP gas charging facility and container inspection facility and which are considered as a necessary condition by those skilled in the art.

Claims: An LP gas container valve (1) against disasters serving as a container valve mounted on a propane gas container including a closing valve (5) for opening/closing a gas passage (2) leading to a valve outlet (3b) and a safety valve (10) to be actuated in response to an abnormal elevation of gas pressure, the LP gas container valve further comprising: a ball (20) having a stationary position in normal state of operation and a gas cutting off position in abnormal state of operation within the gas passage (2) from said gas container to the valve outlet (3b), said ball (20) being movable between said stationary position and gas cutting off position; and a taper portion (2a) provided in the gas passage (2) in the vicinity of said gas cutting off position to narrow the passage toward said closing valve (5); and said ball (20) abutting against said taper portion (2a) to close the gas passage (2) at the time of an abnormal outflow of gas from said gas container toward the valve outlet (3b), characterised in that said ball (20) is located between a branching point leading to said safety valve (10) and said closing valve (5). An LP gas container valve against disasters according to claim 1, wherein, when the closing valve (5) is shut down, a terminal end (5a) of a seat packing of the closing valve abuts against the ball (20) to form a gap between the taper portion (2a) and the ball. An LP gas container valve against disasters according to claim 1 or 2 wherein a ball receiver (21) in the form of an umbrella frame having a lower center portion for receiving the ball (20) and a raised portion toward the surrounding thereof is provided in the gas passage (2) at the stationary position in normal operation of the ball. An LP gas container valve against disasters according to any of claims 1 to 3 wherein the safety valve is disposed so as to provide a traveling distance of 4 mm or more between the stationary position in normal operation and the gas cutting off position in abnormal operation of the ball. An LP gas container valve against disasters according to any of claims 1 to 4 wherein: the diameter of the ball (20) is set to 8.17 mm to 10 mm; the minimum diameter of the taper portion (2a) is set to 7.5 to 8 mm; and the caliber of the gas passage (2) continuing to the taper portion is set to 13 mm or more.

Inventors: INAYOSHI TAMIAKI, INAYOSHI, TAMIAKI
Applicants: AICHI KOATSU CO LTD, AICHI KOATSU CO., LTD.
Application year: 1996
Main classification: F16K11
IPC codes: F17C13, F16K1