JP5583437B2 - Vacuum environment test equipment - Google Patents

Description

  The present invention relates to a vacuum environment test apparatus for testing various devices used in a vacuum environment.

The conventional vacuum environment apparatus is intended to evacuate the inside of the vacuum vessel with various vacuum pumps, absorb outgas emitted from a specimen stored in the vacuum vessel, and assist the vacuum pump. The inside of the vacuum vessel is configured to be a high vacuum by the contamination panel. For various gases that are outgasses, the relationship between the ultimate vacuum and the condensable panel temperature is determined by the low temperature vapor pressure curve, and trace gases in the cryogenic region below 20K are exhausted by a high vacuum exhaust pump such as a cryopump. Gas in the region of 100K or less such as H ₂ O is absorbed and exhausted by the contamination panel. Liquid nitrogen is generally used as a cold source for the contamination panel. Since the amount of liquid nitrogen consumed is proportional to the amount of heat transfer between the contamination panel surface and other internal devices, it is difficult to reduce the amount of nitrogen consumed.

  As a conventional technique related to such a contamination panel, in Japanese Patent Laid-Open No. 5-65100, in a space environment test apparatus provided with a contamination panel inside a vacuum vessel that houses the specimen, the specimen and the contamination are included. An example in which a shield for a contamination panel is detachably provided between the panels is disclosed. According to this prior art, by mounting the shield plate, while preventing the heat release of the specimen during shroud normal temperature return and specimen withering operation, the heat transfer with the temperature adjustment shroud is limited, It is described that the amount of liquid nitrogen for contamination and nitrogen gas for temperature adjustment can be reduced.

JP-A-5-65100

  However, since this conventional technique temporarily cuts off the radiant heat of the specimen by means of the shield plate to reduce the nitrogen consumption, the shroud is returned to room temperature as described in the literature, and the specimen is exhausted for a short time. This is expected to be effective, but is not a drastic measure for reducing liquid nitrogen consumption during testing with higher amounts of liquid nitrogen.

  The objective of this invention is providing the vacuum environment apparatus which can reduce the liquid nitrogen consumption of the vacuum apparatus provided with the contamination panel effectively.

In order to achieve the above object, the present invention provides a vacuum environment test apparatus equipped with a contamination panel inside a vacuum vessel containing a specimen, and a high vacuum pump for evacuating the vacuum vessel.
The above contamination panel is composed of independent gas phase panel and liquid phase panel,
Means for supplying liquid nitrogen;
A gas-liquid separation means for separating the supplied nitrogen into a gas phase and a liquid phase;
Means for supplying separated vapor and liquid phase nitrogen to the independent vapor and liquid phase panels, respectively;
A means for releasing the gasified high temperature nitrogen gas into the atmosphere by raising the temperature in each of the above contamination panels;
The contamination panel is cooled by latent heat of liquid nitrogen by the liquid phase panel and sensible heat of nitrogen gas by the gas phase panel.

Further, in the vacuum environment test apparatus described above, the contamination panel is arranged such that the liquid phase panel is disposed below and the gas phase panel is disposed above, so that the upper portion becomes high as a whole. It is structured . Further, in the vacuum environment test apparatus described above, the liquid phase panel is arranged vertically so that liquid nitrogen is introduced from below the liquid phase panel and led out from above, and the gas phase panel is It is characterized in that it is disposed horizontally above the liquid phase panel . In the vacuum environment test apparatus described above, the contamination panel to which liquid nitrogen is supplied is composed of a plurality of parallel panels connected in parallel, and the inlet and outlet of each parallel panel are connected by an inlet header and an outlet header, respectively. It is characterized by being.

  According to the vacuum environment apparatus of the present invention, liquid nitrogen consumption can be more efficiently reduced without impairing the outgas absorption and exhaust performance of the contamination panel.

It is the figure which modeled the vacuum environment apparatus of Example 1 of this invention. It is the figure which showed an example of the evacuation characteristic of this invention. It is the figure which modeled the contamination panel of Example 2 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic view of a vacuum environment apparatus according to an embodiment of the present invention, wherein 1 is a vacuum vessel, 2 is a specimen stored in the vacuum vessel 1, and 3 is a roughing vacuum for bringing the inside of the vacuum vessel 1 into a low vacuum state. It is a vacuum pump. Generally, the roughing vacuum pump 3 refers to a combination of an oil rotary vacuum pump and an oil diffusion pump or a mechanical booster pump. The low vacuum state is from atmospheric pressure to about 0.1 Pa. Reference numeral 4 denotes a high vacuum pump that changes the inside of the vacuum vessel 1 from a low vacuum state to a high vacuum state. In general, a high vacuum pump refers to a turbo molecular pump, a cryosorption pump, or a combination of both, and a high vacuum state is a state of about 0.1 Pa or less.

  5 (5 a 1, 5 a 2, 5 b) absorbs outgas emitted from the specimen 2 and the like housed in the vacuum vessel 1 by being cooled with liquid nitrogen and gaseous nitrogen, and the high vacuum pump 4 5a1, 5a2 are liquid phase panels in which liquid nitrogen (liquid phase) flows as a medium, and 5b is a low-temperature nitrogen gas containing liquid nitrogen mist (such as liquid nitrogen mist). It is a gas phase panel in which gaseous nitrogen) flows as a medium. Both panels have an independent configuration, the liquid phase panels 5a1, 5a2 are arranged vertically, and the gas phase panel 5b is arranged horizontally above the liquid phase panel.

  6 is a liquid nitrogen storage tank as means for supplying liquid nitrogen, 7 is a gas-liquid separation cylinder (gas-liquid separation means) for separating nitrogen supplied from the liquid nitrogen storage tank 6 into a gas phase and a liquid phase, and 7a and 7b are respectively , A pipe as means for supplying liquid nitrogen and gaseous nitrogen to the liquid phase panels 5a1, 5a2 and the gas phase panel 5b; 8 is a high temperature nitrogen gas which is gasified by increasing the temperature inside the contamination panel 5; It is a diffusion tower as a means to release to the atmosphere.

  The liquid phase panels 5a1 and 5a2 are arranged side by side in a state of being placed vertically, and liquid nitrogen is introduced from below the panel 5a1 disposed on the high vacuum pump 4 side via a pipe 7a. Derived from above, further introduced from below the panel 5a2, led out from above, and led to the diffusion tower 8. Accordingly, each liquid phase panel has a low temperature at the bottom and a high temperature at the top. As described above, the gas phase panel 5b is disposed on the upper side and the liquid phase panel 5a is disposed on the lower side. Further, as described above, the upper side of the liquid phase panel 5a is set at a higher temperature so that the contamination panel 5 as a whole is upper. Is kept at a high temperature to prevent the stored specimen 2 from being cooled.

  Further, 9 is a high-pressure supply valve for controlling the supply amount of high-pressure liquid nitrogen in the liquid nitrogen storage tank 6, 10 is a low-pressure supply valve for controlling the supply amount of low-pressure liquid nitrogen in the gas-liquid separation cylinder 7, and 11 is a gas-liquid separation cylinder 7. A liquid level gauge for indicating the liquid level of the liquid container, 12 is a thermometer for measuring the temperature of the liquid phase panel 5a2 on the high temperature side of the contamination panel 5a, 13 is a vacuum gauge for measuring the degree of vacuum of the vacuum vessel 1, and 14 is a liquid level. The control device controls the opening degree of the high-pressure supply valve 9 and the low-pressure supply valve 10 with the total 11, the thermometer 12 and the vacuum gauge 13 as inputs.

  The operation method of the present invention will be described below. The inside of the vacuum vessel 1 equipped with the specimen 2 is first brought to a low vacuum state by the roughing vacuum pump 3. Next, the roughing vacuum pump 3 and the high vacuum pump 4 are switched, and gas and liquid nitrogen are supplied to the contamination panel 5 to bring the inside of the vacuum vessel 1 into a high vacuum state. An example of the vacuum evacuation characteristics is shown in FIG. 2, and starts in the order of rough vacuum pump 3, turbo molecular pump (high vacuum pump 4), contamination panel 5, cryosorption pump (high vacuum pump 4) in this order (vacuum) The vacuum vessel 1 is brought into a high vacuum state.

  A basic expression for calculating the exhaust in the vacuum vessel 1 is expressed by (Expression 1).

ここで、Ｖは被排気容量、Ｐは圧力、Ｓ_ｅは有効排気速度、Ｑ（ｔ）はアウトガス量である。コンタミネーションパネル５は上式のＱ（ｔ）成分を吸収し、クライオソープションポンプの負荷を軽減させる役割を有する。

Here, V is an exhausted capacity, P is a pressure, _Se is an effective exhaust speed, and Q (t) is an outgas amount. The contamination panel 5 has the role of absorbing the Q (t) component of the above formula and reducing the load on the cryosorption pump.

In the operation method of the contamination panel 5, first, liquid nitrogen is supplied from the liquid nitrogen storage tank 6 under high pressure to the gas-liquid separation cylinder 7 via the high pressure supply valve 9. The supply amount at this time is controlled so that the high pressure supply valve 9 is controlled by the control device 14 with the signal of the liquid level gauge 11 installed in the gas-liquid separation cylinder 7 as an input, and the signal of the liquid level gauge 11 falls within a predetermined range. The liquid level of the liquid separation cylinder 7 is controlled. A part of the high-pressure liquid nitrogen supplied to the gas-liquid separation cylinder 7 becomes flash gas in the gas-liquid separation cylinder 7 which is under substantially atmospheric pressure. Here, if the saturated liquid enthalpy in the liquid nitrogen storage tank 6 is h _LCE , the saturated liquid enthalpy in the gas-liquid separation cylinder 7 is h _LT , and the saturated gas enthalpy is h _VT , the liquefaction amount h _L and the total latent heat H _fg are expressed by 2).

気液分離筒７で分離された液相の液体窒素は、配管７ａと低圧供給弁１０を介して、コンタミネーションパネル５ａの下部から供給され、パネル内を上方に向かい流通し、上部から窒素ガスとして排出される。この際の供給量はコンタミネーションパネル５ａの上方に設置された温度計１２、及び真空容器１に設置された真空計１３の信号を入力として、制御装置１４により低圧供給弁１０を制御し、温度計１２及び真空計１３の信号が所定範囲になるようにする。

The liquid phase liquid nitrogen separated in the gas-liquid separation cylinder 7 is supplied from the lower part of the contamination panel 5a through the pipe 7a and the low pressure supply valve 10, flows upward in the panel, and nitrogen gas from the upper part. As discharged. The supply amount at this time is controlled by controlling the low-pressure supply valve 10 by the control device 14 using the signals of the thermometer 12 installed above the contamination panel 5a and the vacuum gauge 13 installed in the vacuum vessel 1 as input. The signals of the gauge 12 and the vacuum gauge 13 are set within a predetermined range.

  On the other hand, the low-temperature nitrogen gas in the vapor phase separated by the gas-liquid separation cylinder 7 flows into the contamination gas-phase panel 5b via the pipe 7b due to the pressure difference between the gas-liquid separation cylinder 7 and the atmospheric pressure. Via this, it is mixed and mixed with the nitrogen gas of the liquid phase panel 5 a of the contamination panel, and is released into the atmosphere by the diffusion tower 8.

Here, when the nitrogen consumption consumed by the contamination panel 5a and F _NC, the amount of liquid nitrogen loss by flash gas (flash loss amount) F _Loss is (Equation 3).

また、コンタミネーションパネル５ａの伝熱面積Ａは（式４）で概算できる。

Further, the heat transfer area A of the contamination panel 5a can be estimated by (Equation 4).

但し、Ｑはコンタミネーションパネル５ａが必要とする伝熱量、αは輻射伝熱量とパネル面への凝縮確率の積を温度差で除した等価熱伝達率、ΔＴは温度差（雰囲気温度−パネル温度）である。さらに、前述したコンタミネーションパネル５ａで消費される窒素消費量Ｆ_ＮＣは前記Ｑを窒素の温度変化に相当するエンタルピ落差Ｊで除すことで概算できる。

Where Q is the amount of heat transfer required by the contamination panel 5a, α is the equivalent heat transfer coefficient obtained by dividing the product of the radiation heat transfer amount and the probability of condensation on the panel surface by the temperature difference, and ΔT is the temperature difference (atmosphere temperature−panel temperature). ). In addition, the nitrogen consumption F _NC consumed by contamination panel 5a described above can be approximated by dividing the enthalpy drop J corresponding to the Q to a temperature change of the nitrogen.

  Since the liquid phase panel is introduced from the lower side and led out from the upper side, the lower side has a low temperature and the upper side has a high temperature. This serves to prevent the specimen 2 from being cooled as described above. . Further, the panel 5a1 has a temperature lower than that of the panel 5a2, the absorption capacity on the surface is increased, and the burden on the high vacuum pump 4 is reduced.

  According to this embodiment, even when there is a change in outgas due to the exposure time of the specimen 2 or the inner surface of the vacuum vessel 1 due to the test interval, a high vacuum can be maintained by controlling the contamination panel 5, and the nitrogen consumption can be reduced. It can be optimized. In addition, since most of the outgas components are moisture, controlling the panel temperature at about 150K effectively uses nitrogen by using both the latent heat of liquid nitrogen by the panel 5a and the sensible heat of nitrogen gas by the panel 5b. As a result, the nitrogen consumption can be reduced.

  In addition, when the liquid nitrogen storage tank 6 is the exclusive organic of this apparatus, by reducing the supply pressure freely, it is possible to suppress the amount of flash gas and supply liquid nitrogen to the panel to increase the absorption efficiency. In the case of a shared machine used for other facilities, the pressure adjustment becomes dependent on other facilities, and high pressure operation may be forced. Also in this case, the sensible heat in the vapor phase for the flash gas can be consumed by the vapor phase panel 5b of the contamination panel, so that nitrogen can be consumed efficiently.

  A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic view showing an example of the contamination panel according to the present invention.

  The difference from the first embodiment is that the contamination panel 5a includes a plurality of panels 50 to 53 and a plurality of headers 500 to 503, and other configurations, operations and effects are the same as those of the first embodiment.

  The panels 50 and 51 constitute a plurality of parallel panels that are connected in parallel. The inlet of each parallel panel is connected by an inlet header 500, and the outlet is connected by an outlet header 501. The header 500 is connected to an inlet at a lower position of the panels 50 and 51, and the header 501 is connected to an outlet at an upper position of the panels 50 and 51. This is the same for the panels 52 and 53 and the headers 502 and 503. The headers 501 and 502 are connected by piping so as to communicate with each other. As a whole, the parallel panels of the panels 50 and 51 and the parallel panels of the panels 52 and 53 are connected in series.

  As an effect peculiar to the present embodiment, since the number of panels increases and the surface area increases, the latent heat and sensible heat necessary for outgas absorption can be efficiently utilized, and the flow path of nitrogen becomes longer, so the nitrogen temperature is set to room temperature. Since it can be recovered to the vicinity and discharged to the stripping tower, the nitrogen consumption can be further optimized. In addition, since the control of the effective heat transfer surface can be widened by controlling the amount of nitrogen, it is possible to cope with a wide range of fluctuations in outgas.

  DESCRIPTION OF SYMBOLS 1 ... Vacuum container, 2 ... Specimen, 3 ... Rough vacuum pump, 4 ... High vacuum pump, 5 ... Contamination panel, 5a, 5a1, 5a2 ... Liquid phase panel, 5b ... Gas phase panel, 6 ... Liquid nitrogen storage tank (Means for supplying liquid nitrogen), 7 ... Gas-liquid separation cylinder (gas-liquid separation means), 7a, 7b ... Means for supplying nitrogen, 8 ... Stripping tower (means for releasing nitrogen gas to the atmosphere), 9 ... High pressure Supply valve, 10 ... Low pressure supply valve, 11 ... Liquid level gauge, 12 ... Thermometer, 13 ... Vacuum gauge, 14 ... Control device, 50 Han 3 ... Parallel panel, 500, 502 ... Inlet header, 501, 503 ... Outlet header .

Claims (4)

In a vacuum environment test apparatus equipped with a contamination panel inside a vacuum container for storing a specimen and a high vacuum pump for evacuating the inside of the vacuum container,
The above contamination panel is composed of independent gas phase panel and liquid phase panel,
Means for supplying liquid nitrogen;
A gas-liquid separation means for separating the supplied nitrogen into a gas phase and a liquid phase;
Means for supplying separated vapor and liquid phase nitrogen to the independent vapor and liquid phase panels, respectively;
A means for releasing the gasified high temperature nitrogen gas into the atmosphere by raising the temperature in each of the above contamination panels;
A vacuum environment test apparatus configured to cool the contamination panel by latent heat of liquid nitrogen by the liquid phase panel and sensible heat of nitrogen gas by the gas phase panel.   2. The vacuum environment test apparatus according to claim 1, wherein the contamination panel is arranged such that the liquid phase panel is disposed below and the gas phase panel is disposed above, so that the upper portion becomes high as a whole. A vacuum environment testing apparatus characterized by being configured.   3. The vacuum environment test apparatus according to claim 2, wherein the liquid phase panel is arranged in a vertical direction so as to introduce liquid nitrogen from below the liquid phase panel and lead out from above. A vacuum environment test apparatus, which is disposed horizontally above a liquid phase panel.   The vacuum environment test apparatus according to any one of claims 1 to 3, wherein a plurality of contamination panels to which liquid phase nitrogen is supplied are formed of parallel panels connected in parallel, and an inlet and an outlet of each parallel panel are respectively inlet headers. And a vacuum environment tester characterized by being connected by an outlet header.

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