JP6130707B2 - Liquefied gas evaporator - Google Patents

Description

  The present invention relates to a liquefied gas evaporator that vaporizes a liquid phase liquefied gas and supplies it to a gas consuming device or the like.

  The liquefied gas such as LPG is continuously supplied to gas consuming equipment etc. after the liquid phase liquefied gas contained in a container such as a cylinder is led to the evaporator, vaporized and heated by the evaporator. Yes. For example, the evaporator described in Patent Document 1 includes an evaporation section in which a heat exchange channel is formed in a heat transfer member that is heated by a heat source such as an electric heater, and introduces a liquid-phase liquefied gas into the evaporation section. It is vaporized, heated to room temperature, and supplied to gas consuming equipment. In addition, a vaporization pressure adjustment valve is provided for controlling the amount of liquefied gas in the liquid phase flowing into the evaporation unit in accordance with fluctuations in gas consumption of the gas consuming device.

JP-A-11-114405

  In Patent Document 1, when the temperature of the evaporator is abnormally lowered due to a power failure or the like, there are various problems when liquid phase liquefied gas that does not vaporize is supplied to the gas consuming device side. A safety mechanism that urgently shuts off the vaporization pressure regulating valve has been proposed. However, in order to effectively and stably vaporize the liquefied gas in the liquid phase, no consideration is given to how to specifically control the temperature of the evaporation section.

  The problem to be solved by the present invention is to provide a liquefied gas evaporator having temperature control of an evaporation section capable of effectively and stably vaporizing a liquefied gas in a liquid phase.

In order to solve the above-described problems, a liquefied gas evaporator according to the present invention includes a heat transfer block in which a heat exchange channel for liquefied gas is formed in a vertical direction, a heat source inserted in the heat transfer block, and the heat transfer block. comprising a temperature sensor which is inserted into the heat block, and a temperature controller for controlling the heat generation of the heat source based on the detected temperature of the temperature sensor, the surface of the heat transfer block the upper end of the heat-exchange passage is opened A vaporized liquefied gas is discharged from an opening at the lower end of the heat exchange flow path, and an adjusted liquid phase liquefied gas is introduced into a pressure chamber provided to cover the evaporated surface. The temperature sensor is arranged between the heat source and the evaporation surface.

That is, a temperature sensor is inserted between the heat source (for example, an electric heater) and the evaporation surface and a temperature sensor is inserted into the heat transfer block to detect a temperature close to the evaporation surface. Then, the temperature controller adjusts the amount of heat of the heat source (for example, energization of the electric heater) so that the detected temperature of the heat transfer block at the part where the temperature sensor is inserted is within a set temperature range (for example, 35 ° C. to 46 ° C.). Control. By such temperature control, the temperature change of the evaporation surface can be reduced, so that stable evaporation ability with little change in the overall heat transfer coefficient can be maintained. Moreover, the closing pressure of the vaporization pressure control valve for supplying the liquid phase liquefied gas to the pressure chamber provided to cover the evaporation surface is also stabilized. As a result, the temperature change of the evaporation surface can be further reduced, and the temperature change width of the heat transfer block can also be reduced. In other words, since undershoot in which the temperature fluctuates downward by temperature control can be reduced, liquid phase liquefied gas can be effectively and stably vaporized. Moreover, in order to prevent the liquid phase liquefied gas from flowing out from the evaporator to the gas consuming device, etc., a liquid outflow prevention device is generally provided, but since the temperature control undershoot can be reduced, the liquid outflow prevention device A margin can be given to the operating temperature. That is, since the set temperature range of the temperature controller can be set to be low as a whole, the lifetime of the seal member and the electrical parts of the evaporator can be extended.

  Further, the heat transfer block is formed of an aluminum alloy casting, and a plurality of heat exchange passages are formed in parallel from the liquefied gas introduction side to the discharge side, and the heat exchange block is interposed between the heat exchange passages. It is preferable to disperse and insert electric heaters formed in one or a plurality of rods so as to be orthogonal to the heat exchange flow path. Thereby, the temperature distribution of the heat transfer block can be made uniform, and evaporation and heating of the liquid phase liquefied gas can be performed efficiently and stably. Furthermore, using a temperature sensor in which a thermocouple is housed in a rod-shaped protective pipe, the temperature sensor is positioned between the heat exchange flow paths and inserted into a heat transfer block between the electric heater as a heat source and the evaporation surface. be able to. Thereby, since the temperature of the part of the heat transfer block close to the evaporation surface can be detected, the temperature of the heat transfer block can be controlled more stably.

  ADVANTAGE OF THE INVENTION According to this invention, the liquefied gas evaporator provided with the temperature control of the evaporation part which can vaporize the liquefied gas of a liquid phase effectively and stably can be provided.

It is a fragmentary sectional view explaining the structure of one Example of the evaporator of this invention. It is sectional drawing explaining the structure of the vaporization pressure regulating valve of the Example of FIG. It is a diagram explaining the temperature control operation | movement of the Example of FIG.

  As shown in FIG. 1, an evaporator according to an embodiment of the present invention includes an evaporator 1, a temperature controller 50 provided on a side surface of the evaporator 1, and a vapor pressure adjustment provided on the top of the evaporator 1. And a valve 60. The evaporation part 1 has a heat transfer block 2 that is a heat medium formed of a metal material such as an aluminum alloy casting. In the heat transfer block 2, a plurality of heat exchange channels 3 are perforated in parallel from the upper side to the lower side in the drawing, and a plurality of rod-shaped electric heaters as heat sources are orthogonally arranged between the plurality of heat exchange channels 3. 4 and a bar-shaped temperature sensor 5 is inserted above the electric heater 4. The temperature sensor 5 is formed by accommodating a thermocouple in a rod-shaped protective tube. In the heat transfer block 2, an evaporation surface 6 is formed on the surface where the upper end of the heat exchange flow path 3 opens. The lower end of the heat exchange channel 3 is opened to a bottom space 7 formed in the lower part of the heat transfer block 2. A concave bottom member 9 that forms a vaporized gas chamber 8 together with the bottom space 7 is fixed to the lower surface of the heat transfer block 2.

  An outlet nozzle 10 for vaporized liquefied gas is communicated with the upper portion of the vaporized gas chamber 8 to supply the vaporized liquefied gas to a gas consuming device (not shown). A safety valve 12 is communicated with the outlet nozzle 10 via the original valve 11. Even if the gas consumption of the gas consuming device is suddenly stopped and the vaporization pressure regulating valve 60 is shut off, the safety valve 12 can be used even if the liquid-phase liquefied gas remaining in the evaporator is vaporized and the internal pressure rises. The internal volume is determined so as to be kept at a pressure less than the pressure at which the air begins to blow (for example, 0.693 MPa). On the other hand, a drain nozzle 14 having a drain valve 13 is communicated with the bottom of the vaporized gas chamber 8.

  The temperature controller 50 is certified as an explosion-proof electrical machine instrument, and includes a control unit that controls energization of the plurality of electric heaters 4, a temperature detection unit that obtains a detection temperature based on the output of the temperature sensor 5, and the like. It is formed with.

  As shown in FIG. 2, the vaporization pressure regulating valve 60 is attached so as to cover the evaporation surface 6 of the heat transfer block 2 by a pressure chamber 62 formed in the valve body 61. An adjustment valve 64 that adjusts the pressure in the pressure chamber 62 by introducing a liquefied gas in a liquid phase from an inlet nozzle portion 63 fixed to the side wall of the valve body 61 so as to face the pressure chamber 62 is provided. Further, the pressure chamber 62 communicates with the set pressure chamber 65 via the communication passage 62a. The set pressure chamber 65 is opened on the upper surface of the valve body 61, and a pressure setting portion 66 is provided to cover the opening of the set pressure chamber 65. The pressure setting unit 66 has a cylindrical case 67 fixed to the upper surface of the valve body 61, and a diaphragm 68 supported by an opening at the lower part of the case 67 is provided facing the set pressure chamber 65. . A stem 69 is suspended from the lower surface of the central portion of the diaphragm 68. The diaphragm 68 is urged toward the set pressure chamber 65 by the pressure adjusting spring 70. The upper end of the pressure adjusting spring 70 is provided in contact with the spring retainer 71, and the spring retainer 71 can adjust the set pressure by adjusting the screwing amount of the pressure adjusting screw 72. The stem 69 has a tip projecting from the pressure chamber 62 through a through hole 74 formed in a partition wall 73 between the set pressure chamber 65 and the pressure chamber 62. The gap between the through hole 74 and the stem 69 is slidably sealed by the seal member 75. A triangular movable piece 77 is rotatably provided by a pin 78 on a support member 76 suspended from the lower surface of the partition wall 73 on the pressure chamber 62 side. The tip of the stem 69 is in contact with one side of the movable piece 77.

  On the other hand, the regulating valve 64 is fixed to the valve body 61 by inserting an inlet nozzle portion 63 into a hollow portion 81 formed in a proximal end portion of a cylindrical main body portion 80 formed in a tapered shape. A small-diameter through hole 82 is bored from the distal end of the hollow portion 81 to the distal end of the main body portion 80. A step formed by the hollow portion 81 and the through hole 82 is a valve seat 83, and a valve body 84 that opens and closes the opening of the valve seat 83 is provided. The valve body 84 is fixed to a valve rod 85 inserted through the through hole 82 and is urged in the direction of the valve seat 83 by a spring 86 interposed between the valve body 84 and the distal end portion of the inlet nozzle portion 63. The tip of the valve rod 85 is provided in contact with one side of the movable piece 77. The side of the movable piece 77 with which the valve rod 85 and the stem 69 are in contact with each other is the side having the pin 78 in the rotational direction.

  The operation of the liquefied gas evaporator of this embodiment configured as described above will be described. The liquid liquefied gas is supplied from a liquefied gas container (not shown) to the regulating valve 64 via the inlet nozzle portion 63. After the evaporator is started and the temperature of the evaporation unit 1 rises to a predetermined temperature, when a liquid liquefied gas (for example, a pressure of 0.2 to 1.5 MPa) is supplied from the inlet nozzle unit 63 to the regulating valve 64, the ejection nozzle From 90, a liquid phase liquefied gas is ejected into the pressure chamber 62. The pressure in the pressure chamber 62 is adjusted to a set pressure (for example, 0.15 ± 0.04 MPa) by the cooperation of the control valve 64 and the pressure setting unit 66. The liquid-phase liquefied gas ejected into the pressure chamber 62 is instantaneously evaporated on the evaporation surface 6, heated to about room temperature through the heat exchange channel 3, and guided to the vaporized gas chamber 8. The liquefied gas introduced into the vaporized gas chamber 8 is supplied to a gas consuming device (not shown) through the outlet nozzle 10.

  When the pressure in the pressure chamber 62 becomes higher than the set pressure in the pressure setting section 66 due to a small amount of liquefied gas consumed by a gas consuming device or the like, or because the amount of evaporation on the evaporation surface 6 is large, etc. The pressure adjusting spring 70 is compressed by the pressure, and the diaphragm 68 is pushed up. As a result, the stem 69 is pushed up, the movable piece 77 rotates clockwise, the valve body 84 is urged toward the valve seat 83 by the spring 86 via the valve rod 85, and the liquid to the pressure chamber 62 is liquidated. The introduction of liquefied gas is interrupted.

  On the contrary, when the consumption amount of the liquefied gas increases or the pressure in the pressure chamber 62 becomes lower than the set pressure due to a decrease in the evaporation amount on the evaporation surface 6 or the like, the urging force of the pressure adjusting spring 70 overcomes the diaphragm. The stem 69 is pushed down by 68. As a result, the movable piece 77 rotates counterclockwise, and the valve body 84 is urged by the spring 86 in a direction away from the valve seat 83 via the valve rod 85, so that the liquid liquefied gas into the pressure chamber 62 is discharged. be introduced. In this way, by the operation of the vaporization pressure adjustment valve 60, the pressure in the pressure chamber 62 is held at the set pressure according to the consumption amount of the liquefied gas or the evaporation state in the evaporation unit 1, and the liquid phase liquefaction according to the consumption amount The gas can be vaporized to supply a liquefied gas having a stable pressure and amount to a gas consuming device or the like.

On the other hand, in the evaporation unit 1, the temperature detected by the temperature sensor 5 provided between the evaporation surface 6 and the electric heater 4 is input to the temperature controller 50. The temperature controller 50 maintains the temperature detected by the temperature sensor 5, which is the temperature of the heat transfer block 2 at the part where the temperature sensor 5 is inserted, in a preset temperature range (for example, 35 ° C. to 46 ° C.). The energization of the electric heater 4 is controlled. The energization control of the electric heater 4 can be, for example, a control that turns off the energization when the detected temperature reaches the upper limit T _H ° C of the set temperature range and turns on when the detected temperature falls to the lower limit T _L. In addition, temperature control that varies the voltage supplied to the electric heater 4 can be applied.

  Here, the effect of the temperature control operation of the present embodiment will be described with reference to FIG. In the figure, the horizontal axis indicates the time axis, and the vertical axis indicates the temperature axis. The figure shows the temperature change of the representative part of the heat transfer block 2, the solid line is the temperature control characteristic of this embodiment, the dotted line is the temperature control characteristic of the comparative example, and the temperature sensor 5 is more heat transfer than the electric heater 4. This is an example in which the block 2 is positioned below the block 2.

  As can be seen from FIG. 3, as in this embodiment, the temperature sensor 5 is positioned between the electric heater 4 and the evaporation surface 6 so that the temperature of the heat transfer block 2 at that portion falls within the set range. According to the temperature control for controlling the energization of the heater 4, the temperature change of the evaporation surface 6 can be reduced. Thereby, according to a present Example, the stable evaporation capability with few changes of the overall heat transfer coefficient in the evaporation part 1 can be hold | maintained. Further, the closing pressure of the vaporization pressure control valve 60 for supplying the liquid phase liquefied gas to the evaporation surface 6 is stabilized. In particular, the temperature change of the evaporation surface 6 can be reduced, and the temperature change width of the heat transfer block 2 can also be reduced. In other words, compared to the comparative example, the undershoot (the part enclosed by an ellipse in the figure) in which the temperature fluctuates downward can be reduced by temperature control, so that the liquid phase liquefied gas can be effectively and stably vaporized. it can. Moreover, in order to prevent the liquid phase liquefied gas from flowing out from the evaporator to the gas consuming device, etc., a liquid outflow prevention device is generally provided, but since the temperature control undershoot can be reduced, the liquid outflow prevention device A margin can be given to the operating temperature. That is, since the set temperature range of the temperature controller can be set to be low as a whole, the lifetime of the seal member and the electrical parts of the evaporator can be extended.

  Further, according to the present embodiment, the electric heaters 4 formed in one or a plurality of rod shapes perpendicularly to the heat exchange flow path 3 are inserted between the heat exchange flow paths 3 in a distributed manner. The temperature distribution of the heat block 2 can be made uniform, and the liquid phase liquefied gas can be evaporated and heated efficiently and stably.

  As described above, according to the liquefied gas evaporator of the present invention, the liquid liquefied gas can be effectively and stably vaporized. In the above embodiment, the heat transfer block 2 is formed of an aluminum alloy casting. However, the present invention is not limited to this, and a heat transfer member having excellent heat conductivity can be used. Further, when the plurality of heat exchange channels 3 are drilled in parallel from the liquefied gas introduction side to the discharge side, the respective channels can be arranged in a lattice pattern.

DESCRIPTION OF SYMBOLS 1 Evaporation part 2 Heat transfer block 3 Heat exchange flow path 4 Electric heater 5 Temperature sensor 6 Evaporation surface 8 Vaporized gas chamber 10 Outlet nozzle 50 Temperature controller 60 Vaporization pressure adjustment valve

Claims (3)

A heat transfer block in which a heat exchange flow path for liquefied gas is vertically drilled, a heat source inserted in the heat transfer block, a temperature sensor inserted in the heat transfer block, and a detected temperature of the temperature sensor And a temperature controller that controls the heat generation of the heat source, and an evaporation surface is formed on the surface of the heat transfer block in which an upper end of the heat exchange channel is opened, and a pressure provided to cover the evaporation surface A liquid phase liquefied gas is introduced into the chamber , and the vaporized liquefied gas is discharged from the opening at the lower end of the heat exchange channel;
The temperature sensor is a liquefied gas evaporator located between the heat source and the evaporation surface.   The liquefied gas evaporator according to claim 1, wherein the temperature controller controls the heat generation of the heat source so that the temperature detected by the temperature sensor falls within a set temperature range.   The liquefied gas evaporator according to claim 1, wherein the heat source is an electric heater, and the temperature controller controls heat generation of the electric heater by controlling energization of the electric heater.

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