JP4795825B2 - Gas supply apparatus and gas supply method - Google Patents

Description

  The present invention relates to a gas supply method that suppresses a temperature drop of a gas and supplies it stably and for a long time when the high-pressure gas filled in the gas container is depressurized in multiple stages and supplied to the user. The present invention relates to a gas supply device for realizing the above.

In the manufacturing process of semiconductors and chemical products, various process gases and etching gases are continuously supplied from high-pressure gas containers to these manufacturing apparatuses through piping. The gas to be supplied is generally at a pressure of about several kgf / cm ² (0.1 to 1 MPa) (in the present invention, unless otherwise noted, it means the total pressure). On the other hand, in a gas container, it is compressed at a pressure of about several MPa to several tens of MPa and stored in a high-pressure gas or liquid state. For this reason, the pressure of the high-pressure gas is adjusted by the pressure reducing valve and supplied to the user.

  The pressure difference between the high pressure side (primary side) and the low pressure side (secondary side) of the pressure reducing valve is several to several tens of times as described above. Expansion) and / or Joule-Thomson expansion (adiabatic irreversible expansion). Adiabatic expansion is an isentropic change and is a phenomenon that always causes a decrease in temperature for all gases including the ideal gas. When the flow rate of gas passing through the pressure reducing valve is high, an expansion phenomenon close to adiabatic expansion occurs. On the other hand, when the flow velocity passing through the pressure reducing valve is slow, an expansion phenomenon close to Joule-Thomson expansion occurs. Joule-Thomson expansion is an isenthalpy change, and the temperature of the gas does not change in an ideal gas, but the temperature increases or decreases in a real gas. This is called the Jules Thomson effect.

  Here, the ratio of the temperature change to the pressure drop when the Joule-Thomson effect occurs is called the Joule-Thomson coefficient, and is defined by the following formula (1). T is the gas temperature, p is the pressure, and h is the specific enthalpy.

From equation (1), it can be seen that when the Joule-Thomson coefficient is positive, the temperature decreases as the gas pressure drops. Further, when the formula (1) is modified, the following formula (2) is derived. V is the volume of gas and C _p is the constant pressure heat capacity.

In equation (2), since pV = RT always holds for the ideal gas, the value in [] on the right side is zero, and the Joule-Thomson effect does not occur. However, in the real gas, the value in [] on the right side does not become zero, and becomes positive when the temperature T is high, and conversely becomes negative when the temperature T is low.
The temperature between the positive and negative boundaries is called the reversal temperature. If this temperature is above room temperature, the Joule-Thomson coefficient in equation (1) is positive, that is, when the high-pressure gas at room temperature is expanded enthalpy by the pressure reducing valve, The temperature drops. Conversely, for gases whose reversal temperature is below room temperature, the Joule-Thompson effect that occurs during decompression works in a direction that raises the temperature of the gas. The temperature drop is partially or completely offset, and the temperature change of the gas and the pressure reducing valve becomes small.
The Joule-Thomson coefficient varies depending on the gas temperature and pressure as well as the type of gas.

Here, silane (SiH ₄ ), nitrogen trifluoride (NF ₃ ), silicon fluoride (SiF ₄ ), Freon 116 (C ₂ F ₆ ), or a main component of air as a process gas in a semiconductor manufacturing process. Since the gases such as nitrogen (N ₂ ), oxygen (O ₂ ), and argon (Ar) all have a reversal temperature equal to or higher than room temperature, the joule generated when the gas is extracted from the high-pressure gas container at room temperature is decompressed.・ Thomson effect works in the direction of lowering the gas temperature.

  When the high-pressure gas filled in the gas container is supplied by reducing the pressure with a pressure reducing valve, an intermediate state between adiabatic expansion and Joule-Thomson expansion occurs. The influence of temperature drop due to Thomson expansion becomes dominant. The present invention ignores the influence of adiabatic expansion of the decompressed gas and solves the problem caused by the temperature drop of the gas due to Joule-Thomson expansion.

  On the other hand, there are pressure reducing valves based on various operating principles, but in general, a movable part called a seat and a diaphragm is balanced and held by two springs for pressure regulation and sealing, and from the primary side. While maintaining the desired secondary side pressure while suppressing the inflow of the high pressure gas by the biasing force of the spring. For this reason, if the pressure reducing valve is cooled by the above-described adiabatic expansion and / or Joule-Thompson expansion and condensation of water vapor in the ambient air or freezing occurs in the worst case, the mobility of the seat or diaphragm is impaired and supplied. It is difficult to accurately control the gas pressure and gas flow rate. In general, if the metal pressure reducing valve and the surrounding piping surface are left in a dewed state for a long time, the strength of the metal is reduced due to corrosion, and there is a risk of cracking or cracking due to stress.

  For this reason, in a conventional pressure reducing valve, it has been generally performed to maintain a predetermined temperature by constantly heating it with an electric heater or hot water. However, depending on the type of gas, the effect of temperature drop due to the Joule-Thomson effect was significant, and the amount of heat to be supplied to the pressure reducing valve was enormous. Therefore, for example, like the pressure regulator described in Patent Document 1, the pressure reducing ratio of the gas in each stage is suppressed low by configuring the pressure reducing valve in two stages, and the temperature drop due to adiabatic expansion and / or Joule-Thomson expansion is suppressed. Attempts have been made to suppress it.

JP-A-10-020939

  However, even when the above two-stage pressure regulator is used, when a high-pressure gas with a high Joule-Thomson coefficient is decompressed and supplied to the user at a large flow rate, Especially in the first stage, the temperature drops drastically and the water vapor in the atmosphere easily condenses or freezes, hindering the normal operation of the mechanism and providing a stable gas supply for a long time. It was difficult to continue.

The principle of such cooling of the pressure reducing valve will be described with reference to the drawings. FIG. 6 shows a pressure-specific enthalpy diagram (Ph diagram) of nitrogen trifluoride (NF ₃ ) gas and a state in which NF ₃ gas with a filling pressure of 10.8 MPa is depressurized in two stages to 0.45 MPa. (Hereinafter referred to as a decompression profile).

The state a1 ′ is an initial state of the gas filled in the gas container at a high pressure, the atmospheric temperature is 30 ° C. (T1 ′), and the initial pressure is 10.8 MPa (P1 ′) based on the internal pressure of the container. The intermediate pressure, which is the secondary pressure of the first pressure reducing valve, is set to 2.0 MPa (P2 ′), the gas is derived from the gas container, and the pressure is reduced by isoenthalpy (Joule Thomson) expansion. State a2 ′. In such a state, the gas is cooled to about −25 ° C. (T2 ′) by the Joule-Thomson effect. From this state a2 ′, the state in which the gas reaches 30 ° C. (T3 ′ = T1 ′) while maintaining the equal pressure (P3 ′ = P2 ′) by heating with a heater or the like is the state a3 ′.
Further, the secondary pressure of the second-stage pressure reducing valve is set to 0.45 MPa (P4 ′) that is the supply pressure to the user, and the gas in the state a3 ′ is decompressed by isoenthalpy expansion to obtain the state a4 'Is.

  However, when the two-stage pressure reduction of the high-pressure gas is attempted according to the above-described pressure reduction profile, since the gas cooling in the state a2 ′ is excessive, the thermal equilibrium temperature of the first-stage pressure reducing valve placed in a normal temperature atmosphere is about 0 ° C. Or the temperature falls below this, and the water vapor in the atmosphere is condensed or frozen, and the drive of the pressure reducing valve is hindered. In fact, the gas state change according to the pressure reducing profile is not performed in the portion indicated by the broken line in FIG. There is a problem. That is, in the first stage of the two-stage pressure reducing valve, the temperature of the gas drastically drops to about −25 ° C. due to the Joule-Thomson effect, so that the first stage driving part is frozen soon, and the gas introduced into the pressure reducing valve thereafter is one stage. This is because the pressure reducing valve of the eye is rapidly reduced from the state a1 ′ (initial pressure P1 ′) to the state a4 ″ (user supply pressure P4 ′) with almost no pressure reduction. When such a rapid pressure reduction is performed by the second-stage pressure reducing valve, the gas temperature reaches −40 ° C., as shown by the solid line in FIG. The part will also freeze soon and control of the entire gas supply will be disabled.

  In order to solve the above-mentioned problem that the drive of the pressure reducing valve is obstructed, a heating device such as a heater is provided in the first stage pressure reducing valve itself, and a continuous and large amount of the valve drive unit is prevented from condensation or freezing. It is necessary to supply heat to this.

  Such a problem can be alleviated to some extent by setting the first pressure reduction level higher. That is, when the secondary pressure (P2 ′) of the first-stage pressure reducing valve is made higher than the above setting (for example, 2.0 MPa) (for example, P2 ′ is set to 6.0 MPa), the pressure is generated in the first-stage pressure reducing valve. It is possible to suppress the Joule-Thomson effect, and to moderate the temperature drop caused by such a valve to some extent. However, in this case as well, since a severe temperature drop occurs in the second-stage pressure reduction, the same problem that the second-stage pressure reducing valve needs to be continuously and massively heated by a heater or the like arises. .

  Based on such problems, the present invention reduces the temperature drop of the gas due to the Joule-Thompson effect when supplying the user with the high-pressure gas filled in the gas container by depressurizing the gas in multiple stages. It is an object of the present invention to provide a gas supply method that enables supply and reduces the supply of heat by heater power or hot water as much as possible, and a gas supply device that realizes the method. Another object of the present invention is to provide a gas supply method and a gas supply device that can continue such gas supply for a long time even when the filling pressure in the gas container is lowered.

  In the present invention, when the high-pressure gas filled in the gas container is depressurized in multiple stages, an ideal depressurized state in the middle stage is determined from the state quantity before depressurization of the gas and the state quantity after depressurization. We paid attention to the fact that by reducing the pressure of the gas according to the reduced pressure profile, the temperature drop is suppressed and the gas can be supplied for a long time.

That is, the gas supply device according to the present invention includes:
(1) a gas container filled with gas under pressure;
Piping for circulating the gas derived from the gas container;
A pressure regulator that is provided in the pipe, introduces the flowing gas from the primary side, and further reduces the pressure so that the pressure can be adjusted, and discharges the gas from the secondary side;
A pressure reducing valve that is provided on the secondary side of the pressure regulator and depressurizes the circulating gas;
Gas data acquisition means for acquiring data on the primary gas state quantity and the secondary gas state quantity data of the pressure reducing valve, respectively, and the adjustment based on the acquired gas state quantity data. A controller comprising target pressure setting means for determining a target value of the secondary pressure of the pressure device, and pressure adjusting means for adjusting the secondary pressure of the pressure regulator in accordance with the target value;
A gas supply device having:
(2) The atmosphere in which the state quantity of the gas on the primary side of the pressure adjusting device is input by the gas data input means provided in the controller, and the pressure of the gas measured by a pressure sensor provided in the gas supply device Temperature, and
The gas supply device according to (1), wherein the state quantity of the gas on the secondary side of the pressure reducing valve is a user supply pressure input by the gas data input means;
(3) The pressure adjusting device is driven by the pressure adjusting means to switch the gas flow path to one or more of the plurality of pressure reducing lines, each having a plurality of orifices having different diameters arranged in parallel. A gas supply device according to (1) or (2), comprising: a switching means;
(4) The pressure regulating device is a needle valve that inserts a needle into the flow path of the circulating gas, and
The gas supply device according to (1) or (2), wherein the insertion depth of the needle can be continuously adjusted by the pressure adjusting means;
(5) The gas supply device according to (4), further including a temperature sensor that measures the temperature of the needle valve;
(6) The gas supply device according to any one of (1) to (5), further including a temperature sensor that measures the temperature of the gas on the secondary side of the pressure regulator, or a pressure sensor that measures the pressure of the gas;
Is the gist.

The gas supply method according to the present invention includes:
(7) A gas supply method for depressurizing a gas filled in a gas container in multiple stages and supplying the gas to a user,
Based on the state quantity of the gas pressurized and filled in the gas container and the state quantity of the gas decompressed in multiple stages, a target decompression level of the gas in the middle stage is set, and according to the target decompression level A gas supply method comprising depressurizing the gas;
(8) The state quantity of the gas pressure-filled in the gas container is the temperature and pressure of the gas,
The gas supply method according to (7), wherein the state quantity of the gas decompressed in multiple stages is the pressure of the gas;
(9) The target decompression level of the gas is
The gas supply method according to the above (7) or (8), wherein both the temperature of the gas decompressed in multiple stages and the temperature of the gas in the intermediate stage are set to a predetermined temperature or higher;
(10) The target decompression level of the gas is
The gas supply method according to any one of (7) to (9), wherein the temperature of the gas decompressed in multiple stages and the temperature of the gas in the intermediate stage are equalized;
(11) When the filling pressure in the gas container is lowered, the target decompression level of the gas in the intermediate stage is reset, and the decompression of the gas is performed according to the reset target decompression level. The gas supply method according to any one of (7) to (10) above;
(12) The temperature or pressure of the gas decompressed in one stage or multiple stages is measured, and when the temperature or pressure reaches a predetermined value, the target decompression level of the gas in the middle stage is reset and applied. The gas supply method according to any one of (7) to (11) above, wherein the gas is depressurized at an intermediate stage according to the reset target depressurization level;
Is the gist.

further,
(13) The controller is
Gas remaining amount detecting means for acquiring the remaining amount data of the gas filled in the gas container, and gas reduction rate acquiring means for acquiring a decrease rate of the remaining amount of the filled gas based on the remaining amount data of the gas; The gas supply device according to any one of (1) to (6), comprising:
(14) The gas supply device according to any one of (1) to (6) or (13), wherein a buffer tank is provided between the secondary side of the pressure regulator and the primary side of the pressure reducing valve;
(15) The gas supply device according to (5) or (6), comprising a temperature sensor,
Two or more gas lines each including the gas container, piping, pressure regulator, and the temperature sensor, and a switching device for closing or opening the gas line, and
The controller has temperature data acquisition means for acquiring temperature data from the temperature sensor, and when the temperature data is equal to or less than a predetermined value, drives the switching device to change the gas flow path to any one of the gas lines. A gas supply device comprising line switching means for switching as described above;
(16) The pressure regulator is
A plurality of pressure reducing lines each provided with an orifice and an opening / closing valve that is opened and closed by the pressure adjusting means are provided in parallel,
The gas supply apparatus according to any one of (1) to (3), wherein the orifice has a different diameter for each decompression line;
(17) The above (1) to (6) or (13) to (16) provided with a heating means for heating the circulating gas between the secondary side of the pressure regulator and the primary side of the pressure reducing valve A gas supply device according to any one of the above;
(18) The gas supply device according to any one of (1) to (6) or (13) to (17), wherein an automatic stop valve is provided on the primary side of the pressure regulating device;
(19) The gas supply method according to any one of (7) to (10), wherein the compression coefficient of the gas filled in the gas container is 0.7 or less;
(20) The gas supply method according to any one of (7) to (11), wherein the gas is depressurized by enlarging or reducing the cross-sectional area of the gas flow path;
(21) When the flow rate of the gas supplied to the user exceeds a predetermined value, the target decompression level of the gas in the middle stage is reset, and the decompression of the gas is performed according to the reset target decompression level. The gas supply method according to any one of (7) to (12), (19), or (20), wherein:
(22) The gas supply method according to (21), wherein the flow rate of the gas is calculated based on a change rate of the remaining amount of the gas filled in the gas container;
(23) Prepare two or more gas lines for depressurizing the gas filled in the gas container in multiple stages and supplying it to the user,
In one gas line, the gas is supplied to the user by the gas supply method described in any one of (7) to (12) or (19) to (22), and the pressure is reduced in multiple stages in the gas line. A gas supply method, wherein the gas flow path is switched to another gas line when the temperature of the gas or the temperature of the gas decompressed in the middle stage becomes a predetermined value or less;
(24) The gas supply method according to any one of (7) to (12) or (19) to (23) above, wherein the gas in the middle stage is heated by a heating means;
The object of the present invention can also be achieved.

  According to the gas supply device and the gas supply method according to the present invention, when the high-pressure gas filled in the gas container is depressurized in multiple stages and supplied to the user, an ideal target depressurization level is set by the pressure regulator in the middle stage. By realizing the decompression, it becomes possible to balance the temperature of the gas after decompression in each stage. This avoids the conventional problem that the temperature of the gas drops due to the Joule-Thompson effect, particularly in the first-stage pressure reduction. For this reason, even when a gas with a high Joule-Thomson coefficient is continuously supplied to the user, the amount of heat supplied by heater power or hot water is greatly reduced, while the temperature drop of the gas and the resulting condensation on the pressure reducing valve, etc. And freezing can be prevented, and this can be continued stably for a long time.

  Further, in the gas supply device and the gas supply method according to the present invention, it is possible to adjust the target value of the decompression level of the gas at each stage according to the state quantity of the gas on the primary side of the pressure regulating device. Even when the filling pressure or temperature in the gas container decreases due to continuous supply, the target value can be reset following this. Thereby, the temperature drop is less than that of the conventional two-stage pressure reducing valve, and stable and continuous gas decompression supply becomes possible.

  The first embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a system diagram of a gas supply apparatus according to the present embodiment. 10 is a gas supply device, 11 is a gas container, 12 is piping, 20 is a parallel orifice device as an example of a pressure regulating device, 30 is a pressure reducing valve, 40 is a controller, and 43 is a weight as an example of a gas remaining amount detecting means. The total, 41a and 41b are temperature sensors, and 42a and 42b are pressure sensors. In the drawing, a solid line represents a gas flow path, and a broken line represents a transmission path of a control signal processed by the controller 40.

  The gas supply device 10 is a device that realizes the gas supply method according to the present invention by using the gas supply device 10 and can take out the high-pressure gas from the gas container 11 and reduce the pressure to supply it to the user stably for a long time. It is what. The user is a gas-using facility such as a semiconductor manufacturing device or a chemical device, but can also include an experimental facility or a combustion device. The gas supply device 10 includes a pipe 12 that connects the gas container 11 and the gas use facility, a pressure regulator that reduces the pressure of the gas flowing through the pipe so that the pressure can be adjusted, and a gas on the downstream side (secondary side) of the pressure regulator. Is further provided with a pressure reducing valve 30 for further reducing the pressure and a controller 40 for controlling the pressure reducing level in the pressure regulator.

  The present invention sets an ideal target pressure reduction level as the pressure reduction level of the gas by the pressure regulator when supplying high pressure gas in multiple stages and supplies it to the user. By adjusting the secondary pressure, the gas is prevented from protruding and dropping in temperature due to the Joule-Thomson effect in any one of the multiple pressure reduction stages. As a specific example of the pressure regulating device, in the present embodiment, a system in which a plurality of pressure reducing lines having orifices having different diameters is appropriately switched by an on-off valve is given.

  In the present embodiment, a system in which a set of pressure regulating devices is provided and the pressure reducing valve 30 provided on the secondary side thereof is combined with the high pressure gas in two stages is exemplified. However, if two pressure regulators are provided in series in the gas line, three stages of pressure reduction are performed together with the pressure reducing valve 30, so that the influence of the Joule-Thomson effect of the gas in each stage can be further alleviated. . The same applies when three or more pressure regulators are arranged in series. Hereinafter, in the present invention, a case will be described in which a set of pressure adjusting devices is provided and two-stage pressure reduction is performed together with the pressure reducing valve 30 as an example.

  A parallel orifice device 20 which is a specific example of a pressure regulating device capable of decompressing gas so that the secondary side pressure can be adjusted is configured by providing a plurality of decompression lines 21a to 21c in parallel. The decompression line 21a (21b, 21c) includes an orifice 23a (23b, 23c) having a different diameter and an on-off valve 22a (22b, 22c) for switching the gas flow path to one or more of the decompression lines 21a to 21c. have. In the present embodiment, for the sake of convenience, the orifice diameter is set to 23a <23b <23c. The number of decompression lines is not particularly limited as long as it is two or more. However, the target decompression level of the gas, which will be described later, can be finely controlled, and a stable supply of gas can be realized for a long time, and the apparatus can be simplified. From this point of view, it is preferable that the number is three or more, preferably three to five. Note that the cross-sectional area of the orifice (23c) having the maximum diameter is made equal to the cross-sectional area of the pipe 12, that is, in one pressure reducing line, the pressure on the primary side (= filling pressure in the gas container) is not reduced. It may be possible to pass through.

In addition, as a specific example of the switching means for switching the gas flow path to any one or more of the decompression lines 21a to 21c, as shown in FIG. 1, other than by opening and closing of on-off valves 22a to 22c provided on each line Alternatively, a switching valve may be provided at the branch portion of the decompression line to switch the switching valve. In the case where an on-off valve is provided in each decompression line, gas can flow through the plurality of decompression lines by simultaneously opening the plurality of on-off valves. Thereby, for example, when four decompression lines are provided, a gas line can be selected from a maximum of 15 combinations, and a more precise decompression level can be set in the parallel orifice device 20. Further, when the gas line is selected from any one of the pressure reducing lines by the switching valve, an opening / closing valve for each pressure reducing line becomes unnecessary, so that the number of parts can be reduced and the apparatus can be simplified.
As long as a predetermined decompression level is realized between the primary side and the secondary side of each decompression line, each decompression line 21a to 21c is provided with a plurality of orifices having the same or different diameters in series. Also good.

  The decompression profile (states a1 to a4) according to the present embodiment is indicated by white circles and solid lines using the Ph diagram shown in FIG. That is, by setting 5.1 MPa (P2) as the first pressure reduction level, the gas temperature (T2) after the first pressure reduction and the gas temperature (T4) after the second pressure reduction are made equal. be able to. As a result, the gas temperatures (T2, T4) after depressurization are both about 2 ° C., and it is possible to avoid dew condensation and freezing of water vapor while balancing the degree to which the pressure regulator and the pressure reducing valve are cooled. . This solves the problem caused by the gas pressure after depressurization in the first stage has reached about minus 25 ° C. in the decompression profile (a1 ′ to a4 ′) in the conventional two-stage pressure reducing valve shown in FIG. can do.

  The gas state a1 before decompression determined by the filling pressure (P1) and the atmospheric temperature (T1) in the gas container and the pressure (P4) of the gas (state a4) that is decompressed in two stages and supplied to the user are preliminarily determined. In the determined system, the temperature (T2) and pressure (P2) of the gas (state a2) after the first stage depressurization, and the gas (state a3) immediately before the second stage of depressurization after the temperature is recovered. A total of five state quantities of the temperature (T3) and the pressure (P3) of the gas and the temperature (T4) of the gas (state a4) after the second decompression are undecided.

In contrast,
The first-stage and second-stage decompressions are performed in an enthalpy manner, that is, (1) h1 = h2, (2) h3 = h4 (where h1 to h4 are specific enthalpies in states a1 to a4, respectively). ;
The temperature recovery from the state a2 to the state a3 is performed at a constant pressure, that is, (3) P2 = P3;
Recovering to ambient temperature in state a3, ie (4) T3 = T1;
Furthermore, the temperature of the gas after each decompression is made equal, ie (5) T2 = T4;
By adding these five conditions, the decompression profile is uniquely determined, and the pressure (P2) after the first decompression, which is the target decompression level, can be determined.

In the present invention, instead of the above condition (5), T2 and T4 may be set to a predetermined temperature (for example, 0 ° C. or the condensation temperature of the atmosphere) or higher. In this case, the decompression profile is not necessarily unique, and the pressure P2 can be appropriately selected from a predetermined range. In addition, it may be a condition that T2 and T4 are within a predetermined temperature difference (for example, ± 2 ° C.), and each allowable temperature may be set based on a condition such as a difference in heat capacity between the pressure regulator and the pressure reducing valve. It may be determined and set as T2 or T4.
Further, when the gas does not recover to the ambient temperature during the period from the state a2 to the state a3, instead of the condition (4), a predetermined value is obtained from parameters such as the temperature (T2) after the first stage depressurization and the gas flow rate. The temperature T3 may be determined based on the following formula.

  A method for inputting these parameters and a method for setting the target pressure reduction level in the controller 40 will be described later.

In the gas supply method according to the present embodiment in which the temperature of the gas after each decompression is made equal, the set target decompression level can be realized by enlarging or reducing the cross-sectional area of the gas flow path. Specifically, this is realized by selecting one or more gas lines having an orifice having a predetermined diameter among the plurality of decompression lines as a flow path.
That is, for example, when the decompression of the gas in the parallel orifice device 20 (first stage) is insufficient and the Joule-Thomson effect of the gas in the decompression valve 30 (second stage) is likely to be excessive, the diameter is further increased. By selecting a gas line having an orifice 23b or 23a that can reduce the gas flow rate small, the pressure reduction ratio in the first stage can be increased. Thereby, the temperature of the gas of the state a2 and the state a4 in a decompression profile can be balanced.

  On the other hand, when the decompression of the first stage gas is excessive and the cooling of the parallel orifice device 20 becomes intense, the decompression line 21c or 21b including the orifice 23c or 23b having a large diameter is used to reduce the first stage decompression. Can be brought close to the target decompression level.

In the present invention, the pressure regulator performs pressure reduction according to the target pressure reduction level. However, the actual pressure reduction level of the supply gas in the pressure regulator does not need to exactly match the target pressure reduction level, as long as the temperature of the gas after pressure reduction is within an error range of about several degrees Celsius from the target value, It has a predetermined allowable width.
Specifically, since the number of pressure reducing lines provided in the parallel orifice device 20 is finite, depending on the set value of the target pressure reducing level, it may be difficult to realize this strictly. The object of the present invention can be satisfactorily achieved by selecting, as the gas flow path, one having an orifice having an optimum diameter from among a plurality of decompression lines. In such a case, for example, the temperature or pressure of the gas on the secondary side of the parallel orifice device 20 is monitored by the temperature sensor 41b or the pressure sensor 42b, and these measured values are the state quantities (T2 or P2) at the set target decompression level. It is also preferable to switch the pressure-reducing line by opening and closing the on-off valves 22a to 22c as appropriate by, for example, open loop control by the controller 40 so as to match or be close to each other.

  As another example of realizing the function of the pressure regulating device according to the present invention, a needle valve 25 is provided which inserts a needle into a gas flow path and continuously increases or decreases the cross-sectional area of the flow path. FIG. 2 is a system diagram of the gas supply device 10 according to the second embodiment of the present invention using the needle valve 25 as a pressure regulator. The gas sensor 11, the pipe 12, the pressure reducing valve 30, the controller 40, the temperature sensor 41 a and the pressure sensor 42 a for measuring the state quantity of the gas on the primary side of the needle valve 25, and the pressure on the secondary side of the pressure reducing valve 30 are measured. The pressure sensor 42b to be used is the same as that in the first embodiment.

In the needle valve 25, the insertion depth of the needle can be continuously adjusted by the control of the controller 40.
In the first embodiment, the parallel orifice device 20 that selects one or more from a finite number of pressure reduction lines and performs the first-stage pressure reduction performs pressure reduction according to the target pressure reduction level. In the embodiment, since the needle valve 25 capable of continuously adjusting the cross-sectional area of the gas flow path is used, the target pressure reduction level can be realized with higher accuracy. Thereby, when performing the two-stage decompression of the high-pressure gas in accordance with the decompression profile shown in FIG. 3, the temperature (T2, T4) of the gas after decompression of the first stage and the second stage is more accurately matched, and the needle valve 25 or Excessive cooling of the pressure reducing valve 30 can be avoided.
In addition to the needle valve, a pressure reducing device including a spring and a diaphragm or a ball valve may be used as the pressure adjusting device as long as the pressure adjusting level can be controlled.

  In addition, unlike an orifice that does not have an adjustment mechanism for reducing the pressure of the gas, the needle valve 25 has a drive mechanism that adjusts the elevation depth of the needle. Therefore, condensation or freezing of water vapor is prevented so as not to hinder the smooth drive. It is preferable to avoid it. Therefore, in the gas supply device 10 according to the present embodiment, the temperature of the needle valve 25 may be measured by the temperature sensor 41b. The part of the needle valve 25 that measures the temperature by the temperature sensor 41b is not particularly limited. For example, by measuring the temperature of the drive mechanism, the temperature of the part that may impair the function of the needle valve is directly and accurately monitored. be able to. Further, by measuring the temperature in the vicinity of the outlet on the secondary side, the most easily cooled part of the needle valve can be monitored. Further, by measuring the surface temperature of the pressure reducing valve, it is possible to monitor the temperature at the boundary with the atmospheric air, which is the part where condensation is most likely to occur. The temperature of any of the above points, or a simple or weighted average of the temperatures of any of a plurality of points may be used as the needle valve temperature.

  In the present embodiment, when determining the first stage target pressure reduction level from the temperature and pressure of the gas on the primary side of the needle valve 25 and the pressure on the secondary side of the pressure reducing valve 30, the first stage and the second stage are determined. In addition to the condition that the temperature (T2, T4) of the gas after depressurization is close or equal, a condition may be added so that the temperature of the needle valve 25 monitored by the temperature sensor 41b does not fall below, for example, the dew condensation temperature of the atmosphere. . That is, when the temperature of the needle valve 25 falls below a predetermined value (for example, the condensation temperature of the atmosphere), the set value of the gas temperature T2 after the first pressure reduction is corrected upward, and the pressure reduction level in the needle valve 25 is relaxed. Good.

  Hereinafter, the function of the controller 40 and a specific setting method of the target pressure reduction level in the controller 40 will be described.

  The controller 40 includes a central processing unit (CPU), and the target value of the secondary pressure of the pressure regulator based on the state quantity of the gas on the primary side of the pressure regulator and the state quantity of the gas on the secondary side of the pressure reducing valve. And a target pressure setting means for determining the pressure reduction profile of the gas, and a pressure adjustment means for adjusting the secondary pressure of the pressure regulator according to the pressure reduction profile. Further, the controller 40 includes gas data acquisition means for acquiring data on the gas state quantity.

  Temperature and pressure may be used as the state quantity of the gas on the primary side of the pressure regulator, and pressure may be used as the state quantity of the gas on the secondary side of the pressure reducing valve. These state quantities correspond to the pressurized and charged state of gas (initial state) and the supply pressure to the user (post-depressurized state), both of which are parameters that can be set by the user at the start of gas supply. In addition, the target value of the secondary pressure of the pressure regulator can also be determined based on the specific enthalpy and density.

  There are roughly two methods for inputting the state quantity of the gas on the primary side of the pressure regulator and the state quantity of the gas on the secondary side of the pressure reducing valve to the controller 40. One is a method in which the user inputs these in advance or during gas supply, and the other is a method in which data acquired by a detection means such as a sensor is taken into the controller 40 via a signal line. In the former case, the controller 40 is provided with gas data input means (not shown) such as a control panel. In the latter case, a temperature sensor or a pressure sensor is provided at the gas container 11, the pipe 12 or the inlet of the pressure regulator. These signal lines may be connected to the controller 40. Further, in the present invention, by providing both the gas data input means and the detection means such as the sensor, the user can input the gas state quantity in advance, and the measured value of the temperature sensor or the pressure sensor during the gas supply. This can be updated automatically as needed.

  In the gas supply device 10 according to the first and second embodiments of the present invention shown in FIG. 1 and FIG. 2, the state quantity (temperature) of the gas on the primary side of the pressure regulator by the temperature sensor 41 a and the pressure sensor 42 a. And pressure). Further, it is assumed that the user supply pressure is used for the state quantity of the gas on the secondary side of the pressure reducing valve, and the user inputs this to the controller 40 via the gas data input means.

Even if the pressure sensor 42a for measuring the pressure of the gas on the primary side of the pressure regulator is installed so as to measure the gas pressure inside the piping on the primary side of the pressure regulator, as shown in FIGS. You may attach directly to the opening-and-closing valve (not shown) of the gas container 11. In general, the volume of the piping on the primary side of the pressure regulator is sufficiently small, and the pressure in the piping and the pressure in the gas container 11 are equivalent and can be converted to each other.
On the other hand, the temperature sensor 41a for measuring the temperature of the high-pressure gas filled in the gas container 11 is installed so as to measure the temperature inside the piping on the primary side of the pressure regulator as shown in FIGS. Alternatively, the atmospheric temperature may be measured. In general, the temperature of the gas from the gas container 11 to the pressure regulator can be regarded as the atmospheric temperature of the gas container 11.

In addition, by providing a weight meter 43 in the gas container 11 and acquiring the remaining amount of the filled gas, the filling pressure of the gas container is calculated based on a predetermined conversion formula, and the primary side of the pressure regulator It can also be transmitted to the gas data acquisition means as gas pressure data.
That is, the gas state quantity data used in the present invention may be set values determined by the user, directly measured by the detection means, or calculated by conversion from other parameters.

Further, the temperature of the secondary side gas of the pressure regulator is measured by the temperature sensor 41b, and the pressure of the gas is measured by the pressure sensor 42b, thereby monitoring whether or not the target pressure reduction profile in the pressure regulator is achieved. It is also suitable. For example, when the pressure reduction profile determined by the target pressure setting means is not accurately realized by adjusting the secondary pressure of the pressure regulator, the secondary pressure is adjusted based on the measured value of the pressure sensor 42b. You should correct it.
Commercially available temperature sensors 41a and 41b and pressure sensors 42a and 42b can be used.

  The controller 40 stores in advance the characteristics of temperature, specific enthalpy and pressure based on the Ph diagram of the gas supplied to the user. From this state, the measured values by the temperature sensor 41a and the pressure sensor 42a and the user supply pressure are input to the controller 40, and further, as a condition for determining the target pressure reduction level, for example, as shown in FIG. The CPU 40 of the controller 40 calculates the target value of the pressure reduction level in the pressure regulator and determines the pressure reduction profile by setting “equalize the temperature (T2, T4) of the gas after the second pressure reduction”. To do. In calculating the target value, a gas Ph diagram may be used, or a calculation may be performed based on a relational expression of the state quantity or physical quantity of the gas.

  The controller 40 adjusts the secondary pressure of the pressure regulator to achieve the target value by the pressure adjusting means. Specifically, when the pressure regulating device is the parallel orifice device 20, one decompression line or a combination of a plurality of decompression lines that can obtain a decompression level closest to the decompression level is selected, and the controller 40 The on / off valves 22a to 22c are closed or opened by the open / close signal. When the pressure regulator is the needle valve 25, the controller 40 obtains the cross-sectional area of the gas flow path that achieves the target value, and adjusts the insertion depth of the needle.

  As described above, in the controller 40, based on the state quantity (for example, temperature and pressure) of the gas on the primary side of the pressure regulator and the state quantity (for example, pressure) of the gas on the secondary side of the pressure reducing valve, Set the target decompression level. When the gas state quantity on the primary side of the pressure regulator changes due to continuous gas supply, or when the supply pressure to the user is changed during gas supply, control is performed at predetermined time intervals or continuously. The target decompression level can be recalculated by the CPU of the device 40 and can be reset so as to always satisfy a predetermined condition such as equalizing the temperature of the gas after decompression in each stage.

In the conventional two-stage pressure reducing valve, it is difficult to adjust and reset the secondary pressure of the first stage pressure reducing valve during gas supply. In this pressure reducing valve, the Joule-Thomson effect of gas becomes excessive, and conversely, when this is set to a low pressure, there is a problem that this becomes excessive in the first pressure reducing valve.
On the other hand, in the gas supply device 10 according to the present invention, when the filling pressure in the gas container is lowered, the target pressure reduction level on the secondary side of the pressure regulating device is lowered in accordance with this, so that Gas supply can be continued while the temperature of the gas passing through the second-stage pressure reducing valve is always kept within a predetermined range.

  Further, in the gas supply device 10 according to the present invention, even if the pressure adjusting device and the pressure reducing valve are temporarily and intensely cooled due to the Joule-Thompson effect in the initial stage of gas supply, The gas temperature can be raised while achieving a balance, and critical condensation or freezing in the pressure regulator or the pressure reducing valve can be avoided.

  Hereinafter, other elements related to the present invention will be described.

The gas used in the present invention is not particularly limited, but is particularly useful when a gas that is used frequently in semiconductor manufacturing equipment or chemical equipment and has a large temperature drop due to the Joule-Thomson effect is used. The effect of the present invention can be remarkably exhibited. Specifically, silane (SiH ₄ ), nitrogen trifluoride (NF ₃ ), silicon fluoride (SiF ₄ ), Freon 14 (CF ₄ ) are examples of compressed gas whose gas container is filled with high-pressure gas. ) Or Freon 116 (C ₂ F ₆ ), and examples of the liquefied gas filled in the gas container include carbon dioxide (CO ₂ ), sulfur hexafluoride (SF ₆ ), or nitrous oxide (N ₂ O) and the like are exemplified.

When compressed gas is used in the present invention, the effect of the present invention is remarkably exhibited when the compression coefficient (z) of the gas in the filled state in the gas container is less than 1.0, particularly 0.7 or less.
Here, the critical state of a substance refers to the temperature and pressure states at which the gas and liquid can coexist. The temperature in the critical state is referred to as critical temperature (Tc [K]), and the pressure in the critical state is referred to as critical pressure (Pc [MPa]). The critical temperature means a temperature at which the gas is not liquefied when the temperature is exceeded, regardless of the degree of compression. On the other hand, the critical temperature Tr is obtained by dividing the gas temperature [K] in a certain state by the critical temperature Tc [K]. Similarly, the countercritical pressure Pr is the gas pressure [MPa in a certain state. ] Is divided by the critical pressure Pc [MPa].
The reason why the compression coefficient z is preferably in the above numerical range will be described below.

In general, according to Lee and Kesler's modified Benedict-Webb-Rubin (BWR) equation of state, the gas compression coefficient z () is calculated from the eccentricity ω determined from the molecular shape of the gas, the critical temperature Tr, and the critical pressure Pr. = PV / RT) is known, and industrially, the compression coefficient z is determined using the z diagram from the critical temperature Tr and the critical pressure Pr regardless of the type of gas. Can do.
The compression coefficient z is the volume ratio between the real gas and the ideal gas having the same number of moles at the same temperature and pressure, and if this is small, it means that the volume of the gas becomes smaller in a state compressed to a high pressure. Dimensional quantity.

In an ideal gas, the compression coefficient z is always 1, and the remaining amount of gas in the gas container and the gas filling pressure are in a proportional relationship. However, in an actual gas, the compression coefficient z varies with the critical pressure Pr. The compressed gas filled at a high pressure in the gas container has a critical temperature Tr of 1.0 to 1.5 and a critical pressure Pr of about 1.0 to 3.0. In this state, the compression coefficient z is 1. Less than. In this state, the compression coefficient z gradually approaches 1.0 as the gas is derived from the gas container.
Therefore, when the ideal gas is continuously supplied from the gas container to the user, when the filling weight in the gas container decreases, the pressure of the gas introduced into the pressure reducing valve decreases in proportion to this, but in supplying the actual gas, In a gas state in which the compression coefficient z increases with a decrease in the critical pressure Pr, the gas volume is increased against the decrease in the filling weight of the gas. The pressure of is not reduced easily. That is, when the real gas filled with high pressure is continuously supplied, the high pressure gas continues to flow into the first stage pressure reducing valve for a long time, and cooling of the pressure reducing valve by the Joule-Thomson effect continues for a long time. .

  Therefore, when the compression coefficient z of the gas filled in the gas container at the start of the gas supply or during the supply is less than 1.0, particularly 0.7 or less, the compression coefficient z becomes 1 as the gas filling amount decreases. Since the pressure rises asymptotically to 0.0, the temperature drop of the pressure reducing valve becomes significant. Therefore, in such a case, it is possible to sufficiently enjoy the effect of the present invention in which the target pressure reduction level in each stage of the multistage pressure reducing valve is set to balance the temperature drop. In the case of a gas filling state in which the gas compression coefficient z is 0.7 or less and the critical temperature Tr is 1.3 or less, the increase in the compression coefficient z accompanying the decrease in the gas filling amount becomes more remarkable. The effects of the invention are most preferably enjoyed. Note that the compression coefficient z and the Joule-Thomson coefficient μ are both parameters representing the degree of the actual gas effect, and the compression coefficient z greatly deviates from 1.0 representing the ideal gas and becomes 0.7 or less. In general, since the Joule-Thomson coefficient μ also takes a large absolute value, the temperature drop of the pressure reducing valve becomes significant when the compressed gas is supplied under reduced pressure.

  Further, the present invention aims to balance the temperature of the pressure regulator and the pressure reducing valve cooled by the Joule-Thomson effect of gas, and to prevent condensation and freezing of water vapor in the atmosphere. In particular, when the Joule-Thomson coefficient μ of the gas filled in is not less than +4 [K / MPa], the effect of the present invention can be fully enjoyed. The Joule-Thomson coefficient of the gas can be obtained from the interval and gradient of the isothermal line in the Ph diagram and a known conversion formula.

  Table 1 shows the general filling state in the gas container and the pressure and temperature in the critical state for typical compressed gas suitably used in the present invention. In a predetermined filling state in the gas container, those skilled in the art can naturally obtain the gas compression coefficient z from the z diagram and the Joule-Thomson coefficient μ from the Ph diagram, respectively.

  Since the compression coefficient z in the gas filling state shown in Table 1 is 0.7 or less and the critical temperature Tr is 1.3 or less, stable and continuous by the gas supply method according to the present invention. High effect of gas supply is demonstrated.

Hereinafter, other components that can be used in the present invention will be described.
A commercially available gas cylinder can be used for the gas container 11. A material that can withstand an internal pressure of several MPa to several tens of MPa and that does not corrode by the stored gas is preferable.

  The pipe 12 is not particularly limited as long as the gas container 11 and the gas use facility are connected to each other and the high-pressure gas can be reduced in multiple stages and supplied to the user. A metal tube is preferably used because of its corrosion resistance and good heat transfer efficiency with the atmosphere.

  The pressure reducing valve 30 connects the primary side to a high pressure regulator and connects the secondary side to a low pressure user side. As long as it has the function of depressurizing the high-pressure gas on the primary side and discharging it to the secondary side, the operating principle is not limited in addition to the type in which a movable sheet or diaphragm is balanced and held by a spring. Absent. Further, as in the above embodiment, when the gas supply pressure to the user is constant (P4 = 0.45 MPa), the secondary pressure of the pressure reducing valve 30 may be fixed to the supply pressure. In addition, when the supply pressure to the user is increased or decreased during the supply of gas, the pressure regulator 30 such as the needle valve 25 used as the pressure regulator in the second embodiment is used as the pressure reducing valve 30, and the controller 40 The secondary pressure may be adjusted with time.

  As shown in FIG. 2, a buffer tank 13 may be provided between the pressure regulator and the pressure reducing valve 30 in the pipe 12. By temporarily storing the gas decompressed by the pressure regulator in the buffer tank 13 and then sending it to the pressure reducing valve 30, it is possible to suppress the pressure fluctuation of the gas supplied to the user and to reduce the temperature by reducing the pressure by the pressure regulator. It is possible to sufficiently recover the temperature of the lowered gas in a normal temperature atmosphere. As the buffer tank 13, a container communicating with the pipe 12 can be used, or the pipe 12 may be partially expanded in diameter.

  Further, for the purpose of performing the temperature recovery more sufficiently, a heater 14 such as a ribbon heater or a hot water tube may be supplementarily provided as a heating means between the pressure regulator and the pressure reducing valve 30. In this case, although it is necessary to use an external utility such as electric power or hot water, for example, when the ambient temperature is low, or when the gas supply amount is large and the cooling speed of the pressure regulator or the pressure reducing valve 30 is extremely fast, By supplementarily heating the gas, the gas can be supplied more stably and over a long period of time. According to the present invention, even if a heating means is used, an advantage is obtained that the thermal energy to be given by electric power or hot water can be greatly saved as compared with the conventional gas supply device. The heater 14 may be attached to the buffer tank 13 or may be attached to a portion of the pipe 12 between the pressure regulator and the pressure reducing valve 30.

The weigh scale 43 provided in the gas container 11 transmits weight data regarding the amount of remaining gas to the controller 40 at predetermined time intervals. That is, the weigh scale 43 functions as a remaining gas amount detecting means for acquiring remaining amount data of the gas filled in the gas container. In particular, for highly compressible gases such as silane (SiH ₄ ) and nitrogen trifluoride (NF ₃ ), the pressure in the gas container and the remaining amount of the gas are in a predetermined correspondence relationship. The pressure sensor 42a provided on the primary side can be used as a gas remaining amount detecting means, and the remaining gas amount can be measured from the read value. As for the correspondence relationship between the primary pressure of the pressure regulator and the remaining gas amount (weight), a converted value may be input to the controller 40 in advance. The weighing scale 43 can be a commercially available digital weighing scale having a data logger function.

  Further, the controller 40 estimates the supply amount of the gas flowing through the gas line according to the fluctuation amount per unit time of the measurement value of the weight scales 43a to 43c or the pressure sensors 42a1 to 42a3 which are the gas remaining amount detection means. When the predetermined value is exceeded, the target pressure reduction level in the pressure regulator may be reset. In particular, when the heat transfer efficiency with the heat capacity or atmosphere of the pressure regulator and those of the pressure reducing valve 30 are greatly different from each other, the cooling rate of the two changes due to fluctuations in the flow rate of the supply gas. Is preferably reset.

The gas supply method using the gas supply apparatus according to the present invention will be described more specifically with reference to examples. The system diagram of the gas supply device 10 is according to the second embodiment (FIG. 2), and a needle valve 25 is used as the pressure regulator. FIG. 4 shows a Ph diagram of NF ₃ gas and a decompression profile according to this example using the gas. In the present embodiment, the pressure reduction (states a1 to a4: solid line) in the fully filled state (P1 = 10.8 MPa) of the gas container, the state where the remaining amount of gas filled in the gas container is about 70% (P1). '= 7.02 MPa) under reduced pressure (states b1 to b4: broken lines), under reduced pressure with the remaining amount of the filled gas being about 37% (P1 ″ = 4.0 MPa) (States c1 to c2: one-dot chain line) Note that the ambient temperature in this embodiment is 30 ° C., and the gas decompressed by the needle valve 25 reaches the decompression valve 30 after recovering to the ambient temperature. And

  The decompression profile in the full filling state is the same as that shown in FIG. 3, and the target decompression level in the first stage is 5.4 MPa (= P2). By adjusting the needle depth of the needle valve 25 and adjusting the secondary side pressure to such a reduced pressure level, the gas temperature after the first-stage decompression (T2) and the gas temperature after the second-stage decompression (T4) Can be made equal. That is, when the pressure reduction profile is adopted, the temperature drop width of the gas is most suppressed.

In this embodiment using NF ₃ gas, the temperature of the gas after depressurization at each stage is about 2 ° C. When a gas of 2 ° C flows through a needle valve or pressure reducing valve having general thermal conductivity and heat capacity placed in a normal temperature atmosphere, the surface has a thermal equilibrium temperature of 11 ° C (20 ° C, air with a relative humidity of 50%) Is a gas flow rate of 4.5 [L / min]. On the other hand, in the case of decompression by the conventional two-stage decompression valve whose decompression profile is shown in FIG. 6, since the temperature of the gas after decompression of the first stage is −25 ° C., the thermal equilibrium temperature of the valve surface is similarly 11 ° C. In order to maintain this, it is necessary to suppress the gas flow rate to 1.3 [L / min] or less.
That is, according to the gas supply method and the gas supply apparatus that realizes the gas supply according to the present embodiment, it is possible to continuously supply a gas having a flow rate that is three times that of the conventional method.

In addition, when silane (SiH ₄ ) is used as the user-supplied gas, and the two-stage decompression is similarly performed using the decompression profile that equalizes the temperature of the decompressed gas in each stage, the temperature of the decompressed gas is about 0.8. It becomes ℃. In this case, if the gas flow rate is about 10.0 [L / min], it is possible to maintain the thermal equilibrium temperature of the surface of the needle valve or pressure reducing valve in a room temperature atmosphere at 11 ° C.
Similarly, when argon gas is used as the user-supplied gas, the temperature of the gas after decompression is 15 ° C., so that the thermal equilibrium temperature of the valve surface can be maintained at 11 ° C. regardless of the flow rate.

  In the decompression profiles b1 to b4 where the initial pressure is P1 ′, the gas temperature (T2 ′) after the first decompression and the gas temperature (T4 ′) after the decompression after the second decompression are made equal. From the Ph diagram, it can be seen that the target pressure reduction level in the first stage may be set to 3.9 MPa (= P2 ′).

  Further, in the decompression profiles c1 to c2 with the initial pressure P ″, the gas is decompressed only by the decompression valve 30 without performing the first decompression by the needle valve 25, that is, without restricting the flow path by the needle. Also in this case, since the initial pressure is as low as 4.0 MPa, a sufficient temperature of about 16 ° C. is maintained even at the gas temperature after decompression (T2 ″).

  In the subsequent gas supply, since the initial pressure further decreases from 4.0 MPa, the pressure is reduced to a predetermined supply pressure (P3) only by the pressure reducing valve 30 without being reduced by the needle valve 25 and supplied to the user. be able to. Such gas supply can be continuously performed as long as the pressure on the primary side of the pressure reducing valve 30 exceeds the pressure on the secondary side, that is, until the filling pressure of the gas container 11 reaches 0.5 MPa (= P3).

FIG. 2 is a system diagram of the gas supply device 10 in which three gas lines whose system diagram is shown are arranged in parallel, and the on / off valves 44a to 44c provided in each gas line are opened and closed by the controller 40 to switch the gas flow path. Is shown in FIG. In the gas lines 1 to 3, gas containers 11a to 11c, their weigh scales 43a to 43c, needle valves 25a to 25c, pressure reducing valves 30a to 30c, pressure sensors 42a1 to 42a1 for measuring the pressure of the gas filled in the gas containers, respectively. 42a3, temperature sensors 41a1 to 41a3 that measure the temperature, pressure sensors 42b1 to 42b3 that measure the secondary pressure of the needle valve, and temperature sensors 41b1 to 41b3 that measure the surface temperature of the needle valve.
Further, a user-supplied gas pressure regulating valve 50 is provided downstream of the merging portion of the gas lines 1 to 3. That is, the gas derived from the gas containers 11a to 11c is decompressed in three stages and supplied to the user. Thereby, pressure reduction in each stage can be performed more gently, and the temperature drop of the gas due to the Joule-Thompson effect can be reduced. Two or more user-supplied gas pressure regulating valves 50 may be provided in series downstream of the merging portions of the gas lines 1 to 3, and the gas supply lines 1 to 3 may be connected to the secondary side of the pressure reducing valves 30 a to 30 c. Two or more may be provided in series, or one or two or more may be provided on the upstream side and the downstream side of the junction.

  In the controller 40, the gas pressure in each gas line is such that the temperature of the gas after the first stage depressurization by the needle valves 25a to 25c is equal to the temperature of the gas after the second stage depressurization by the pressure reducing valves 30a to 30c. The secondary pressure of the needle valves 25a to 25c is adjusted so that Further, in the controller 40, the temperature of a portion exemplified by the surface temperature of the needle valve, the surface temperature of the pressure reducing valve, or the temperature of the gas after the first pressure reduction in the gas line supplying the gas is a predetermined value (for example, the atmosphere When the dew condensation temperature is reached, control is performed to switch the gas flow path by closing or opening the on-off valves 44a to 44c. The on-off valves 44a to 44c connected to the controller 40 have a function as an automatic closing valve and can close any or all gas lines in response to a stop signal from the controller 40. Thereby, for example, even when the gas supply device 10 is stopped urgently because the flow rate of the supply gas exceeds a predetermined value, it can be quickly and safely stopped.

  Further, the controller 40 estimates the supply amount of the gas flowing through the gas line according to the fluctuation amount per unit time of the measurement value of the weight scales 43a to 43c or the pressure sensors 42a1 to 42a3 which are the gas remaining amount detection means. Even when a predetermined value is exceeded, control is performed to switch the gas flow path by opening and closing the on-off valves 44a to 44c as appropriate.

  When a gas line that is supplying gas is closed and any of the gas lines that have been stopped is selected and opened, the gas line to be selected can be determined based on a predetermined condition. For example, the gas line with the highest temperature of the needle valve or the pressure reducing valve, the gas line with the highest or lowest gas filling amount in the gas container, or the oldest gas container installed in the gas supply device is provided. A gas line or the like may be preferentially selected.

  By performing such control, in the gas supply device 10 according to the present embodiment, the gas having a high Joule-Thomson coefficient while maintaining the temperatures of the needle valves 25a to 25c and the pressure reducing valves 30a to 30c sufficiently high according to the atmospheric temperature. Can be stably and continuously supplied at a large flow rate. In addition, by providing a plurality of gas containers, the gas supply to the user is not stopped even when one of the gas containers becomes empty and needs to be replaced.

  The gas that is suitably decompressed and supplied by the gas supply method and the gas supply apparatus according to the present invention includes the process gas and etching gas of the semiconductor manufacturing apparatus and chemical apparatus, and the material gas for various manufacturing apparatuses and experimental apparatuses. The reaction gas or the purge gas can be targeted and can be used in a wide range.

It is a systematic diagram of the gas supply apparatus concerning 1st embodiment of this invention. It is a systematic diagram of the gas supply apparatus concerning 2nd embodiment of this invention. And P-h diagram of the NF ₃ gas, a vacuum profile of an embodiment of the present invention. It is a decompression profile concerning the 1st example of the present invention. It is a systematic diagram of the gas supply apparatus concerning the 2nd Example of this invention. It is a pressure reduction profile in the conventional two-stage pressure reducing valve.

Explanation of symbols

1, 2, 3 Gas line 10 Gas supply device 11 Gas container 12 Pipe 13 Buffer tank 14 Heater 20 Parallel orifice device 21a, 21b, 21c Decompression line 22a, 22b, 22c On-off valve 23a, 23b, 23c Orifice 25 Needle valve 30 Depressurization Valve 40 Controller 41a, 41b Temperature sensor 42a, 42b Pressure sensor 43 Weigh scale 44a, 44b, 44c Open / close valve 50 User supplied gas pressure regulating valve

Claims (12)

A gas container filled with gas under pressure;
Piping for circulating the gas derived from the gas container;
A pressure regulator that is provided in the pipe, introduces the flowing gas from the primary side, and further reduces the pressure so that the pressure can be adjusted, and discharges the gas from the secondary side;
A pressure reducing valve that is provided on the secondary side of the pressure regulator and depressurizes the circulating gas;
Gas data acquisition means for acquiring data on the primary gas state quantity and the secondary gas state quantity data of the pressure reducing valve, respectively, and the adjustment based on the acquired gas state quantity data. A controller comprising target pressure setting means for determining a target value of the secondary pressure of the pressure device, and pressure adjusting means for adjusting the secondary pressure of the pressure regulator in accordance with the target value;
A gas supply device. The state quantity of the gas on the primary side of the pressure regulator is the pressure of the gas measured by a pressure sensor provided in the gas supply device, and the ambient temperature input by the gas data input means provided in the controller ,And,
The gas supply device according to claim 1, wherein the state quantity of the gas on the secondary side of the pressure reducing valve is a user supply pressure input by the gas data input means. A pressure adjusting device, a plurality of pressure reducing lines each provided with a plurality of orifices having different diameters in parallel; and a switching means that is driven by the pressure adjusting means to switch a gas flow path to one or more of the plurality of pressure reducing lines; The gas supply device according to claim 1, comprising: The pressure regulator is a needle valve that inserts a needle into the flow path of the flowing gas, and
The gas supply device according to claim 1 or 2, wherein the insertion depth of the needle can be continuously adjusted by the pressure adjusting means. The gas supply device according to claim 4, further comprising a temperature sensor that measures the temperature of the needle valve. The gas supply device according to any one of claims 1 to 5, further comprising a temperature sensor that measures a temperature of a gas on a secondary side of the pressure regulator, or a pressure sensor that measures a pressure of the gas. A gas supply method for supplying gas to a user by depressurizing a gas filled in a gas container in multiple stages,
Based on the state quantity of the gas pressurized and filled in the gas container and the state quantity of the gas decompressed in multiple stages, a target decompression level of the gas in the middle stage is set, and according to the target decompression level A gas supply method characterized by depressurizing the gas. The state quantity of the gas pressure-filled in the gas container is the temperature and pressure of the gas,
The gas supply method according to claim 7, wherein the state quantity of the gas decompressed in multiple stages is the pressure of the gas. The target decompression level of the gas is
The gas supply method according to claim 7 or 8, wherein both the temperature of the gas decompressed in multiple stages and the temperature of the gas in the middle stage are set to a predetermined temperature or higher. The target decompression level of the gas is
The gas supply method according to any one of claims 7 to 9, wherein the temperature of the gas decompressed in multiple stages is made equal to the temperature of the gas in the intermediate stage. The gas decompression is performed according to the reset target decompression level after resetting the target decompression level of the gas in the middle stage when the filling pressure in the gas container decreases. The gas supply method according to any one of 7 to 10. The temperature or pressure of the gas decompressed in one stage or multiple stages is measured, and when the temperature or pressure reaches a predetermined value, the target decompression level of the gas in the intermediate stage is reset, and the reset is performed. The gas supply method according to any one of claims 7 to 11, wherein the gas is depressurized at an intermediate stage according to the target depressurization level.

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