JP2005054876A - Liquefied petroleum gas storage tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure the safety of an LP gas storage tank when a heat exchanger is installed in a liquefied petroleum gas (hereinafter, referred to as "LP") storage tank. <P>SOLUTION: An LP gas storage tank 1 to store LP gas has a heat exchanger 2 disposed in the LP gas storage tank 1, a heat source unit 3 to heat fluid for the heat exchanger 2 and feed the fluid in the heat exchanger 2, a gas pressure gage 5 to measure the petroleum gas pressure in the LP gas storage tank 1, and a heat source unit control panel 6 to stop the heat source unit 3 when the pressure of petroleum gas in the LP gas storage tank 1 measured by the gas pressure gage 5 is increased to a predetermined value. In addition, the heat exchanger 2 has pipes and a supporting plate to support base portions of the pipes, and the supporting plate is attachably/detachably fixed to the LP gas storage tank 1 via a sealant by bolts or the like outside the LP gas storage tank 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an LP gas storage tank for storing liquefied petroleum gas (hereinafter referred to as “LP gas”), and more particularly to an LP gas storage tank equipped with safety equipment.

The LP gas storage tank stores liquefied LP gas under a pressure that liquefies LP gas at room temperature. When the LP gas is taken out from the LP gas storage tank, the LP gas storage tank is cooled because the vaporization heat is absorbed when the LP gas changes from a liquid to a gas. For this reason, when a large amount of LP gas is used or when it is used for a long period of time, the temperature of the LP gas storage tank is significantly lowered due to the heat of vaporization, and it becomes difficult to vaporize and take out the LP gas. For this reason, a heat exchanger is disposed in the LP gas storage tank, and the LP gas storage tank is warmed by the heat exchanger, so that the LP gas stored in the LP gas storage tank can be easily taken out (for example, Patent Document 1). ). FIG. 10 shows this conventional LP gas storage tank 50. Here, a coiled heat exchanger 51 is arranged in the LP gas storage tank 50, and a pipe 52 is connected to the heat exchanger 51. For this reason, by sending warm water or the like from the pipe 52 to the heat exchanger 51, the LP gas storage tank 50 can be warmed to maintain the temperature at a predetermined value or higher, and the petroleum gas can be taken out from the LP gas storage tank 50.
However, in the above-described conventional LP gas storage tank 50 with a built-in heat exchanger 51, hot water heated simply using the exhaust heat of a micro gas turbine using petroleum gas as fuel is supplied to the heat exchanger 51 via a pipe 52. There was no means to ensure the safety of the entire device.
JP 2003-97351 A

  Therefore, the problem to be solved by the present invention is to maintain the safety of the LP gas storage tank incorporating the heat exchanger.

In order to solve the above-mentioned problem, the invention described in claim 1 is an LP gas storage tank for storing LP gas, a heat exchanger disposed in the LP gas storage tank, and a fluid for heating the heat exchanger. The heat source device for sending the gas into the heat exchanger, the gas pressure gauge for measuring the oil gas pressure in the LP gas storage tank, and the oil gas pressure in the LP gas storage tank measured by the gas pressure gauge has increased to a predetermined value. A LP gas storage tank comprising a heat source device control panel for sometimes stopping the heat source device.
As a result, the heat source heats the fluid for the heat exchanger arranged in the LP gas storage tank and sends the fluid into the heat exchanger, and the oil gas pressure in the LP gas storage tank measured by the gas pressure gauge is predetermined. When the temperature rises to the value, the heat source device control panel stops the heat source device, so that it is possible to prevent the oil gas pressure in the LP gas storage tank from rising beyond a predetermined value.

Further, the invention according to claim 2 is the invention according to claim 1, wherein the heat exchanger has a pipe and a support plate for supporting a base portion of the pipe, and the support plate is outside the LP gas storage tank, and the LP gas storage tank. The LP gas storage tank is detachably fixed by bolting or the like through a sealing material.
Thereby, since the said heat exchanger can be attached or detached to a LP gas storage tank, the maintenance and inspection of the said heat exchanger become easy.

Furthermore, the invention according to claim 3 is the invention according to claim 1, wherein a part of the pipe connected to the outlet side of the heat exchanger is made to be a flexible pipe that can be expanded and contracted, and the state in which the flexible pipe is extended is detected. The LP gas storage tank is characterized in that a switch is provided, and a signal indicating that the switch detects the extended state of the flexible pipe is sent to the monitoring center.
As a result, when the fluid in the heat exchanger freezes, the volume of the fluid expands, so that the stretchable flexible pipe constituting a part of the pipe connected to the outlet side of the heat exchanger extends. Furthermore, since the switch detects this extended state and this detection signal is sent to the monitoring center, the monitoring center can monitor the occurrence of this state.

Further, the invention according to claim 4 is the invention according to claim 1, wherein the recovery tank for recovering the fluid that has passed through the heat exchanger, and the petroleum gas leaked from the LP gas storage tank into the heat exchanger are the A gas leak detector for detecting the oil gas when it is carried into the recovery tank together with the fluid and leaks, and a first valve means for opening and closing a pipe connecting the heat exchanger and the recovery tank, The gas leak detector controls the heat source device control panel when the petroleum gas is detected, stops the operation of the heat source device, and connects a pipe connecting the heat exchanger and the recovery tank. The LP gas storage tank is characterized by being closed by one valve means.
Thereby, the fluid that has passed through the heat exchanger in the recovery tank is recovered, and the oil gas leaked from the LP gas storage tank into the heat exchanger is carried into the recovery tank together with the fluid and leaked When the gas leak detector detects this petroleum gas, the gas leak detector controls the heat source device control panel to stop the operation of the heat source device, and the heat exchanger and the recovery tank are Since the pipe to be connected is closed by the first valve means, it is possible to prevent the oil gas from leaking by preventing the fluid from flowing through the pipe immediately when the oil gas leaks.

Furthermore, the invention according to claim 5 is the invention according to claim 1, wherein the temperature of the petroleum gas in the LP gas storage tank is set to a second valve means for opening and closing a tap water pipe for sending tap water to the heat exchanger. A thermometer for measuring is provided, and when the temperature of the petroleum gas in the LP gas storage tank measured by the thermometer rises to a predetermined value, the second valve means opens the tap water pipe. LP gas storage tank.
Thereby, when the temperature of the petroleum gas in the LP gas storage tank measured by the thermometer rises to a predetermined value, the second valve means opens the pipe for tap water, so that the tap water is contained in the heat exchanger. The temperature of the LP gas storage tank can be lowered.

Since the invention according to claim 1 can prevent the oil gas pressure in the LP gas storage tank from rising beyond a predetermined value, the safety of the LP gas storage tank can be maintained.
Furthermore, the invention according to claim 2 can maintain the safety of the LP gas storage tank because the heat exchanger can be easily maintained and inspected together with the effect of the invention described in claim 1.
Furthermore, the invention according to claim 3 automatically notifies the monitoring center of the frozen state of the fluid in the heat exchanger, together with the effect of the invention described in claim 1, and keeps the safety of the LP gas storage tank. be able to.
Furthermore, the invention described in claim 4 can prevent oil gas leakage from the heat exchanger in the LP gas storage tank and keep the safety of the LP gas storage tank together with the effect of the invention described in claim 1 above. Can do.
Furthermore, the invention described in claim 5 can prevent the temperature of the LP gas storage tank from rising excessively and maintain the safety of the LP gas storage tank together with the effect of the invention described in claim 1 above.

  The best mode for carrying out the present invention will be described below with reference to the drawings. 1 shows a first embodiment of the present invention, FIG. 2 shows a second embodiment, FIG. 3 shows a third embodiment, and FIG. 4 shows a fourth embodiment. 5 shows a means for attaching the heat exchanger to the LP gas storage tank, FIG. 6 shows a method for removing the heat exchanger from the LP gas storage tank, and FIG. 7 shows the internal structure of the heat source device for sending fluid to the heat exchanger. FIG. 8 shows the internal structure of the flexible tube connected to the outlet side of the heat exchanger, and FIG. 9 shows the operating state of the flexible tube.

As shown in FIG. 1, an LP gas storage tank 1 for storing LP gas heats a heat exchanger 2 disposed in the LP gas storage tank 1 and a fluid (for example, a hot liquid of antifreeze liquid) serving as a heat exchange medium. The heat source device 3 for sending this fluid into the heat exchanger 2 via the check valve 17, the gas pressure gauge 5 for measuring the oil gas pressure in the LP gas storage tank 1, and the LP gas measured by the gas pressure gauge 5 A heat source device control panel 6 is provided to stop the heat source device 3 when the oil gas pressure in the storage tank 1 rises to a predetermined value. When the oil gas pressure in the LP gas storage tank 1 measured by the gas pressure gauge 5 reaches a lower limit pressure necessary for supplying the oil gas, the heat source device control panel 6 operates the heat source device 3. Further, the gas pressure gauge 5 may be of a type that measures the temperature of petroleum gas based on the correlation between pressure and temperature, which is a characteristic of petroleum gas, and converts it into pressure.
Further, a pressure gauge 22 for measuring the pressure of the fluid discharged from the heat exchanger 2 is disposed in the pipe 4 b on the outlet side of the heat exchanger 2, and the pipe 4 b between the downstream side of the pressure gauge 22 and the heat source unit 3. A valve 23 is connected to the. When the heat source 3 is stopped and the valve 23 is closed, the pressure of the fluid discharged from the heat exchanger 2 can be monitored by the pressure gauge 22, so that petroleum gas leaks from the LP gas storage tank 1 to the heat exchanger 2. Can be detected.

As shown in FIG. 5, the heat exchanger 2 has a U-shaped pipe 2a (the material of the pipe 2a is stainless steel having excellent corrosion resistance, for example) and a support plate 2b that supports the base of the pipe 2a. In a state where the pipe 2a is inserted into the opening 1b of the heat exchanger mounting portion 1a of the LP gas storage tank 1, the support plate 2b exchanges heat with the LP gas storage tank 1 via the sealing material 7a outside the LP gas storage tank 1. Further, the mounting plate 4c is fixed to the end portions of the piping 4a on the inlet side of the heat exchanger 2 and the piping 4b on the outlet side of the heat exchanger 2, and the mounting plate 4c is The support plate 2b and the mounting plate 4c are arranged on the outside of the support plate 2b via the sealing materials 7b, 7c, and 7d, and are detachably fixed to the heat exchanger mounting portion 1a by bolts 8 or the like.
Since the sealing material 7a is disposed so as to surround the periphery of the opening 1b, the space between the heat exchanger mounting portion 1a and the support plate 2b is kept airtight by the sealing material 7a. Further, since the sealing materials 7b and 7c are arranged so as to surround the connecting portion between the left piping 2a and the piping 4b in the drawing, the connecting portion between the left piping 2a and the piping 4b in the drawing is hermetically sealed by the sealing materials 7b and 7c. It is kept in. Further, since the sealing materials 7c and 7d are arranged so as to surround the connecting portion between the right piping 2a and the piping 4a in the drawing, the connecting portion between the right piping 2a and the piping 4a in the drawing is hermetically sealed by the sealing materials 7c and 7d. It is kept in. As a result, the connection portion between the heat exchanger 2 and the pipes 4a and 4b is kept airtight. Further, since the sealing materials 7a, 7b, 7c and 7d are fitted in the grooves 2c formed in the support plate 2b, there is no possibility that the positions of the sealing materials 7a, 7b, 7c and 7d are shifted.
In addition, FIG. 6 has shown the state which removed the support plate 2b and the attachment plate 4c from the heat exchanger attachment part 1a.

  As shown in FIG. 7, the heat source device 3 includes a pump 13 that sends a fluid to the heat exchanger 2 and a heating unit 14 that heats the fluid in the pipe 4 a. The heating unit 14 is similar to a gas water heater, and heats the fluid in the pipe 4a to below 40 ° C. using a temperature sensor (not shown). As shown in FIG. 1, the oil gas taken out from the LP gas storage tank 1 is adjusted in pressure by the pressure regulator 9 and supplied to the heating unit 14 as fuel of the heat source device 3.

Furthermore, as shown in FIG. 1, a part of the pipe 4b connected to the outlet side of the heat exchanger 2 is made a flexible pipe 30 that can be expanded and contracted, and a proximity switch 40 that detects a state in which the flexible pipe 30 is extended is provided. The proximity switch 40 sends a signal that detects the extended state of the flexible tube 30 to the monitoring center via an NCU (transmission device) 41.
As shown in FIG. 8, the flexible tube 30 is disposed inside the housing 31, and the fixed end (one end) 32 of the flexible tube 30 is fixed to the housing 31 by a bolt 33, and the free end (others) of the flexible tube 30 is arranged. A magnet 35 is attached to the (end) 34. A proximity switch 40 is attached to the position of the casing 31 corresponding to the magnet 35.
As shown in FIG. 9, when the flexible tube 30 is extended, the magnet 35 approaches the proximity switch 40, so that the proximity switch 40 is activated and turned on, and an electrical signal indicating this ON state is an NCU 41 (see FIG. 1). ) And sent to the monitoring center.

The LP gas storage tank having the above configuration operates as follows.
The heat source 3 heats the fluid passing through the heat exchanger 2 disposed in the LP gas storage tank 1 and sends the fluid into the heat exchanger 2, and the gas pressure gauge 5 measures the inside of the LP gas storage tank 1. When the oil gas pressure rises to a predetermined value, the heat source device control panel 6 stops the heat source device 3, so that the oil gas pressure in the LP gas storage tank 1 can be prevented from rising beyond the predetermined value. .
Furthermore, since the heat exchanger 2 can be attached to and detached from the LP gas storage tank 1, it is not necessary for an operator to enter the LP gas storage tank 1 from a manhole (not shown) of the LP gas storage tank 1 when the heat exchanger 2 is maintained and inspected. Therefore, maintenance and inspection of the heat exchanger 2 are facilitated.
Furthermore, when the fluid in the heat exchanger 2 freezes and its volume expands, the volume of this fluid expands, thereby expanding and contracting a part of the pipe 4b connected to the outlet side of the heat exchanger 2. When the possible flexible tube 30 is extended, the proximity switch 40 detects this extended state, and this detection signal is sent to the monitoring center, so that the occurrence of this state can be monitored at the monitoring center.

As shown in FIG. 2, Example 2 is obtained by adding a gas leak detector 12 to Example 1 of FIG. As shown in FIG. 7, the heat source device 3 is provided with a recovery tank 11 for recovering the liquid 10 as the fluid discharged from the heat exchanger 2. The arrow 10a indicates the direction in which the liquid 10 flows. A gas leak detector 12 is disposed in the vicinity of the collection tank 11. When the oil 10 leaked from the LP gas storage tank 1 to the heat exchanger 2 is mixed in the liquid 10 collected in the recovery tank 11, the mixed oil gas leaks from the opening of the recovery tank 11, and this The gas leak detector 12 detects the leaked petroleum gas.
As shown in FIG. 2, an electromagnetic valve control unit 15 controlled by the gas leak detector 12 is provided, and the electromagnetic valve 16 controlled by the electromagnetic valve control unit 15 is connected to the outlet side of the heat exchanger 2. 4b. The electromagnetic valve control unit 15 and the electromagnetic valve 16 correspond to “first valve means” in claim 4. When the gas leak detector 12 detects the gas leak, the solenoid valve control unit 15 closes the solenoid valve 16. Further, at this time, the gas leak detector 12 controls the heat source device control panel 6 to stop the heat source device 3.
With this configuration, the LP gas storage tank 1 operates as follows.
When the liquid 10 that has passed through the heat exchanger 2 is recovered in the recovery tank 11, and the petroleum gas leaked from the LP gas storage tank 1 into the heat exchanger 2 is carried into the recovery tank 11 together with the fluid and leaks. Moreover, when the gas leak detector 12 detects the leaked oil gas, the liquid 10 can be prevented from flowing immediately in the pipe 4b, thereby preventing the oil gas leak.

As shown in FIG. 3, the apparatus which sends a tap water to the heat exchanger 2 is added to Example 2 of FIG. Specifically, it is as follows.
A thermometer 21 for measuring the temperature of the petroleum gas in the LP gas storage tank 1 is added to the LP gas storage tank 1, and an electromagnetic valve control unit 20 controlled by the thermometer 21 is provided, and is controlled by the electromagnetic valve control unit 20. The electromagnetic valves 18 and 19 are provided. The electromagnetic valve control unit 20 and the electromagnetic valve 19 correspond to “second valve means” in claim 5. The solenoid valve 18 is a three-way solenoid valve and is connected to the pipe 4b on the outlet side of the heat exchanger 2, and the solenoid valve 19 connects the water source to the pipe 4a between the check valve 17 and the heat exchanger 2. It is arranged to do.
Thereby, when the temperature of the petroleum gas in the LP gas storage tank 1 measured by the thermometer 21 rises to a predetermined value, the electromagnetic valve control unit 20 operates the electromagnetic valve 18 to heat the heat source 3 from the heat exchanger 2. The pipe 4b is closed and the electromagnetic valve 18 can be drained directly, and the solenoid valve 19 is opened and the tap water flows into the heat exchanger 2 via the pipe 4a. The temperature of LP gas in 1 can be lowered. And the tap water poured into the heat exchanger 2 is drained from the solenoid valve 18.

  As shown in FIG. 4, the fourth embodiment is a combination of the first to third embodiments (see FIGS. 1 to 3). For this reason, the fourth embodiment operates by combining the operations of the first to third embodiments.

  In each of the above embodiments, the LP gas storage tank 1 has a vertical bulk shape, but is not limited thereto, and may have a horizontal bulk shape. Moreover, although the heat exchanger 2 is installed in the LP gas storage tank 1 from the lower end of the LP gas storage tank 1, the heat exchanger 2 is not limited thereto, and is installed in the LP gas storage tank 1 from the lateral end of the LP gas storage tank 1. It may be. Further, the proximity switch 40 is used. However, the present invention is not limited to this, and any switch that can detect the extension of the flexible tube 30 may be used.

  The present invention increases the safety of the LP gas storage tank for storing LP gas, and is therefore useful in industries using LP gas.

It is explanatory drawing which shows Example 1 of this invention. It is explanatory drawing which shows Example 2 of this invention. It is explanatory drawing which shows Example 3 of this invention. It is explanatory drawing which shows Example 4 of this invention. It is sectional drawing which shows the means to attach a heat exchanger to the LP gas storage tank of this invention. It is explanatory drawing which shows the method of removing a heat exchanger from the LP gas storage tank of FIG. It is explanatory drawing which shows the internal structure of the heat source device which sends a fluid to the heat exchanger of each said Example. It is sectional drawing which shows the internal structure of the flexible tube connected to the exit side of the said heat exchanger. It is sectional drawing which shows the operation state of the said flexible pipe | tube. It is explanatory drawing which shows the LP gas storage tank of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid petroleum (LP) gas storage tank 2 Heat exchanger 2a Piping 2b Support plate 3 Heat source device 4a, 4b Piping 5 Gas pressure gauge 6 Heat source device control panel 7a Sealing material 8 Bolt 11 Recovery tank 12 Gas leak detector 15 Solenoid valve control Part (first valve means)
16 Solenoid valve (first valve means)
18 Solenoid valve 19 Solenoid valve (second valve means)
20 Solenoid valve controller (second valve means)
21 Thermometer 30 Flexible pipe 40 Proximity switch (switch)

Claims (5)

In a liquefied petroleum gas storage tank that stores liquefied petroleum gas, a heat exchanger disposed in the liquefied gas storage tank, a heat source that heats the fluid for the heat exchanger and sends the fluid into the heat exchanger, and liquefaction Gas pressure gauge for measuring oil gas pressure in the oil gas storage tank, and heat source control for stopping the heat source apparatus when the pressure of the petroleum gas in the liquefied gas storage tank measured by the gas pressure gauge rises to a predetermined value A liquefied petroleum gas storage tank characterized by having a panel. 2. The liquefied petroleum gas storage tank according to claim 1, wherein the heat exchanger includes a pipe and a support plate that supports a base portion of the pipe, and the support plate is provided with a sealing material for the liquefied gas storage tank outside the liquefied gas storage tank. A liquefied petroleum gas storage tank, which is detachably fixed by bolting or the like. The liquefied petroleum gas storage tank according to claim 1, wherein a part of the pipe connected to the outlet side of the heat exchanger is a flexible pipe that can be expanded and contracted, and a switch that detects a state in which the flexible pipe is extended is provided. A liquefied petroleum gas storage tank characterized in that a signal indicating that the switch has detected an extended state of the flexible pipe is sent to a monitoring center. The liquefied petroleum gas storage tank according to claim 1, wherein a recovery tank that recovers the fluid that has passed through the heat exchanger, and the petroleum gas that has leaked from the liquefied gas storage tank into the heat exchanger are recovered together with the fluid. A gas leak detector for detecting the oil gas when leaked by being carried into the tank; and a first valve means for opening and closing a pipe connecting the heat exchanger and the recovery tank, the gas leak detection When the oil gas is detected, the device controls the heat source device control panel to stop the operation of the heat source device, and a pipe connecting the heat exchanger and the recovery tank is connected to the first valve means. A liquefied petroleum gas storage tank characterized by being closed. A liquefied petroleum gas storage tank according to claim 1, wherein the second valve means for opening and closing a tap water pipe for sending tap water to the heat exchanger, and a thermometer for measuring the temperature of the petroleum gas in the liquefied gas storage tank The liquefied petroleum gas storage tank, wherein the second valve means opens the tap water pipe when the temperature of the petroleum gas in the liquefied gas storage tank measured by the thermometer rises to a predetermined value. .

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