JP2009052596A - Vaporizing method for liquefied gas, vaporizing device and liquefied gas supply device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vaporizing method for liquefied gas, a vaporizing device and a liquefied gas supply device, stably supplying liquefied gas in a gas phase to gas consumption equipment, and having high energy efficiency, and high function. <P>SOLUTION: This liquefied gas supply device includes: a heat medium supply part 6 for controlling the temperature of a heat medium and circulating and supplying the heat medium; a space part 1c disposed in contact with the bottom 1a and the outer peripheral part 1b of a filling container 1; a heating part 5 disposed in a space close to the bottom 1a of the space part 1c or disposed in the interior of a heat medium inlet pipe 4 provided in the space; and a control part for controlling the above parts, wherein both in the state of supplying liquefied gas and in the state of stopping the supply, the control part controls the control temperature and the supply flow of the heat medium in the heat medium supply part 6 and the heating value added to the heating part 5, and adjusts the gas phase pressure in the filling container 1 to be higher than the saturated vapor pressure of liquefied gas at the controlled temperature of the heat medium. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for vaporizing a liquefied gas, a vaporizer, and a liquefied gas supply device using the same, and, for example, a liquefied gas that requires vaporization during use or air feeding, such as a special material gas for semiconductors. The present invention relates to a method for vaporizing a liquefied gas used for gas vaporization treatment, a vaporizer, and a liquefied gas supply device for supplying a liquefied gas treated using the same.

Special material gases and various process gases used in semiconductor manufacturing processes and various processes have vapor pressures typified by BCL ₃ , SiH ₂ CL ₂ , HF, CLF ₃ , WF _6, etc. at or below atmospheric pressure. Very low liquefied gases are often used. Like other material gases, such low vapor pressure liquefied gas is usually delivered to and delivered to semiconductor manufacturing plants and various processes that are filled in a high pressure gas container in a liquid state and consume the liquefied gas. After being transferred and filled from the high-pressure container or from the high-pressure container to another container provided in the factory or process, it is vaporized and supplied to the gas consuming equipment (hereinafter this container is referred to as “filling container” or simply “container”). "). At this time, in the semiconductor manufacturing process apparatus and various process apparatuses (hereinafter referred to as “process apparatus”) which are liquefied gas consumption facilities, these liquefied gases are received in a gaseous state, not in a liquid state, and used in a gaseous state. Therefore, the liquefied gas filled in the container is stored in a gas supply facility called a cylinder cabinet, and is vaporized in the container to be in a gaseous state and sent out to a pipe connected to the process apparatus.

  In general, when the liquefied gas is vaporized and supplied, when the gas in the gas phase part is released to the outside of the container, the pressure in the gas phase part moves in a decreasing direction. Immediately, the liquefied gas is vaporized from the liquid phase part so that the pressure drop in the gas phase part is suppressed. However, since the heat energy required for this vaporization is made in a form that consumes the energy of the liquid phase part, the liquid phase temperature gradually decreases, and the vapor pressure of the gas phase part also decreases as the liquid phase temperature decreases. As a result, the supply pressure of the liquefied gas gradually decreases, and finally there arises a problem that the liquefied gas cannot be supplied at a desired flow rate. In other words, the amount of heat that naturally enters from the outside of the container contributes only after the temperature difference between the inside and outside of the container is caused by the temperature inside the container decreasing with respect to the outside temperature. To solve the problem of insufficient supply due to insufficient pressure, the technical problem that the amount of heat that naturally enters is insufficient is the background.

  In order to deal with such a problem, a liquefied gas supply facility 100 having a configuration as shown in FIGS. 12A and 12B is generally used. Specifically, FIG. 12A provides a space 102 around the periphery and bottom of the field-installed container 101, and FIG. 12B shows a space around the transport-type container 103. In this system, spaces 104 are provided, and a heat medium having a temperature higher than room temperature is supplied from each heat medium supply unit 105 to each space and circulated constantly. This method has the effect of only increasing the internal energy of the liquefied gas in the liquid phase portion L by previously raising the temperature of the liquefied gas above room temperature. It does not change even if it falls gradually by depriving the vaporization heat from the phase part L. Here, the entry of heat from the heat medium circulating around the outer periphery of the containers 101 and 103 contributes to suppressing the decrease in the liquid phase temperature while vaporizing while consuming energy from the liquid phase portion L. As a result, the liquid phase temperature is lowered to some extent, and a temperature difference between the inside and outside of the container is generated. Therefore, as a low vapor pressure liquefied gas supply facility that originally has a low vapor pressure, the supply pressure drop is sooner or later in the case of simply increasing the temperature of the liquid phase portion L as shown in FIGS. 12 (A) and 12 (B). This will cause a problem of shortage of supply.

In addition, when such a heating method is applied to a low vapor pressure liquefied gas whose vapor pressure of the liquefied gas is at room temperature or lower than atmospheric pressure, the flow through the supply pipe is saturated at a temperature higher than the ambient temperature of the pipe. It becomes a vapor pressure, and this saturated vapor is reliquefied by being cooled by the supply pipe. The low vapor pressure liquefied gas used in the semiconductor process and the like is mostly corrosive gas as represented by HF and CLF ₃ and has strong corrosivity. This causes problems such as metal contamination of the process due to entrainment of corrosion products that must be avoided most in the semiconductor process, liquid sealing by reliquefied condensate in a narrow part such as a valve, and pressure fluctuation due to the crack phenomenon. To solve this problem, it is extremely difficult to manage because the temperature of all gas contact parts in the supply piping and gas consuming equipment must be kept higher than the heating temperature of the liquefied gas filling container. Since temperature control is required, realization becomes a heavy load. Thus, in the case of low vapor pressure liquefied gas, how to increase the supply amount while vaporizing and evaporating at a temperature lower than the environmental temperature where the piping and gas consuming equipment are located to avoid the above-mentioned reliquefaction problem. It always has a difficult problem of having to clear the problem of whether it can be supplied stably.

  On the other hand, for example, a liquefied gas supply apparatus having a configuration as shown in FIG. 13 has been proposed with a focus on heating the bottom of the transfer container to prevent a decrease in supply pressure. Specifically, an installation base 211 on which the gas container 210 is placed, a heat medium ejection nozzle 212 that ejects a heat medium toward the bottom surface of the gas container 210, and a heat medium whose temperature is adjusted to the heat medium ejection nozzle 212. A heating medium supply line 213 to be supplied; and a container cover 214 formed of a half-cylinder-shaped pair of cylinders provided on the upper surface of the installation base 211 so as to surround the gas container 210. The heat medium ejected at a high speed toward the side of the gas container 210 is heated or cooled on the bottom surface of the gas container 210 and then discharged to the space 225 on the inner periphery of the container cover 214 through the outer peripheral side of the slit 219c (see, for example, Patent Document 1). ).

As described above, an attempt to suppress the temperature drop of the liquid phase part by transferring heat from the outside of the container to the liquid phase part of the liquefied gas inside the container through the wall surface of the container is a vapor having a relatively high vapor pressure. Is effective for liquefied gas having a pressure such as HCL, HBr, NH ₃ , CL _2, etc., while the vapor pressure of CLF ₃ , HF, WF _6, etc. targeted by the present invention is near atmospheric pressure. Low vapor pressure liquefied gas, which is lower than atmospheric pressure and has a very small allowable pressure drop, cannot be adequately handled due to poor heat conduction responsiveness, and when the liquefied gas consumption flow rate is large, There were problems that pressure was unstable and long-term continuous supply was not possible.

JP 2003-227597 A

  The technical problems that must be solved in order to stably supply the low vapor pressure liquefied gas as described above are summarized as follows.

(I) The problem that a supply pressure drop due to a delay in heat supply from the outside of the container causes a malfunction of the mass flow control function of the process. For low-vapor pressure liquefied gas, as in the case of other liquefied gas and compressed gas, the container The energy for sending the liquefied gas vaporized in the inside to the process apparatus is only pressure energy called vapor pressure of the liquefied gas. Therefore, when the temperature of the liquefied gas in the container fluctuates, the vapor pressure of the liquefied gas also fluctuates, and the supply pressure of the liquefied gas also fluctuates. Pressure can be stabilized with a pressure regulator (pressure reducing valve) if it is a general high-pressure gas, but the vapor pressure itself is very low with a low vapor pressure liquefied gas. I can't expect it. In the conventional method, the heat of vaporization that is instantly taken away from the liquid phase during vaporization is not quickly replenished from the outside of the container, so that the liquidus temperature is lowered, and the resulting change in vapor pressure is the same as the supply pressure of the liquid gas. As a result, the mass flow rate in the process apparatus also fluctuates due to fluctuations in the supply pressure to the process, leading to defects in the processing process.

  (Ii) As shown in FIGS. 12A and 12B, an attempt to increase the vapor pressure by simply increasing the temperature level of the liquefied gas, which is a conventional measure, and to suppress fluctuations in the supply pressure of the liquefied gas, As described above, another problem arises that the liquefied gas is reliquefied in the middle of the supply pipe or in the gas consuming equipment. Therefore, in the supply of the low vapor pressure liquefied gas, even if the liquefied gas is vaporized at a temperature lower than room temperature, the low vapor pressure is further lowered and the allowable range of decrease in the liquid phase temperature is narrowed. Therefore, there is a demand for a vaporizing and supplying apparatus having a heat replenishment capacity that exceeds the above. Here is the essence of the difficulty of supplying the low vapor pressure liquefied gas not found in other gases.

(Iii) Effect of fluctuations in ambient temperature of the filled vaporization vessel Also, the low vapor pressure liquefied gas originally has a low vapor pressure of around atmospheric pressure or lower, so the ambient environment that was not a major problem with conventional liquefied gas supply devices The pressure fluctuation of the vaporized liquefied gas caused by the temperature fluctuation cannot be ignored, and there is a problem that this pressure fluctuation becomes a fluctuation of the mass flow rate of the process apparatus. Conventionally, as shown in FIGS. 12 (A) and (B), a method of controlling the temperature around the liquefied gas filling container at a temperature higher than room temperature is sometimes used. As described above, it is not a good solution because reliquefaction occurs at the gas contacting part inside the apparatus.

  (Iv) Since the vaporization of the liquefied gas in the container occurs in the surface layer of the liquid phase in contact with the gas phase, the temperature of this portion is first cooled, and the temperature of the entire liquid phase is not instantaneously cooled on average. Therefore, since the temperature of most of the liquid phase does not decrease immediately, the difference between the internal and external temperatures of the container does not occur immediately. If there is no temperature gradient, no heat enters from the outside of the container, so that evaporation continues while consuming the energy of the vigorous liquefied gas itself. The temperature imbalance between the surface part of the liquid phase where the vaporization phenomenon has occurred and the liquid phase part of the other part is due to the effect of heat being transferred in the liquid phase and the increase in the specific gravity of the liquid phase as the temperature drops. The temperature of the entire liquid phase gradually decreases due to the movement of mass (material), that is, convection motion. As a result, a temperature gradient inside and outside the container is gradually generated, and heat is first supplied from the outside of the container. Usually, the heat and mass transfer between the liquid phase at the gas-liquid interface and the liquid phase at other portions is slow, so that the vapor pressure governed by the liquid-phase temperature at the gas-liquid interface gradually decreases. As a method of preventing the pressure drop in the gas phase due to the delay in heat supply from the outside, the pressure change in the gas phase is monitored, and when the pressure drops, the heat medium is sprayed on the container surface in conjunction with it. In addition, a heating control method has been devised that forcibly generates heat from the outside of the container to the inside of the container to prevent a decrease in the pressure in the gas phase (for example, Patent Document 1 [Claims 6 to 8] and related descriptions) reference). However, in the case of a liquefied gas whose vapor pressure targeted by the present invention is atmospheric pressure or lower than that, the allowable pressure fluctuation range is even smaller than that of other liquefied gases. It was difficult to fit in the width.

  (V) Further, in the method of monitoring the pressure change in the gas phase portion, the fact that the gas phase pressure is surely decreased is sensed, and at that time, the temperature of the outer peripheral portion of the filling container is temporarily increased to increase the pressure from the outside. However, when the consumption of the liquefied gas is stopped, the heating control is performed in conjunction with the pressure in the gas phase. When the temperature of the liquid phase surface layer near the interface is recovered, heat supply from the outside is stopped even if the other liquefied gas liquid phase temperatures are not sufficiently recovered. Once this state is reached, the liquid phase temperature of the upper part of the liquid phase becomes higher and the liquid specific gravity of that part becomes lighter than the liquid specific gravity of the other liquid phase parts. The liquid is stabilized in a state where it has not recovered, and convection that should contribute to the homogenization of heat does not occur, and the average temperature of the entire liquid does not recover and the next gas consumption starts. In the low vapor pressure liquefied gas vaporization supply device, the effect of pressure fluctuation at the start of supply due to the decrease in the energy of the liquefied gas every time gas consumption stops can not be ignored, so some improvement is required. It was.

  The object of the present invention is to respond to such problems and provide a vaporization apparatus with high energy efficiency and excellent functionality that can be stably supplied to gas consuming equipment in a gas phase and a liquefied gas supply apparatus using the same. There is to do. In particular, an object of the present invention is to provide a liquefied gas vaporization method, a vaporizer, and a liquefied gas supply apparatus using the same, which can be used for heat treatment of a liquefied gas such as a special material gas for semiconductors having a low vapor pressure and various process gases.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by a liquefied gas vaporization method, a vaporizer, and a liquefied gas supply apparatus using the same as described below. The invention has been completed.

The present invention is a method for vaporizing a liquefied gas, wherein a liquefied gas in a gas phase portion is sent to a consuming facility from a liquefied gas filling container stored in a state where the liquid phase and the gas phase coexist,
A state in which the temperature-controlled heat medium is circulated in a space disposed so as to be in contact with the bottom and the outer periphery of the filling container, and the liquefied gas is supplied and stopped. In any case, by controlling the amount of heat applied to the space close to the bottom of the space or the heating section provided in the heat medium introduction pipe provided in the space, the air inside the filling container is controlled. The phase pressure is adjusted to be higher than the saturated vapor pressure of the liquefied gas at the control temperature of the heat medium.

The present invention is a liquefied gas vaporizer that feeds the liquefied gas in the gas phase portion from the liquefied gas filling container stored in a state where the liquid phase and the gas phase coexist,
A space portion disposed so as to contact the bottom and the outer peripheral portion of the filling container, a heat medium supply portion for controlling the temperature of the heat medium and circulatingly supplying the space to the space portion, and a space close to the bottom portion of the space portion Or having a heating unit disposed inside the heat medium introduction pipe provided in the space, and a control unit for controlling these,
In both the state where the liquefied gas is supplied and the state where the supply of air is stopped, the control unit determines the control temperature and supply flow rate of the heat medium in the heat medium supply unit, and the amount of heat applied to the heating unit. And controlling the gas phase pressure inside the filling container to be higher than the saturated vapor pressure of the liquefied gas at the control temperature of the heat medium.

In order to stably supply a liquefied gas such as a liquefied gas by the vaporizing means, it is important to maintain the temperature of the liquid phase by the heat of vaporization after the start of supply as well as the temperature conditions at the start of the supply. At this time, it is not the temperature of the entire liquid phase but the temperature of the superficial part of the liquid phase at the gas-liquid interface that directly controls the vapor pressure of the gas phase, that is, the vapor pressure of the liquefied gas. The key point is to maintain the temperature of the surface portion of the liquid phase in order to send the liquid stably. However, in the conventional method, it was difficult to maintain the temperature of the liquid surface layer portion where the vapor-liquid interface where the heat of vaporization is locally and selectively removed is very thin. In order to maintain the liquid phase temperature of the surface layer, heat corresponding to the heat of vaporization can be supplied from the outside of the container with good responsiveness, and the amount of heat supplied along the wall of the container must be quickly conveyed to the liquid phase surface. I must. For this purpose, relying solely on heat conduction in a stationary state in the liquid phase is not in time. It depends on how quickly the heat transmitted through the wall surface is transferred to the liquid surface of the gas-liquid interface. The present invention
(I) By having the space part in which the heat medium is circulated so as to be in contact with the outer peripheral part and the bottom part of the container, the influence of the ambient temperature of the container can be eliminated.
(Ii) By adopting a structure in which heat energy can be intensively applied to the bottom of the container, heat is selectively replenished from the bottom of the container to cause an upward flow in the liquid phase, and the outer peripheral side surface of the container By generating a temperature difference with the liquid phase part of the liquefied gas, positive convection is formed, and the replenished heat is quickly sent to the gas-liquid interface part where the vaporization phenomenon occurs, Prevents the liquid phase temperature from decreasing and ensures a stable gas phase pressure.
(Iii) Even when the consumption of the liquefied gas is stopped, convection of the liquid phase part is always generated, and the pressure of the gas phase part is the saturated vapor pressure of the liquefied gas at the temperature of the heat medium circulating in the outer periphery of the container Maintain a higher pressure. Specifically, a heater for additionally applying heat to the heat medium sprayed on the bottom surface of the container is provided, and the amount of heat added in conjunction with the pressure in the gas phase is controlled.
(Iv) Further, as will be described later, a film heat transfer coefficient on the outer wall surface of the container is injected by injecting a liquid phase heat medium from a nozzle having an injection port perpendicular to the center of the bottom surface of the container. And improving the overall heat transfer coefficient for transferring heat from the heat medium to the liquid phase in the container by making the wall thickness of the container wall irradiated with the jet of heat medium thinner than other parts. Thus, the thermal conductivity transmitted from the heat medium to the wall surface of the container can be improved.
It is characterized by having the function.

  In other words, in response to pressure fluctuations associated with environmental temperature fluctuations, which is one of the problems described above, the present invention provides a heat medium that is always regenerated by a constant temperature heat medium supply unit as an outer periphery of a container filled with liquefied gas By eliminating the structure that always circulates to the bottom and bottom, the problem is solved. Further, in response to pressure fluctuation due to heat balance imbalance, which is another problem, the present invention quickly compensates for the heat corresponding to the vaporization heat deprived from the liquid phase, particularly its surface layer, when the liquefied gas is vaporized. In addition, by injecting a heat medium from a nozzle having an injection port perpendicular to the center of the bottom of the filling container, an upward flow is generated in the center of the liquid phase to form a convection in the liquid phase. This is achieved by ensuring the uniformity of the phase temperature.

The present invention is a method for vaporizing a liquefied gas in which a liquefied gas in a gas phase portion is sent to the consuming equipment from a liquefied gas filling container stored in a state where the liquid phase and the gas phase coexist,
A temperature-controlled heat medium is circulated to two independent spaces Sa and Sb arranged so as to be in contact with each of the bottom and the outer periphery of the filling container,
In both the state of supplying the liquefied gas and the state of stopping the supply of air, a heat medium supplied to the space portion Sa in contact with the bottom portion is installed in the space portion Sa or in the space portion Sa. By controlling the amount of heat applied to the heating unit disposed inside the heat medium introduction pipe, the gas phase pressure inside the filling container is higher than the saturated vapor pressure of the liquefied gas at the control temperature of the heat medium. It adjusts so that it may become high.

The present invention is a liquefied gas vaporizer that feeds the liquefied gas in the vapor phase from the liquefied gas filling container accommodated in a state where the liquid phase and the gas phase coexist,
A heat medium supply unit that circulates and supplies the heat medium with temperature control;
A space Sa disposed so as to be in contact with the bottom of the filling container;
A space portion Sb that is disposed in contact with the outer peripheral portion of the filling container and is independent of the space portion Sa;
After the heat medium supplied from the heat medium supply part is introduced into the space part Sb from the introduction part provided in the space part Sb, the flow is supplied from the outlet provided in the space part Sb. Road B,
A flow path A in which the heat medium delivered from the flow path B is introduced into the space portion Sa from a heat medium introduction pipe disposed in the space portion Sa;
A heating unit disposed in the heat medium introduction pipe or in the space Sa,
In any of the state where the liquefied gas is supplied and the state where the supply of air is stopped, the heat medium supplied from the flow path B is additionally heated by the heating unit.

As described above, the heat medium according to the present invention not only simply controls the temperature of the space around the outer periphery of the container and keeps the temperature of the liquid phase inside the container constant, but also the ambient temperature of the container, piping, etc. A proper temperature difference between the liquid phase temperature and the liquid phase part, creating a temperature difference between the central part and the peripheral part of the liquid phase part to form a convection in the liquid phase and It has an excellent function of ensuring temperature uniformity. Here, the addition of heat from the bottom of the container plays an important role in controlling the temperature of the central part of the liquid phase part, and the control of the temperature in the peripheral part of the liquid phase part is performed in the outer peripheral part of the container. The presence of the heat medium plays an important role. That is, in the space part into which the heat medium is introduced, the space part Sa in contact with the bottom part of the container and the space part Sb in contact with the outer peripheral part of the container have different roles, and thus can form independent spaces. In addition to this, several excellent functions and effects can be obtained as follows.
(I) By using independent spaces, independent temperature control of each space portion is facilitated, and control accuracy can be increased. Therefore, it is effective for the purpose of accurately controlling a small temperature difference between the bottom surface and the side surface of the container as in the present invention.
(Ii) As in this configuration, by introducing the heat medium whose temperature has been previously controlled into the space part Sb and introducing the supplied heat medium into the space part Sa for heating, a temperature drop occurs during the supply. The heated heat medium can be heated and irradiated to the bottom of the container as a heat medium having a constant temperature higher than the control temperature.

The present invention is the above-described method for vaporizing a liquefied gas, wherein the heating medium heated by the heating unit provided inside the heating medium introduction pipe and supplied from the heating medium introduction pipe is used as the filling container. By selectively irradiating the center of the bottom of the liquid, the heat input to the liquefied gas at the center of the filling container is raised from the other bottom, and the liquid phase rises at the center of the liquid phase. It is characterized by generating convection descending at the outer periphery of the phase.
As described above, the formation of convection inside the liquid phase has an important function to ensure a stable gas phase pressure by preventing the liquid phase temperature of the liquid phase layer from decreasing due to the feeding of the liquefied gas. Plays. The present invention has found that in order to more efficiently form such convection, it is preferable to irradiate the heated heat medium in a concentrated manner, particularly at the center of the bottom surface of the container. In other words, by adopting a structure that can intensively add heat energy to the center of the bottom of the container, the center is selectively replenished with heat, and an upward flow is actively caused in the center of the liquid phase. By setting the heat medium flow path on the outer surface of the container so as not to supply additional heat from the outer peripheral side of the container, positive convection is formed in the liquid phase of the liquefied gas, and it is replenished along the container wall surface. Thus, a stable gas phase pressure can be ensured by promptly feeding the heat to the gas-liquid interface part where the vaporization phenomenon has occurred and preventing the liquid phase temperature of the liquid phase surface part from decreasing. As specific means, as described later, by a method of injecting heat by injecting a heat medium perpendicularly from the injection nozzle to the bottom surface of the container, or by making the thickness of the central portion of the bottom surface of the container thinner than the other parts It can be realized.

  The present invention is the liquefied gas vaporizer, wherein the heat medium is perpendicular to the wall of the space connected to the heat medium introduction pipe and in contact with the center of the bottom surface in the space contacting the bottom of the filling container. A nozzle to be sprayed is disposed, and a heating unit is disposed inside the heat medium introduction pipe.

  As described above, in order to more efficiently form convection in the liquid phase, it is preferable to irradiate the heated heat medium in a concentrated manner, particularly at the center of the bottom surface of the container. As a specific means of the present invention, heat is injected by injecting a heat medium perpendicularly from the injection nozzle to the bottom surface of the container, and by improving the film heat transfer coefficient on the outer wall surface of the container, It is possible to more efficiently form convection inside the liquid phase. Furthermore, by arranging the heating part inside the heat medium introduction pipe in which the nozzle is arranged and the heat medium is introduced, more accurate controlled heat input can be performed, and the stable liquid phase inside The formation of convection can be ensured.

  The present invention is the liquefied gas vaporizer, wherein the pressure detector is connected to the gas phase part of the filling container, and the amount of heat applied to the heating part and / or the measured value as an index and / or It has a function of controlling the flow rate of the heat medium.

  As described above, in order to vaporize liquefied gas having a low vapor pressure in a stable manner, temperature control at the gas-liquid interface is important. The present invention secures stable temperature conditions around the container and stable supply of heat, and heats the bottom of the container intensively to form convection in the liquid phase to provide stable supply of heat to the gas-liquid interface. By ensuring the stable vaporization conditions, the pressure in the gas phase in the container (vapor pressure, hereinafter referred to as “gas phase pressure”) is constantly monitored, and the monitored gas phase pressure decreases. Immediate warming operation enables quick response to minute changes. That is, the heating medium (immersion heater) incorporated in the heat medium introduction flow path is operated on demand according to the drop in the gas phase pressure, and the heat medium flowing around the container by the heat applied from the heater. By temporarily raising the temperature (circulated and supplied from the heat medium supply unit) above the constant temperature, the problem of pressure fluctuation due to heat balance imbalance is more effectively solved.

  The present invention is the above liquefied gas vaporizer, characterized in that the thickness of the central portion of the bottom surface of the filling container is thinner than the other portions.

  As the filling container for the liquefied gas, a thick and strong metal container is used in order to prevent breakage during pressure resistance or transportation. On the other hand, from the viewpoint of stabilizing the temperature of the liquid phase part or the gas phase part in the container, the container is preferably as thin as possible. In the present invention, as described above, the central portion of the bottom surface of the filling container is an important part for achieving a uniform liquid phase temperature inside the filling container, and is relatively thin without impairing the robustness of the filling container. Based on the knowledge that it is a part that can be made, the thickness of the central portion of the bottom surface of the container is made thinner than the other parts to ensure a high heat transfer function. As a result, the heat medium is sprayed onto the central portion of the bottom surface of the container, and further, an upward flow is generated in the central portion of the liquid phase to form convection in the liquid phase to ensure the uniformity of the liquid phase temperature. It became possible. In particular, the liquid phase heat medium from a nozzle having an injection port perpendicular to the center of the bottom surface of the container is injected, and the wall thickness of the container wall to which the jet of the heat medium is irradiated is thinner than other parts. In such a case, the former aims to improve the heat transfer coefficient of the film on the outer wall surface of the container, and the latter aims to improve the overall heat transfer coefficient transferred from the heat medium to the liquid phase in the container. The heat conductivity transmitted from the heat medium to the wall surface of the container can be improved.

The present invention is a liquefied gas supply device for supplying a liquefied gas to a gas consuming facility which is supplied with a pipe from a filling container filled with liquefied gas and separated from the container,
Using the vaporization apparatus according to any one of claims 1 to 4, vaporization treatment of the liquefied gas filled in the filling container and / or reliquefaction after being installed in the vicinity of the gas consuming equipment and fed into the pipe. The liquefied gas stored in this way is vaporized.

  The liquefied gas supply device plays an important role in, for example, a semiconductor manufacturing process and the like, and even when the liquefied gas is supplied to a gas consuming facility that is supplied from a container and separated from the pipe, Supply is required. In particular, in the case of a liquefied gas with a low vapor pressure, problems such as the installation environment conditions of the vaporizer and a decrease in the supply amount due to the heat of vaporization after the start of air supply cannot be adequately addressed by conventional liquefied gas supply devices. It was. In order to solve such problems, the present invention uses the above vaporizer to stabilize the gas-liquid interface temperature of the liquefied gas in the filling container and to stabilize the gas phase pressure, that is, the air supply pressure. Even in the case of liquefied gas with low vapor pressure, it is possible to provide a liquefied gas supply device capable of ensuring a stable air supply pressure to the process device and stably supplying a desired flow rate. It became. In addition, after the liquefied gas that has been vaporized and sent in the container is forcibly liquefied once on the process apparatus side, which is a gas consuming facility, the liquefied gas is again vaporized using the vaporizer according to the present invention to the process apparatus. By supplying air, it became possible to secure a stable air supply pressure.

  As described above, according to the present invention, liquefied gas such as low vapor pressure special material gas for semiconductors and various process gases can be stably supplied to the gas consuming equipment in a gas phase state and has high energy efficiency. It has become possible to provide a liquefied gas vaporization method, a vaporizer, and a liquefied gas supply apparatus using the vaporized gas, which are functionally excellent.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. A space that is disposed so as to be in contact with the bottom and the outer periphery of the filling container and to which a heat medium is supplied, a heat medium supply unit that controls the temperature of the heat medium and circulates it into the space, and is close to the bottom of the space And a heating unit disposed inside the heating medium introduction pipe provided in the space and a control unit for controlling them, and in the control unit, control of the heating medium in the heating medium supply unit A liquefied gas vaporizer that controls the temperature, supply flow rate, and amount of heat applied to the heating section, and adjusts the gas phase pressure inside the filling container to be higher than the saturated vapor pressure of the liquefied gas at the control temperature of the heat medium. Is the basis. Here, a case where a low vapor pressure liquefied gas typified by HF, CLF ₃ , BCL ₃ , SiH ₂ CL ₂ , WF ₆ or the like is treated as the liquefied gas will be described.

<Example of basic configuration of vaporizer for liquefied gas according to the present invention>
FIG. 1 is a schematic diagram showing a basic configuration example of a liquefied gas vaporizer (hereinafter referred to as “the present vaporizer”) according to the present invention. The vaporizer mainly includes a filling container 1 filled with a liquefied gas, a jacket 2 that forms a space 1c to which a heat medium is supplied so as to be in contact with the bottom 1a and the outer periphery 1b, and a bottom center M of the bottom 1a. A nozzle 3 for injecting a heat medium in the vicinity, a heat medium introduction pipe 4 for supplying the heat medium to the nozzle 3, an immersion heater 5 (corresponding to a heating part) for heating the supplied heat medium, and temperature adjustment It is comprised from the heat medium supply part 6 which supplies a heat medium. A pressure sensor (corresponding to a pressure detection unit) 7 is disposed on the top of the filling container 1 and detects the pressure of the gas phase part G of the liquefied gas filled therein. The liquefied gas is supplied from the filling port 1d to the filling container 1 in a liquid state, vaporized, and supplied from the outlet port 1e in a gaseous state. These are comprehensively controlled by a control unit (not shown).

  At this time, by having the space 1c through which the heat medium can flow so as to be in contact with the outer periphery and the bottom of the cooling jacket 2, the heat is supplied from the periphery of the filling container 1, and the vicinity of the bottom center portion M of the filling container 1 By injecting the heat medium in a direction perpendicular to the liquid phase, an upward flow is generated in the central portion of the liquid phase portion L to form convection in the liquid phase, thereby ensuring the uniformity of the liquid phase temperature. . As a result, the liquefied gas can be uniformly vaporized from the liquid phase portion L inside the container, and a stable liquefied gas can be supplied. In addition, by incorporating the immersion heater 5 in the heat medium supply unit and heating the supplied heat medium, the heat of vaporization deprived from the liquefied gas in the liquid phase part L according to the supply amount of the liquefied gas, that is, the vaporization amount, can be quickly achieved. Therefore, the liquefied gas can be supplied at a more stable pressure.

  As illustrated in FIG. 1, the filling container 1 is transported in a state filled with liquefied gas and replenished by replacing the entire container, except when a stationary transfer filling container capable of replenishing liquefied gas from the filling port 1 d is used. It is possible to use a transport container. Here, it is preferable that the thickness of the bottom center portion M of the filling container 1 is thinner than other portions. Ensuring a high heat transfer function, transferring the heat from the heat medium injected to the relevant part to the central part of the liquid phase part L in the interior, generating an upward flow in the liquid phase and convection in the liquid phase This makes it possible to ensure the uniformity of the liquidus temperature. Specifically, as a result of the demonstration, the thickness of the circular portion corresponding to about 1/2 of the area of the bottom surface of the filling container 1 (circular region having a diameter of 1 / √2), the donut-shaped bottom portion surrounding it It turned out that it is preferable to make it the structure thinner than the thickness of 1a and the outer peripheral part 1b of the filling container 1. FIG.

  The space 1c on the bottom 1a side of the filling container 1 is provided with a nozzle 3 and a heat medium introduction pipe 4 for increasing the speed at which the heat medium is ejected, and the heat medium supplied from the heat medium supply unit 6 is Then, a circulation flow path is formed that returns to the heat medium supply unit 6 through the supply port 4a, the heat medium introduction pipe 4, the nozzle 3, the space 1c, and the outlet 2a. A heat medium having warm heat is ejected from the nozzle 3 and transfers heat to the liquid phase liquefied gas inside the filling container 1, thereby preventing a decrease in the liquid phase temperature due to the heat of vaporization. At this time, the shape of the tip of the nozzle 3 is a flat circle having a size that is approximately ½ of the area of the bottom 1a of the filling container 1, and the narrow portion 3a is disposed between the nozzle 3 and the bottom 1a of the filling container 1 facing the nozzle 3. The constant temperature fluid sprayed in the vicinity of the center portion M of the bottom surface of the filling container 1 passes through the narrow portion 3a, so that the flow rate and pressure of the heat medium are higher than other portions of the space portion 1c. It is preferable.

Next, functions and functions unique to the present vaporizer that function by such a configuration will be described. That is, this vaporizer has the following actions and functions.
(A) By supplying the heat medium cyclically to the space 1 c inside the jacket 2 around the filling container 1, the influence of fluctuations in the external environment temperature of the filling container 1 is blocked and fluctuations in the supply pressure are prevented. .
(B) By spraying the heat medium at right angles to the bottom center part M of the filling container 1, the film heat transfer coefficient on the outer wall surface of the filling container 1 is improved, and a jet of the heat medium is further irradiated. By making the wall thickness of the container wall thinner than other parts, the overall heat transfer coefficient for transferring heat from the heat medium to the liquid phase inside the filling container 1 is improved, and the wall surface of the filling container 1 from the heat medium Increases the thermal conductivity transmitted to
(C) Not only makes the temperature of the liquid phase part inside the container constant, but also forms an appropriate temperature difference between the ambient temperature and liquid phase temperature of the container and piping, etc. By creating a temperature difference and forming convection in the liquid phase, temperature uniformity between the liquid phase surface layer part and other liquid phase parts is ensured. In the former, the control temperature of the heat medium in the space 1c inside the jacket 2 of the filling container 1, that is, the control temperature of the circulating heat medium contributes, and in the latter, the control temperature of the heat medium ejected from the nozzle 3, that is, the immersion heater 5 is. Since it contributes, the temperature of the liquid phase surface layer can be maintained by forming a non-equilibrium condition in which a temperature difference is provided between them.
(D) By adopting a structure in which heat energy can be intensively applied to the bottom center part M, heat is selectively replenished to the bottom center part M, and an upward flow is actively caused in the center part in the liquid phase. By setting the heat medium flow path on the outer surface of the container so as not to supply additional heat from the outer peripheral side surface of the filling container 1, positive convection is formed in the liquid phase of the liquefied gas, and the wall surface of the filling container 1 The heat replenished through the gas is promptly sent to the gas-liquid interface where the vaporization phenomenon has occurred, the vaporization heat of the liquefied gas and the balance of heat balance between the heat supply from the surroundings of the filling container 1 are suppressed, It is possible to prevent pressure fluctuations accompanying temperature changes on the liquid phase surface.
(E) Even when consumption of the liquefied gas is stopped, convection of the liquid phase portion is always generated, and the pressure of the gas phase portion is the saturated vapor pressure of the liquefied gas at the temperature of the heat medium circulating in the outer periphery of the vessel Higher pressure can be maintained. Specifically, a heater for additionally applying heat to the heat medium sprayed on the bottom surface of the container is provided, and the amount of heat added in conjunction with the pressure in the gas phase is controlled.

[Thermal control of heat medium]
In order to simultaneously secure the functions and functions as described in (a) to (d) above, the total amount of heat of the heat medium supplied from the heat medium supply unit 6 and the bottom center part M of the filling container 1 are injected at right angles. It is necessary to control the amount of heat of the heat medium to be generated. That is, not only the temperature and supply amount of the heat medium supplied from the heat medium supply unit 6 are controlled, but also the temperature of the heat medium ejected from the nozzle 3, specifically, the temperature and supply amount of the heat medium introduction pipe 4 are controlled. It is important to control.

(1) Temperature control of the heat medium supplied from the heat medium supply unit 6 In order to always provide heat to the filling container 1 in a circulating manner from the surroundings, and to maintain the uniformity of the liquid phase temperature of the liquefied gas, The temperature of the supplied heat medium is an important control target. Conventionally, the temperature of the heat medium supplied from the heat medium supply unit 6 to the filling container 1 is determined as follows according to the vapor pressure (supply pressure) of the liquefied gas sent from the present vaporizer. That is, as shown in FIG. 2, in the temperature-saturated vapor pressure curve specific to the liquefied gas, the liquidus temperature of the liquefied gas at which the saturated vapor pressure corresponding to the supply pressure of the liquefied gas (Pv value in FIG. 2) is obtained ( In the conventional method, the temperature of the heat medium is set to a value equal to (Tv value in FIG. 2). On the other hand, the present vaporizer is characterized in that it is set to a value Tn [= Tv−α] lower than the Tv value. Here, the α value is preferably set to about 3 to 6 ° C., for example.

(2) Temperature control of the heat medium introduction pipe 4 In the present vaporizer, the temperature Tn of the heat medium supplied from the heat medium supply unit 6 to the filling container 1 keeps the supply pressure of the liquefied gas at a predetermined value Pv. The temperature is controlled to a value that is lower than the required liquidus temperature Tv by the α value, and is sent out from the heat medium supply unit 6. On the other hand, the heating part (immersion heater) 5 that additionally gives heat to the heat medium sent in that way is interlocked and controlled so that the pressure of the gas phase part G of the filling container 1 becomes the Pv value. Unlike the conventional method, not only when the vaporization device sends gas to the gas consuming equipment and the heat of vaporization is taken away from the liquid phase, but also when the gas consuming equipment is not sending air, The immersion heater 5 continues to operate so as to additionally apply heat to the heat medium sprayed in the vicinity of the bottom center portion M of the filling container 1. The difference in operation of the immersion heater 5 between when the vaporizer is supplying air and when stopping the supply of air is that the immersion heater that additionally gives heat to the heat medium sprayed near the bottom center portion M. The only difference is the amount of heat from 5 and the operating frequency. Even when not supplying air, the immersion heater 5 continues to operate intermittently.

  For the generation of convection in the liquid phase of the liquefied gas inside the filled container 1, the addition of partial heat from the bottom center M corresponding to the temperature drop due to heat of vaporization at the gas-liquid interface is an important control target. . That is, by increasing the temperature received by the liquid phase portion L of the liquefied gas from the heat medium in the vicinity of the bottom surface central portion M, as shown in FIG. A convection that forms a downward flow Fb can be formed at the portion, and the temperature is controlled so that such a convection pattern is always obtained. As a result, the liquid phase portion L heated at the bottom portion 1a becomes warmer and lighter than the other liquid phase portions L, and therefore, an upward flow Fa is formed near the center, and the gas-liquid interface causing a rapid vaporization phenomenon. Vaporization power is changed by replacing the liquid phase portion L, which is sent to Lg, and the liquid phase temperature, which is lowered by the heat of vaporization staying at the gas-liquid interface Lg, with the warm liquid phase portion L which has rapidly risen to the periphery. It acts to prevent a drop and a drop in gas phase pressure. At the same time, the liquid phase portion L, which has been near the gas-liquid interface Lg and has lost heat of vaporization and has fallen in temperature, is quickly repelled to the outer periphery, and further to the bottom 1a direction along the inner wall of the filling container 1 The downward flow Fb is formed. The liquid phase portion L whose temperature has been sent back to the bottom portion 1a in this way is replenished with heat at the bottom portion 1a, thereby receiving heat from the heat medium H flowing around the filling container 1 efficiently as a whole. It contributes to suppressing the fall of the vapor pressure by the heat of vaporization. As a result, it is possible to realize a vaporized supply apparatus for liquefied gas with very little fluctuation in supply pressure.

  In the present vaporizer, a circulation system is formed in which the heat medium supplied from the heat medium supply unit 6 is returned to the heat medium supply unit 6 through the heat medium introduction pipe 4, the nozzle 3, and the space 1c. Accordingly, the temperature of the supplied heat medium is high in the heat medium introduction pipe 4, that is, the nozzle 3, and in the space 1 c, the temperature is lowered by the amount of warm heat taken away by the bottom 1 a of the filling container 1. As a result, the convection in the liquid phase can be formed as described above, but further, the convection can be immersed in the heat medium in the heat medium introduction pipe 4 which is the flow path of the heat medium leading to the nozzle 3. It is preferable to arrange a warm part (immersion heater) 5. As soon as the gas phase pressure drops, a warming operation is performed, so that even a minute change can be quickly dealt with. The immersion heater 5 operates only when the gas phase pressure in the filling container 1 falls below the supply pressure set value. When the submerged heater 5 is operated, the heat medium sent to the bottom 1a of the filled container 1 temporarily becomes higher than the temperature of the heat medium so far, and as a result, the amount of heat input to the liquefied gas increases. A decrease in the liquid phase temperature of the liquefied gas is suppressed, and consequently a decrease in the gas phase pressure is suppressed. When the gas phase pressure is restored to the original pressure, the operation of the immersion heater 5 is stopped. The immersion heater 5 is ON / OFF controlled or PID controlled by the temperature controller 9 so that the liquefied gas pressure signal 8 from the pressure sensor 7 that monitors the gas phase pressure of the liquefied gas becomes a preset value. It has become. That is, the immersion heater 5 does not always operate, but performs a control operation based on on-demand control in conjunction with the gas phase pressure drop.

  FIG. 4 is a comparative explanation of pressure behavior in the present vaporizer. FIG. 4B shows the pressure behavior when the temperature control of the heat medium linked to the gas phase pressure is not performed. That is, it is a pressure behavior in the case where control is performed so that the temperature of the filling container 1 is simply kept constant without being interlocked with fluctuations in the gas phase pressure. FIG. 4A shows that the temperature of the heat medium circulating in the space 1c provided on the outer periphery of the filling container 1 is controlled to the same temperature as the liquid phase temperature Tv that generates the supply pressure of the liquefied gas as the saturated vapor pressure. In addition, when the liquefied gas is fed, the heat of vaporization is deprived from the liquid phase portion L, and when the liquid phase temperature is lowered and the gas phase pressure is lowered, the pressure drop is suppressed in the circulating heat medium. Therefore, the operation pattern of the heating part and the pressure behavior of the liquefied gas at that time when additional heat input control is performed are shown. FIG. 4C shows the operation pattern of the heating part and the pressure behavior of the liquefied gas when the temperature control of the vaporizer is applied to the heat medium circulating in the space 1c provided on the outer periphery of the filling container 1. Show. That is, the supply path of the heat medium is set so that the supply pressure of the liquefied gas becomes a predetermined value while keeping the temperature of the heat medium sent from the heat medium supply unit 6 lower than the liquidus temperature Tv. The operation pattern of the heating part (immersion heater 5) and the pressure behavior of the liquefied gas at that time when the amount of heat is secondarily applied to the heat medium and controlled by the immersion heater 5 disposed therein are shown.

  (2-1) FIGS. 4A and 4B compare and explain the pressure behavior when the liquid phase temperature control is functioned and when it is not functioned. As shown in FIG. 4 (B), when the liquid phase temperature is not controlled, the supply pressure gradually decreases with the passage of time due to the heat taken away when the liquefied gas is vaporized. As shown in FIG. 4A, when the liquid phase temperature is controlled, there is some fluctuation, but the fluctuation is suppressed to a low value that does not cause a problem in the supply of liquefied gas. The reduction of the supply pressure which has become does not occur. Specifically, in the case of not controlling the liquid phase temperature, (Ba) When the liquefied gas is consumed, the supply pressure greatly decreases with time due to the decrease in the liquid phase temperature due to the heat of vaporization. (Bb) Even after the supply is stopped Since the recovery of the liquid phase temperature is very slow, the recovery of the gas phase pressure is also slow. On the other hand, when the liquid phase temperature is controlled, (Aa) the immersion heater 5 performs ON / OFF operation (or PID operation) in conjunction with the gas phase pressure, so there is almost no pressure fluctuation, and (Ab) supply is stopped. Since there is no pressure fluctuation factor, the immersion heater 5 does not operate. In the verification test, it was confirmed that the fluctuation of the supply pressure when the liquidus temperature was controlled remained in a very small range of 10 kPa or less.

  (2-2) FIGS. 4C and 4D compare and explain the pressure behavior when the on-demand heating system in the vaporizer and the conventional control method is adopted. As shown in FIG. 4D, in the conventional control method, after the supply of the liquefied gas is stopped, the temperature of the liquid phase portion L other than the liquid phase surface layer portion is stabilized in a lowered state. As shown in FIG. 4C, in the present vaporizer, since the heated state is maintained even after the supply of the liquefied gas is stopped, the liquid phase temperature that has been a problem in the prior art does not decrease. Specifically, as shown in FIG. 4D, in the conventional control method, in the liquefied gas supply state, ON / OFF control (or PID control) is performed in conjunction with the gas phase pressure. Although there is almost no fluctuation, the average temperature of the entire liquid phase portion L gradually decreases due to the difference between the heat of vaporization that is instantly taken away and the heat input that is slower than that, and in this state the liquefied gas When the air supply is stopped, only the temperature of the (Db) liquid phase surface layer portion is recovered, and most of the other liquid phase temperatures are stabilized without being recovered. On the other hand, in the present vaporizer, as shown in FIG. 4C, in the liquefied gas supply state, the immersion heater 5 performs ON / OFF operation (or PID operation) in conjunction with the (Ca) gas phase pressure. Therefore, there is almost no pressure fluctuation and no decrease in the liquid phase temperature, and after the liquefied gas supply is stopped, (Cb) the heat of vaporization is not deprived, but the container outer peripheral portion 1b is higher than the set temperature of the immersion heater 5. Because of the non-equilibrium condition where the temperature of the side space 1c (the control temperature of the circulating heat medium) is low, the immersion heater 5 continues the ON / OFF operation (or PID operation), and (Da) the liquidus temperature Keep it almost constant. In the verification test, it was confirmed that the fluctuation of the supply pressure of the vaporizer stayed within a very small range of 10 kPa or less even when the supply of the liquefied gas was once stopped and then returned to the supply state.

Moreover, in this vaporization apparatus, in order to improve the responsiveness in this on-demand control, the following configurations function effectively in relation to each other.
(I) The heat medium additionally receiving heat by the on-demand heating system is configured to be jetted at a right angle close to the bottom 1a of the filling container 1.
(Ii) A nozzle 3 is provided at the end of the heat medium introduction pipe 4 in order to increase the speed at which the heat medium is ejected to the bottom 1a. (Iii) The bottom surface of the doughnut surrounding the thickness of the bottom 1a of the filling container 1 is provided. And it is set as the structure made thinner than the thickness of the side wall surface of a storage container.
(Iv) The tip shape of the nozzle 3 is a flat circle, and the narrow portion 3a is provided between the nozzle 3 and the bottom portion 1a facing it.

  The convection formation conditions in the inside of the filling container 1 are set by using the filling container 1 filled with a predetermined liquefied gas in advance, the environmental temperature, the temperature / flow rate of the heat medium, and the supply pressure of the vaporized liquefied gas ( It can be determined by simulating the conditions of convection generation using temperature and flow rate as an index. The existence of convection can also be verified by assuming it at the time of the simulation. However, a method of actually verifying with a transparent filling container 1, a liquid level detection sensor (such as a built-in type or an indirect detection type from the outside) And the temperature difference between the position corresponding to the upper liquid phase and the position corresponding to the lower liquid phase on the outer peripheral surface of the filling container, and the measured value when convection occurs It is possible to verify this change by obtaining in advance as knowledge.

[Modification of First Configuration Example of the Vaporizer]
FIG. 5 shows a modified example corresponding to the first configuration example of the vaporizer described above, in which the immersion heater 5 is disposed not in the heat medium introduction pipe 4 but in the space portion 1f (space portion 1c) close to the bottom portion 1a. By providing it in a part), the function of injecting the heat medium at a right angle to the bottom center part M of the filling container 1 is secured. By using the relatively thin heat medium introduction pipe 4, it has a function close to the nozzle 3 in the first configuration example, and by disposing the immersion heater 5 between the bottom part 1a, heating of the heat medium to be injected Can be secured. With this simple structure, it is possible to configure the vaporizer having substantially the same function as the first configuration example.

<Second configuration example of the vaporizer>
6 (A) and 6 (B) are developed forms corresponding to the first configuration example of the present vaporizer, and a space portion Sa disposed so as to be in contact with the bottom portion 1a of the filling container 1, and a filling container The space portion Sb disposed so as to be in contact with the outer peripheral portion 1 and independent of the space portion Sa, and the heat medium supplied from the heat medium supply portion 6 from the introduction portion 4b disposed in the space portion Sb to the space portion Sb. After being introduced, the flow path B discharged from the discharge port 4c provided in the space portion Sb and the heat medium supplied from the flow path B are separated from the heat medium introduction pipe 4a provided in the space portion Sa. It has the flow path A introduced into the part Sa. Similar to FIG. 12, FIG. 6A illustrates the case of the field-installed filling container 1, and FIG. 6B illustrates the case of the transport-type filling container 1, and the lower part of the filling container 1. The apparatus which can grasp | ascertain the residual amount of liquefied gas inside by measuring a weight with the load cell W arrange | positioned in FIG.

In the first configuration example, the space portion 1c that is integrated is formed with a space portion Sa and a space portion Sb that are independent from each other due to the difference in roles. In addition, the heat medium supplied from the heat medium supply unit 6 is introduced into the space Sb through the space Sb, heated by the immersion heater 5 and then sprayed by the nozzle 3, whereby the bottom of the filling container 1. Heat is concentrated on 1a. With this configuration, the following actions and functions can be obtained.
(I) By using independent spaces, independent temperature control of each of the space portions Sa and Sb is facilitated, the control accuracy can be increased, and a small temperature difference can be accurately controlled using the same heat medium. it can. As a result, an appropriate temperature difference between the ambient temperature and the liquid phase temperature of the filling container 1 and the piping for supplying air is formed, and a temperature difference between the central portion and the peripheral portion of the liquid phase portion L is created to convection in the liquid phase. By forming the film, the temperature uniformity between the liquid phase surface layer part and the other liquid phase part can be ensured.
(Ii) Introducing the heat medium whose temperature has been previously controlled into the space part Sa and introducing the supplied heat medium into the space part Sb to heat the heat medium, which has caused a temperature drop during the supply. Thus, the bottom of the container can be irradiated as a heat medium having a constant temperature higher than the control temperature.

[Modification of Second Configuration Example of the Vaporizer]
(1) FIG. 7 is a modification corresponding to the second configuration example of the present vaporizer, in which the outer periphery of the space Sb disposed so as to be in contact with the outer periphery of the filling container 1 is filled with the filling container. The space portion Sa integrated with the space disposed so as to be in contact with the bottom portion 1a of the first cover portion 1a is disposed so as to cover it. The influence of the ambient environment temperature of the filling container 1 on the space Sb can be eliminated, and the temperature control of the space Sb can be performed more accurately.

  (2) FIG. 8 is another modified example corresponding to the second configuration example of the present vaporizer, and is disposed so that the outer periphery of the space portion Sb is covered with the space portion Sa, and the bottom center portion of the bottom portion 1a. A space Sb is formed up to the vicinity of M, and a heat medium introduction pipe 4 is disposed inside the space Sa. More than the configuration of FIG. 7, the influence of the ambient temperature of the filling container 1 on the space Sb can be eliminated, and the heat medium from the nozzle 3 is injected in a narrower range of the bottom center portion M of the bottom 1a. By being able to heat input more intensively to the bottom 1a of the filling container 1, by accurately creating the temperature difference between the central part and the peripheral part of the liquid phase part L and forming convection in the liquid phase High uniformity in temperature between the liquid phase surface layer part and the other liquid phase part can be ensured.

<Configuration example of liquefied gas supply device according to the present invention>
The vaporizer is used in, for example, a liquefied gas supply apparatus for supplying a liquefied gas to a gas consuming facility that is supplied with a pipe from a filling container filled with a liquefied gas in a semiconductor manufacturing process or the like. Here, it is used for the vaporization process of the liquefied gas filled in the filling container and / or the vaporization process of the liquefied gas stored in the vicinity of the gas consuming equipment and re-liquefied after being supplied to the piping.

  FIG. 9A is a schematic diagram showing a basic configuration example (first configuration example) of a liquefied gas supply device (hereinafter referred to as “the present supply device”) according to the present invention using such a vaporizer. The low vapor pressure liquefied gas is stably vaporized, and supply without fluctuation of pressure to the gas consuming equipment (process device) 30 through the supply pipe 20 is realized. In this vaporizer, the container 1 filled with the low vapor pressure liquefied gas can be attached to and detached from the liquefied gas supply unit 10 having the vaporizer. By using this liquefied gas supply unit 10, low vapor pressure liquefied gas can be continuously supplied over a long period of time, which has been difficult due to a decrease in supply pressure due to a decrease in liquid phase temperature due to heat of vaporization because the vapor pressure is originally low. It becomes. Here, in the semiconductor manufacturing process, the process apparatus 30 includes a process chamber 31 such as CVD and PVD, and a gas control unit 32 that adjusts and supplies a predetermined pressure and flow rate thereto.

  The liquefied gas filled in the filling container 1 is vaporized by the liquefied gas supply unit 10. The liquefied gas in a gaseous state is sent to the process device 30 via the supply pipe 20. In addition, the exhaust gas from the process apparatus 30 containing the introduced liquefied gas is discharged through an exhaust gas treatment apparatus (not shown). In this supply apparatus, since the pressure decrease due to the temperature drop of the liquid phase due to the heat of vaporization is very small, it is possible to vaporize and supply the low vapor pressure liquefied gas at a temperature below room temperature, which is difficult with the conventional method. By adopting this liquefied gas vapor supply system at a temperature below room temperature, the problem of reliquefaction in the supply pipe 20 that has been a problem in the supply system that vaporizes and sends the low vapor pressure liquefied material is stable and stable. The supply pressure can be ensured and there is no problem of pipe corrosion due to reliquefaction.

  The supply apparatus can further include two sets of liquefied gas supply units 11 and 12 as shown in FIG. 9B. Basically, the configuration is the same as that shown in FIG. 9A. However, since there are two sets of the liquefied gas supply units 11 and 12, by supplying these two sets while switching them alternately, When the remaining amount of the liquefied gas in the filling container 11a of the liquefied gas supply unit 11 is reduced, the gas supply is switched to the standby liquefied gas supply unit 12 that has been kept at a constant temperature until then, The liquefied gas can be continuously supplied without having to temporarily stop every exchange.

  This supply apparatus having such a configuration is characterized by functioning under the following conditions. That is, in this supply apparatus, the set temperature (including the control temperature) of each part can be adjusted and maintained with high accuracy by effectively utilizing the functions of the vaporizer. Hereinafter, a description will be given based on FIG. It should be noted that the conditions such as the process and temperature described below are examples in which the present supply apparatus is often used, and it is needless to say that the conditions are not limited thereto.

  (A) The control temperature of the heat medium in the heat medium supply unit 6 is determined from the viewpoint of preventing re-liquefaction in the middle of the low vapor pressure liquefied gas supply pipe 20 or in the gas contact part of the process device 30. The ambient temperature in which the apparatus 30 is placed (the room temperature of the clean room is a semiconductor process). The temperature can be set to be lower than the lowest temperature of the fluctuation range of the temperature.

  (B) In the semiconductor process, the fluctuation range of the room temperature of the clean room is normally kept within 23 ± 1 to 2 ° C. Therefore, the control temperature of the heat medium is about 13 ° C. with sufficient tolerance for the risk of reliquefaction. It is preferable to make it. After that, the operation of the immersion heater 5 incorporated in the heat medium supply system is performed by the pressure of the gas phase part G of the filling container 1 being the temperature of the heat medium sent out from the heat medium supply part 6, that is, the above-mentioned. Of the liquefied gas at a temperature higher than 13 ° C. and always lower than the lower limit of the environmental temperature where the piping and the process equipment 30 are placed, specifically 15 to 16 ° C. in the case of a semiconductor factory. Saturated vapor pressure can be set.

  (C) By setting the temperature as described above, the environmental temperature of the filling container 1 is lower than the target temperature of the liquid phase portion L even when the supply of the liquefied gas is stopped. The submerged heater 5 disposed intermittently operates even when the gas supply is stopped, and convection is continuously formed in the liquid phase portion L in the filling container 1 so that the supply of the liquefied gas is continuously maintained. The Rukoto. As a result, in the case of low vapor pressure liquefied gas, it is possible to set the target temperature to “the temperature of the liquid phase surface layer at the gas-liquid interface”, which is a target of control that could not be adequately handled by the conventional method. The problem was that even if the temperature of the other part was lower than that, the heater operation stopped because the apparent pressure in the gas phase G had recovered, and the energy of the entire liquid phase was not fully recovered. Therefore, the problem that the supply pressure is apt to be abnormally lowered when the supply is resumed is solved.

  (D) As another effect of suppressing the temperature of the heat medium circulated around the outer periphery of the filling container 1 to be lower than the target temperature of the liquid phase portion L of the liquefied gas, when the supply is stopped, The heat inertia accumulated in the heat medium by the immersion heater 5 allows the liquefied gas to be replenished with heat for a while after the operation of the immersion heater 5 is stopped. is there.

[Second configuration example of the supply device]
10 (A) and 10 (B) are developed versions corresponding to the first configuration example of the supply apparatus, and the liquefied gas is supplied from the remote primary liquefied gas supply unit 13 via the supply pipe 20a. Can be replenished to the secondary liquefied gas supply device 10 (or 11, 12) in a liquid phase. As shown in FIG. 10A, the liquid phase filled in the filling container 13a is supplied to the primary liquefied gas supply unit 13 by supplying a liquid pressure feeding gas (for example, an inert gas such as nitrogen) 13b. The liquefied gas is pumped to the secondary liquefied gas supply unit 10 in a liquid state. The liquefied gas sent under pressure is supplied to the process device 30 via the supply pipe 20b by the vaporizer used in the secondary liquefied gas supply unit 11.

  In a conventional supply system that vaporizes and sends low-vapor-pressure liquefied gas, the gas flowing in the supply pipe is not only very low in supply pressure but also close to saturation vapor pressure, and is affected by temperature changes around the pipe. Since it is easy to receive, supply with long distance piping which passes through a plurality of environmental temperature regions is difficult. Therefore, these low vapor pressure liquefied gas supply devices are normally installed in the same air-conditioning environment as the process devices. When the process apparatus is a semiconductor manufacturing apparatus, a liquefied gas supply apparatus with a low vapor pressure is placed in a clean room where semiconductor consumption equipment is placed. Therefore, the replacement of the filling container 13a of the primary liquefied gas supply unit 13 as in this supply device can be performed remotely from the secondary liquefied gas supply unit 10 because it is a dangerous liquefied gas in a closed space such as a clean room. Therefore, there is a great merit in terms of safety design of the gas supply equipment and improvement of work efficiency. Further, as in the first configuration example of the supply device, as shown in FIG. 10B, a configuration having two sets of liquefied gas supply units 11 and 12 can be adopted.

[Third configuration example of the supply device]
FIGS. 11A and 11B are devices obtained by further developing the configuration corresponding to each of the second configuration examples of the supply device, and are supplied from the primary liquefied gas supply unit 13 via the supply pipe 20a. The secondary liquefied gas supply unit 10 (and 12) is remotely replenished with liquefied gas in a gaseous state. In the case of the second configuration example, it is performed in a liquid state. In this supply device according to the third configuration example, the liquefied gas sent in the gas phase state is placed in the vicinity of the process device 30. The liquefied gas is supplied again by the liquefied gas supply unit 11 and stored in a liquefied state. The liquefied gas is stored again as a liquid phase, vaporized again by the vaporizer, and sent to the process apparatus 30 in a gaseous state via the supply pipe 20b. It is a gas supply device.

  Specifically, as shown in FIG. 11A, the liquefied gas filled in the filling container 13a is vaporized by the primary liquefied gas supply unit 13. The liquefied gas in a gaseous state is sent to the secondary liquefied gas supply unit 10 (or 11, 12) via the supply pipe 20a. The supplied liquefied gas is liquefied again by the reliquefaction means (not shown) in the secondary liquefied gas supply unit 10 (or 11, 12) and stored in a liquid state by the storage means (not shown). . The stored liquefied gas is vaporized by vaporizing means (not shown). The liquefied gas in a gaseous state is sent to the process device 30 via the supply pipe 20b. In addition, the exhaust gas from the process apparatus 30 containing the introduced liquefied gas is discharged through an exhaust gas treatment apparatus (not shown). In the case of the filling container 1D delivered from the liquefied gas manufacturer, the installation / removal operation is performed only by the primary liquefied gas supply unit 13, and therefore the place where the process apparatus 30 where the general worker works (semiconductor) In the case of a manufacturing process, in a clean room, the dangerous work of opening the piping to the atmosphere does not have to be performed. This makes it possible to completely separate and centrally supply all liquefied gas, including low vapor pressure liquefied gas, from the workplace (clean room, etc.), which was impossible in the past, dramatically increasing safety and improving work efficiency. Can be planned.

  The secondary liquefied gas supply unit 10 once liquefied the liquefied gas in the gas state fed from the primary liquefied gas supply unit 13 and the supply pipe 20a and once stored as a liquefied gas in the liquid state. It has a function of vaporizing the liquefied gas again and supplying it to the process apparatus 30 in a gaseous state. In this supply apparatus, such a function can be ensured by using the liquefying means, the storage means, and the above-described vaporizing apparatus. Further, similarly to the first and second configuration examples of the supply device, as shown in FIG. 11B, a configuration having two sets of liquefied gas supply units 11 and 12 can be adopted.

  In the above description, a method for vaporizing a liquefied gas such as a semiconductor or special gas for semiconductors used in a semiconductor or FPD manufacturing process, a vaporizer, and a liquefied gas supply device using the method have been described. The present invention is not limited, and can be applied to liquefied gas for various processes or heat treatment processes for various liquids. Further, when a plurality of temperature conditions are required, it is useful as an apparatus that supplies only a refrigerant having a corresponding temperature, and is particularly useful for a manufacturing process that requires heat treatment under a plurality of temperature conditions. For example, a processing means used for switching between cooling and heating in a process such as gas adsorption processing and purification processing is applicable.

Schematic which shows the basic structural example of the vaporization apparatus (this vaporization apparatus) which concerns on this invention Explanatory drawing illustrating temperature-saturated vapor pressure line of liquefied gas Explanatory drawing which illustrates the convection in the liquid phase inside the filling container in this vaporizer Explanatory drawing illustrating pressure behavior in this vaporizer Explanatory drawing which shows the modification of the 1st structural example of this vaporization apparatus. Explanatory drawing which shows the 2nd structural example of this vaporization apparatus. Explanatory drawing which shows the modification of the 2nd structural example of this vaporization apparatus. Explanatory drawing which shows the modification of the 2nd structural example of this vaporization apparatus. Explanatory drawing which shows the basic structural example of the liquefied gas supply apparatus (this supply apparatus) which concerns on this invention Explanatory drawing which shows the 2nd structural example of this supply apparatus. Explanatory drawing which shows the 3rd structural example of this supply apparatus. Schematic illustrating a liquefied gas vaporizer according to the prior art Schematic illustrating a liquefied gas supply apparatus according to the prior art

Explanation of symbols

1, 1A, 1B Filling container 1a Bottom 1b Outer peripheral part 1c, Sa, Sb Space 1d Filling port 1e Outlet 2 Jacket 2a Outlet 3 Nozzle 3a Narrow part 4 Heat medium introduction pipe 5 Immersion heater (heating part)
6 Heat medium supply section 7 Pressure sensor 8 Liquefied gas pressure signal 9 Temperature controller 10-13 Liquefied gas supply unit 20, 20a, 20b Supply piping 30 Gas consumption equipment (process device)
A, B Channel G Gas phase part L Liquid phase part M Bottom center

Claims (9)

A method for vaporizing a liquefied gas, wherein a liquefied gas in a gas phase portion is sent to a consuming facility from a liquefied gas filling container stored in a state where the liquid phase and the gas phase coexist,
A temperature-controlled heat medium is circulated in a space disposed so as to be in contact with the bottom and outer periphery of the filling container,
In both the state of supplying the liquefied gas and the state of stopping the supply of air, a heating unit disposed in a space close to the bottom of the space or in a heat medium introduction pipe provided in the space By adjusting the amount of heat applied to the liquefied gas, the gas phase pressure inside the filling container is adjusted to be higher than the saturated vapor pressure of the liquefied gas at the control temperature of the heat medium. Vaporization method. In a method for vaporizing a liquefied gas, a liquefied gas filled from a liquefied gas container stored in a state where the liquid phase and the gas phase coexist are sent to the consuming equipment.
A temperature-controlled heat medium is circulated to two independent spaces Sa and Sb arranged so as to be in contact with each of the bottom and the outer periphery of the filling container,
In both the state of supplying the liquefied gas and the state of stopping the supply of air, a heat medium supplied to the space portion Sa in contact with the bottom portion is installed in the space portion Sa or in the space portion Sa. By controlling the amount of heat applied to the heating unit disposed inside the heat medium introduction pipe, the gas phase pressure inside the filling container is higher than the saturated vapor pressure of the liquefied gas at the control temperature of the heat medium. A method for vaporizing a liquefied gas, wherein the gas is adjusted to be high.   The center of the bottom of the filling container is selectively irradiated with the heating medium heated by the heating unit provided inside the heating medium introduction pipe and delivered from the heating medium introduction pipe. To increase the heat input to the liquefied gas at the center of the filled container from the other bottom, and generate convection in the liquid phase that rises at the center of the liquid phase and descends at the outer periphery of the liquid phase. The method for vaporizing a liquefied gas according to claim 1 or 2. A liquefied gas vaporizer that feeds the liquefied gas in the vapor phase portion to the consuming equipment from a liquefied gas filling container stored in a state where the liquid phase and the gas phase coexist,
A heat medium supply unit that circulates and supplies the heat medium with temperature control;
A space portion disposed so as to be in contact with a bottom portion and an outer peripheral portion of the filling container;
A space close to the bottom of the space or a heating unit disposed in a heat medium introduction pipe provided in the space;
While having a control unit to control these,
In both the state where the liquefied gas is supplied and the state where the supply of air is stopped, the control unit determines the control temperature and supply flow rate of the heat medium in the heat medium supply unit, and the amount of heat applied to the heating unit. An apparatus for vaporizing a liquefied gas, wherein the vapor phase pressure inside the filling container is adjusted so as to be higher than a saturated vapor pressure of the liquefied gas at a control temperature of the heat medium. In the liquefied gas vaporizer for sending the liquefied gas in the gas phase section to the consuming equipment from the liquefied gas filling container stored in a state where the liquid phase and the gas phase coexist,
A heat medium supply unit that circulates and supplies the heat medium with temperature control;
A space Sa disposed so as to be in contact with the bottom of the filling container;
A space portion Sb that is disposed in contact with the outer peripheral portion of the filling container and is independent of the space portion Sa;
After the heat medium supplied from the heat medium supply part is introduced into the space part Sb from the introduction part provided in the space part Sb, the flow discharged from the discharge port provided in the space part Sb. Road B,
A flow path A in which the heat medium delivered from the flow path B is introduced into the space portion Sa from a heat medium introduction pipe disposed in the space portion Sa;
A heating unit disposed in the heat medium introduction pipe or in the space Sa,
The liquefaction characterized in that the heating medium supplied from the flow path B is additionally heated by the heating unit in both the state of supplying the liquefied gas and the state of stopping the supply of air. Gas vaporizer.   In the space portion in contact with the bottom portion of the filling container, a nozzle that is connected to the heat medium introduction tube and injects the heat medium at a right angle to the wall surface of the space portion in contact with the central portion of the bottom surface is disposed. The liquefied gas vaporization apparatus according to claim 4 or 5, wherein a heating unit is disposed inside.   A pressure detection unit is provided in connection with the gas phase part of the filling container, and has a function of controlling the amount of heat applied to the heating unit and / or the flow rate of the heat medium using the measured value as an index. The liquefied gas vaporizer according to any one of claims 4 to 6.   The liquefied gas vaporizer according to any one of claims 4 to 7, wherein a thickness of a central portion of the bottom surface of the filling container is thinner than other portions. A liquefied gas supply device that feeds liquefied gas to a gas consuming facility that is fed from a filling container filled with liquefied gas and separated from the container,
Using the liquefied gas vaporizer according to any one of claims 4 to 8,
Vaporization treatment of the liquefied gas filled in the filling container,
And / or an apparatus for supplying a liquefied gas, wherein the liquefied gas stored in the vicinity of the gas consuming equipment and re-liquefied after being supplied to the pipe is stored.

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