JP4418722B2 - Barometric pressure control device for absolute pressure control room - Google Patents

Description

  The present invention relates to an atmospheric pressure control device for an absolute pressure control chamber for using a precision processing machine equipped with a device that is easily affected by atmospheric pressure fluctuation such as an optical length measuring device.

  Optical length measuring devices used in the field of microfabrication industries such as the semiconductor industry are easily affected by the surrounding atmospheric pressure, and when the atmospheric pressure changes, a length measurement error occurs, which makes precise processing difficult. For this reason, it is desirable that the optical length measuring device be used in a room where the change in atmospheric pressure is extremely small.

  For example, Patent Literature 1 and Patent Literature 2 disclose devices for reducing changes in atmospheric pressure in a room. In Patent Document 1, as shown in FIG. 1, an external air fan 3 on the supply side and an exhaust fan 14 on the exhaust side are controlled by inverter units 20 and 21, respectively. A technique for suppressing fluctuations in atmospheric pressure is disclosed.

Further, in Patent Document 2, as shown in FIG. 1, an air supply amount adjuster 12 and an exhaust amount adjuster 16 are appropriately controlled by a control box 17 to respectively supply an air supply fan 11 and an exhaust air. A technique is disclosed in which the amount of air blown by the fan 15 can be adjusted and the atmospheric pressure in the room 10 can be finely adjusted.
JP-A-1-277149 JP 2001-304039 A

  By the way, it is possible to control the indoor pressure using the techniques disclosed in Patent Document 1 and Patent Document 2, but when the differential pressure between the outside air pressure and the target set atmospheric pressure is small. The output of the air pressure pressurizing device and the exhaust pressure reducing device provided in the chamber is reduced. Since the air blowing capacity of these devices in the low output region is unstable, the atmospheric pressure control in the room becomes unstable.

  Therefore, an object of the present invention is to provide a control device for an absolute pressure control chamber that can accurately adjust the indoor atmospheric pressure to a target set atmospheric pressure.

In order to solve the above-mentioned problems, the invention of claim 1 is provided with an air supply passage provided with a blowing means and an exhaust passage provided with an exhaust means, and an absolute length meter for disposing an optical length measuring device therein. In the pressure control chamber, the minimum output value is set to the output values of the air blowing means and the exhaust means, and when the target set atmospheric pressure in the absolute pressure control chamber is higher than the external air pressure, the output value of the exhaust means is When the output value of the blowing means is set so as not to fall below the minimum output value, and the target set atmospheric pressure in the absolute pressure control chamber is lower than the outside air pressure, the output value of the blowing means is the minimum output The output value of the exhaust means is set so as not to fall below the value, and the atmospheric pressure in the absolute pressure control chamber is brought close to the target set atmospheric pressure or the target set atmospheric pressure is maintained .
An air flow meter may be provided in each of the air supply passage and the exhaust passage. The air pressure in the absolute pressure control chamber may be controlled based on the air amount actually measured by each air flow meter.

According to a second aspect of the present invention, in the air pressure control device according to the first aspect of the present invention, the air blowing means includes a motor damper and a blower, and the minimum output value is a lower limit value of the opening degree of the motor damper and / or the The minimum output value of the blower was used.

According to a third aspect of the present invention, in the atmospheric pressure control apparatus according to the first or second aspect, the exhaust means includes a motor damper and a blower, and the minimum output value is a lower limit value of the opening degree of the motor damper and / or Or it was set as the minimum output value of the said air blower.

According to a fourth aspect of the present invention, in the atmospheric pressure control device according to any one of the first to third aspects, if the output values of the blower means and the exhaust means are equal to or greater than the minimum output value, 5% of the total volume of the absolute pressure control chamber. The air amount corresponding to% to 20% was changed in 1 hour.

According to a fifth aspect of the present invention, in the atmospheric pressure control device according to any one of the first to fourth aspects, the absolute pressure control chamber is constituted by a panel.

  When the invention of claim 1 is carried out, the minimum output value is set to the output values of the blowing means provided in the air supply passage and the exhaust means provided in the exhaust passage, and the output values of the blowing means and the exhaust means are less than the minimum output values. Therefore, the atmospheric pressure in the absolute pressure control chamber can be satisfactorily adjusted to the target set atmospheric pressure.

In the second and third aspects of the present invention, the blower means and the exhaust means have a motor damper and a blower, and the minimum output value is set as a lower limit value of the opening degree of the motor damper and / or a minimum output value of the blower. Therefore, similarly to the first aspect of the invention, the atmospheric pressure in the absolute pressure control chamber can be well adjusted to the target set atmospheric pressure.

In the invention of claim 4, when the output values of the blower means and the exhaust means are equal to or higher than the minimum output value, the air amount corresponding to 5% to 20% of the total volume of the absolute pressure control chamber is switched in one hour. Therefore, it is possible to adjust the target set pressure while ventilating the absolute pressure control chamber well.

In the invention of claim 5 , since the absolute pressure control chamber is constituted by a panel, in addition to the effects of the inventions of claims 1 to 4, there are less space restrictions for using the optical length measuring device. Furthermore, a processing machine such as an existing optical length measuring device can be easily accommodated in an absolute pressure control chamber constituted by a panel. If the floor is flat, the absolute pressure control chamber can be formed simply by surrounding the side and ceiling with panels.

  FIG. 1 is a system schematic diagram of an atmospheric pressure control apparatus 1 that implements the present invention for controlling the atmospheric pressure in an absolute pressure control chamber 2. As shown in FIG. 1, the atmospheric pressure control device 1 includes a pressurizing device 3 (air blowing means) that supplies air to the absolute pressure control chamber 2 via an air supply passage 41 and an absolute pressure control chamber 2 via an exhaust passage 42. The pressure reducing device 4 (exhaust means) for discharging the air inside, and the pressure device 3 and the control device 5 for controlling the pressure reducing device 4 are configured.

  The control device 5 includes a CPU 14 and a memory 15. The CPU 14 performs various calculations described later, and the memory 15 stores various values described later. The control device 5 controls the pressurization device 3 and the decompression device 4 so that the atmospheric pressure in the absolute pressure control chamber 2 becomes a predetermined value (target set atmospheric pressure).

  As shown in FIG. 1, the pressurizing device 3 includes an inverter 6, a pressurizing device 7, and a motor damper 8. The inverter 6 receives a command signal from the control device 5 via the signal line 21 and adjusts the output of the pressurizing device 7 via the signal line 22. As the pressurizing device 7, a blower fan, an air compressor, or the like can be employed.

  The motor damper 8 receives a command signal from the control device 5 via the signal line 23, adjusts the opening degree (flow passage cross-sectional area) of the air supply passage 41, and the amount of air per unit time passing through the air supply passage 41. It has a function as a control valve that adjusts. Therefore, the amount of air (ventilation amount) supplied to the absolute pressure control chamber 2 can be arbitrarily set by setting the output (blowing force) of the pressurizing device 7 and setting the opening of the motor damper 8. ing.

  As shown in FIG. 1, a ventilation flow meter 9 may be provided in the air supply passage 41. The ventilation flow meter 9 detects the amount of air (ventilation amount) supplied into the absolute pressure control chamber 2 via the air supply passage 41. That is, the ventilation flow meter 9 functions as an output value detection unit that detects the output of the pressurizing device 3 (the pressurizing device 7 and the motor damper 8). The output value of the pressure device 3 is determined by a combination of the blowing force of the pressure device 7 and the opening degree of the motor damper 8. The ventilation flow meter 9 transmits the detected air amount information to the control device 5 via the signal line 24. The control device 5 refers to the air amount information and controls the pressurizing device 3 so that the atmospheric pressure in the absolute pressure control chamber 2 becomes the target set atmospheric pressure.

  The configuration on the supply side (FIG. 1) for supplying air into the absolute pressure control chamber 2 has been described above, but the configuration on the exhaust side (FIG. 1) for discharging air in the absolute pressure control chamber 2 will be described below. Will be described.

  As shown in FIG. 1, the decompression device 4 includes an inverter 10, a decompression device 11, and a motor damper 12. The inverter 10 receives a command signal from the control device 5 via the signal line 25 and adjusts the output of the decompression device 11 via the signal line 26. As the decompression device 11, a blower fan, a vacuum pump, or the like can be employed. The output value of the decompression device 4 is determined by the combination of the blowing force of the decompression device 11 and the opening degree of the motor damper 12.

  The motor damper 12 receives a command signal from the control device 5 via the signal line 27, adjusts the opening degree (flow passage cross-sectional area) of the exhaust passage 42, and adjusts the amount of air per unit time passing through the exhaust passage 42. It has a function. Therefore, the amount of air discharged from the absolute pressure control chamber 2 (ventilation amount) can be arbitrarily set by setting the output of the decompression device 11 and setting the flow path cross-sectional area of the motor damper 12.

  As shown in FIG. 1, a ventilation flow meter 13 may be provided in the exhaust passage 42. The ventilation flow meter 13 detects the amount of air (ventilation amount) discharged from the absolute pressure control chamber 2 through the exhaust passage 42. That is, the ventilation flow meter 13 functions as an output value detection unit that detects the output of the decompression device 4 (the decompression device 11 and the motor damper 12). The output value of the decompression device 4 is determined by the combination of the blowing force of the decompression device 11 and the opening degree of the motor damper 12. The ventilation flow meter 13 transmits the detected air amount information to the control device 5 via the signal line 28. The control device 5 refers to the air amount information and controls the decompression device 4 so that the atmospheric pressure in the absolute pressure control chamber 2 becomes the target set atmospheric pressure.

  As shown in FIG. 1, a pressure detector 16 is installed in the absolute pressure control chamber 2. The pressure detector 16 detects the atmospheric pressure in the absolute pressure control chamber 2 and transmits the detected value to the control device 5 via the signal line 31. In addition, a pressure detector 17 that detects the external atmospheric pressure is installed outside the absolute pressure control chamber 2. The pressure detector 17 detects the external atmospheric pressure and transmits the detected value to the control device 5 via the signal line 32.

  At the time of pressurization (when the atmospheric pressure in the absolute pressure control chamber 2 is set higher than the external atmospheric pressure), the air pressure is supplied from the air supply passage 41 after the atmospheric pressure in the absolute pressure control chamber 2 becomes the target set atmospheric pressure. The amount of air to be discharged (ventilation amount) is equal to the sum of the amount of air discharged from the exhaust passage 42 and the amount of air leaking from the absolute pressure control chamber 2 (leakage air 18 in FIG. 2).

  Further, at the time of decompression (when the atmospheric pressure in the absolute pressure control chamber 2 is set lower than the external atmospheric pressure), from the supply passage 41 after the atmospheric pressure in the absolute pressure control chamber 2 becomes the target set atmospheric pressure. The sum of the amount of air supplied and the amount of air that enters the absolute pressure control chamber 2 through any gap (intrusion air 19 in FIG. 3) is the amount of air discharged from the exhaust passage 42 (ventilation amount). equal.

  In the control device 5, the amount of air supplied to the absolute pressure control chamber 2 is equal to the amount of air discharged from the absolute pressure control chamber 2 in a state where the atmospheric pressure in the absolute pressure control chamber 2 is set to the target set atmospheric pressure. Thus, the pressurizing device 3 and the decompressing device 4 are controlled. Thereby, it can avoid that the output value of the pressurization apparatus 3 and the decompression device 4 is less than the minimum output value, keeping the atmospheric | air pressure in the absolute pressure control chamber 2 constant (target setting atmospheric | air pressure).

  At the time of pressurization, the control device 5 calculates an appropriate opening degree of the motor damper 8 and an output value of the inverter 6 from the deviation between the target set atmospheric pressure and the atmospheric pressure actually measured by the pressure detector 16, and outputs it to the motor damper 8 and the inverter 6. Send a signal. Inverter 6 adjusts the output of pressurizing device 7 in accordance with the output signal received from control device 5. The pressurizing device 7 whose output is adjusted in this way is configured to bring the atmospheric pressure in the absolute pressure control chamber 2 close to the target set atmospheric pressure or to maintain the target set atmospheric pressure via the air supply passage 41. Air is supplied to the absolute pressure control chamber 2.

  Further, the control device 5 allows the air amount corresponding to, for example, 5% to 20% of the total volume of the absolute pressure control chamber 2 to be switched in one hour (that is, the outputs of the pressurizing device 3 and the decompressing device 4 are the minimum output values). The air supply amount by the pressurization device 3 and the air discharge amount by the decompression device 4 are controlled simultaneously. Thereby, it can avoid that the atmospheric | air pressure in the absolute pressure control chamber 2 is set to the target setting atmospheric | air pressure, and the output value of the pressurization apparatus 3 and the pressure reduction apparatus 4 is less than the minimum output value.

  FIG. 2 is a system diagram showing a signal flow of the atmospheric pressure control device 1 during pressurization. In FIG. 2, the control device 5 sets the target in the absolute pressure control chamber 2 based on the deviation between the atmospheric pressure in the absolute pressure control chamber 2 detected by the pressure detector 16 and the external atmospheric pressure detected by the pressure detector 17. The amount of supply air for making the air pressure is calculated, the amount of supply air for preventing the output value of the decompression device 4 from reaching the minimum output value is calculated, and an output signal is transmitted to the inverter 6. Thereby, the air amount corresponding to the sum of the air amount for setting the inside of the absolute pressure control chamber 2 to the target set atmospheric pressure and the air amount for preventing the output value of the decompression device 4 from reaching the minimum output value is obtained. The absolute pressure control chamber 2 is supplied.

  As shown in FIG. 2, at the time of pressurization, part of the air in the absolute pressure control chamber 2 flows out from the absolute pressure control chamber 2 as the leaked air 18 without passing through the exhaust passage 42. Therefore, at the time of pressurization, in order to keep the atmospheric pressure in the absolute pressure control chamber 2 constant (target set atmospheric pressure), the amount of air discharged by the decompression device 4 is supplied by the pressurization device 3 by the amount of the leaked air 18. The control device 5 controls the pressure reducing device 11 and the control valve 12 (motor damper 12) so as to be smaller than the amount of air.

  At the time of pressurization, when the opening degree of the motor damper 12 on the exhaust passage 42 becomes smaller than a lower limit value (for example, 30% opening degree) or the output of the decompression device 11 reaches the minimum output value, Since the operation becomes unstable, precise atmospheric pressure control cannot be performed, and sufficient ventilation cannot be ensured (that is, the output of the decompression device 4 is less than the minimum output value). In order to prevent the opening degree of the motor damper 12 from reaching the lower limit value, or to increase the amount of air supplied by the pressurization device 3 so that the output of the decompression device 11 does not reach the minimum output value, or the pressurization device Each device is controlled so as not to further reduce the amount of air supplied by 3.

  At the time of pressure reduction, the control device 5 calculates an appropriate opening degree of the motor damper 12 and an output value of the inverter 10 from the deviation between the target set atmospheric pressure and the atmospheric pressure actually measured by the pressure detector 16, and outputs an output signal to the motor damper 12 and the inverter 10. To emit. Inverter 10 adjusts the output of decompression device 11 in accordance with the output signal received from control device 5. The decompression device 11 whose output has been adjusted in this way allows the air pressure in the absolute pressure control chamber 2 to be brought close to the target set atmospheric pressure, or the air is passed through the exhaust passage 42 so that the target set atmospheric pressure can be maintained. Discharge from the absolute pressure control chamber 2.

  Further, the control device 5 allows the air volume corresponding to, for example, 5% to 20% of the total volume of the absolute pressure control chamber 2 to be switched in one hour (that is, the outputs of the pressurizing device 3 and the decompressing device 4 are the minimum output). The air discharge amount by the decompression device 4 and the air supply amount by the pressurization device 3 are controlled simultaneously (so as not to fall below the value). Thereby, it can avoid that the atmospheric | air pressure in the absolute pressure control chamber 2 is set to the target setting atmospheric | air pressure, and the output value of the pressurization apparatus 3 and the pressure reduction apparatus 4 is less than the minimum output value.

  FIG. 3 is a system diagram showing a signal flow of the atmospheric pressure control device 1 during decompression. In FIG. 3, the control device 5 sets the target in the absolute pressure control chamber 2 from the deviation between the atmospheric pressure in the absolute pressure control chamber 2 detected by the pressure detector 16 and the external atmospheric pressure detected by the pressure detector 17. An exhaust air amount for calculating the atmospheric pressure is calculated, an exhaust air amount for preventing the output value of the pressurizing device 3 from reaching the minimum output value is calculated, and an output signal is transmitted to the inverter 10. This corresponds to the sum of the amount of exhaust air for setting the inside of the absolute pressure control chamber 2 to the target set atmospheric pressure and the amount of exhaust air for preventing the output value of the pressurizing device 3 from reaching the minimum output value. The amount of air to be discharged is discharged from the absolute pressure control chamber 2.

  As shown in FIG. 3, outside air flows into the absolute pressure control chamber 2 as the intruding air 19 without passing through the air supply passage 41 during decompression. Therefore, at the time of decompression, in order to keep the atmospheric pressure in the absolute pressure control chamber 2 constant (target set atmospheric pressure), the amount of air supplied by the pressurizer 3 is exhausted by the decompressor 4 by the amount of the intruding air 19. The control device 5 controls the pressurizing device 7 and the control valve 8 (motor damper 8) so as to be smaller than the amount of air to be performed.

  During decompression, when the opening degree of the motor damper 8 on the air supply passage 41 becomes smaller than a lower limit value (for example, opening degree 30%) or when the output of the pressurizing device 7 reaches the minimum output value, The operation of the pressure device 7 becomes unstable, it becomes impossible to perform precise atmospheric pressure control, and sufficient ventilation cannot be secured (that is, the output of the pressurizing device 3 (FIG. 1) is less than the minimum output value). Therefore, the control device 5 uses the air from the decompression device 4 (FIG. 1) so that the opening degree of the motor damper 8 does not reach the lower limit value or the output of the pressurizing device 7 does not reach the lowest output value. Each device is controlled so as to increase the amount of air discharged or to prevent further reduction of the amount of air discharged by the decompression device 4.

  FIG. 4 is a schematic plan view of the absolute pressure control chamber 2 surrounded by a heat insulating panel 45. As shown in FIG. 4, the absolute pressure control chamber 2 includes an entrance 46. The doorway 46 has a structure in which an outer door 35 and an inner door 36 are provided at both ends of a passage surrounded by the heat insulating panel 44. The heat insulation panels 45 and 44 are connected in an airtight manner. The heat insulation panels 44 and 45 have, for example, a structure in which a foam material is sandwiched between thin steel plates. If it is not necessary to control the temperature in the absolute pressure control chamber 2, the absolute pressure control chamber 2 may be constituted by a panel having no heat insulation function.

  FIG. 5A is a perspective view of the absolute pressure control chamber 2 constituted by the panel 45. FIG. 5B is a perspective view of the panel 45. As shown in FIG. 5B, protrusions 47, 47a, depressions 48, 48a, 48b, and the like are appropriately provided on the edge of the panel 45. As shown in FIG. 5A, adjacent panels 45 are assembled by fitting these protrusions and recesses to form the absolute pressure control chamber 2.

  As shown in FIG. 4, a pressure adjusting chamber 2 a is formed in the entrance 46. As shown in FIG. 4, the absolute pressure control chamber 2 is provided with a differential pressure gauge 50 that can measure the differential pressure between the atmospheric pressure in the pressure adjustment chamber 2 a and the atmospheric pressure in the absolute pressure control chamber 2. The CPU 51 adjusts the air pressure in the pressure adjustment chamber 2 a by controlling the pressure-side blower 52 and the motor valve 54 or the pressure-reduction side blower 53 and the motor valve 55 from the differential pressure information detected by the differential pressure gauge 50. To do. At normal times (when there is no person going in and out), the pressure in the pressure adjustment chamber 2a when the inside of the absolute pressure control chamber 2 is pressurized is matched with the atmospheric pressure. It is preferable that the atmospheric pressure in the pressure adjusting chamber 2a when the pressure is reduced is made to coincide with the set atmospheric pressure in the absolute pressure control chamber 2. When the outer door 35 is a hinge-type outer opening and the inner door 36 is a hinge-type inner opening, when the inside of the absolute pressure control chamber 2 is pressurized, the sealing performance of the inner door 36 is improved, and conversely When the absolute pressure control chamber 2 is depressurized, the sealing performance of the outer door 35 is improved.

  When a person tries to enter the absolute pressure control chamber 2 from the outside, first, only the outer door 35 is opened, and after the person enters the pressure adjusting chamber 2a, the outer door 35 is closed. At this time, the pressure in the pressure adjusting chamber 2a is equal to the atmospheric pressure. After adjusting the atmospheric pressure in the pressure adjustment chamber 2a so that the atmospheric pressure in the pressure adjustment chamber 2a becomes equal to the atmospheric pressure in the absolute pressure control chamber 2, the inner door 36 is opened, and the person in the pressure adjustment chamber 2a is absolutely Enters the pressure control chamber 2 and closes the inner door 36.

  On the contrary, when a person in the absolute pressure control chamber 2 exits, first, it is checked whether or not the atmospheric pressure in the pressure adjustment chamber 2a is equal to the atmospheric pressure in the absolute pressure control chamber 2. The atmospheric pressure in the pressure adjustment chamber 2a is adjusted. If the atmospheric pressure in the pressure adjustment chamber 2a is equal to the atmospheric pressure in the absolute pressure control chamber 2, the inner door 36 is opened and a person in the absolute pressure control chamber 2 enters the pressure adjustment chamber 2a. And after closing the inner door 36, the person in the pressure regulation chamber 2a opens the outer door 35, and leaves. Here, it is preferable that the person inside the pressure adjusting chamber 2a gradually exits the pressure adjusting chamber 2a by opening the outer door 35 after gradually increasing the pressure inside the pressure adjusting chamber 2a.

  Further, instead of using the blower 52 for forcibly supplying air to the pressure adjustment chamber 2a and the blower 53 for forcibly discharging air from the pressure adjustment chamber 2a, the inside of the pressure adjustment chamber 2a and the absolute pressure control chamber 2 are used. An air passage communicating with the inside is formed, and an electromagnetic valve is provided on the air passage. By opening the electromagnetic valve, the atmospheric pressure (atmospheric pressure) in the pressure adjusting chamber 2a is gradually reduced in the absolute pressure control chamber 2. It may be made to coincide with the atmospheric pressure. Furthermore, an air passage is provided to communicate the pressure adjustment chamber 2a with the outside (atmosphere), and an electromagnetic valve is provided on the air passage. By opening the electromagnetic valve, the pressure in the pressure adjustment chamber 2a matches the atmospheric pressure. You may make it make it.

  In the absolute pressure control chamber 2 constituted by such a heat insulating panel 45, it is difficult to keep completely airtight even if the pressure adjusting chamber 2a is provided. However, by implementing the atmospheric pressure control device 1 of the present invention, the atmospheric pressure in the absolute pressure control chamber 2 can be kept at the target set atmospheric pressure in consideration of air leakage.

  When the measured value of the atmospheric pressure in the absolute pressure control chamber 2 approaches the target set pressure, or when the difference between the target set pressure and the external pressure is small, or the target set pressure is higher than the atmospheric pressure, When the pressure applied by the pressure device 3 becomes considerably high, or when the target set atmospheric pressure is lower than the atmospheric pressure and the pressure reduction force by the pressure reduction device 4 becomes considerably high, the pressure device 3 or the pressure reduction device 4 is apt to be set to a low output value. However, when the invention of claim 1 or 2 is implemented, the minimum output value is provided for the output values of the pressurization device 3 and the decompression device 4. Further, it is possible to avoid the outputs of the pressurization device 3 and the decompression device 4 from being low, and the atmospheric pressure in the absolute pressure control chamber 2 can be accurately adjusted to the target set atmospheric pressure.

1 is a system schematic diagram of a barometric pressure control device of the present invention for ventilating an absolute pressure control chamber. It is the system | schematic diagram of the atmospheric | air pressure control apparatus at the time of pressurizing an absolute pressure control chamber. It is the system | schematic diagram of the atmospheric | air pressure control apparatus at the time of decompressing an absolute pressure control chamber. 1 is a schematic plan view of an absolute pressure control chamber in which an atmospheric pressure control device of the present invention is implemented. (A) is a perspective view of the absolute pressure control chamber comprised with the panel. (B) is a perspective view of a panel.

DESCRIPTION OF SYMBOLS 1 Atmospheric pressure control apparatus 2 Absolute pressure control room 3 Pressurization apparatus (blower means)
4 Pressure reducing device (exhaust means)
DESCRIPTION OF SYMBOLS 5 Control apparatus 6 Inverter 7 Pressurization apparatus 8 Motor damper 9 Ventilation flow meter 10 Inverter 11 Depressurization apparatus 12 Motor damper 13 Ventilation flow meter 18 Leakage air 19 Intrusion air 21-28, 31, 32 Signal wire 35 Outer door 36 Inner door 41 Supply air Passage 42 Exhaust passage 44, 45 Heat insulation panel 46 Entrance / exit

Claims (5)

In an absolute pressure control chamber for providing an air supply passage provided with a blowing means and an exhaust passage provided with an exhaust means, and for disposing an apparatus that is susceptible to atmospheric pressure fluctuations such as an optical length measuring instrument inside. ,
Set the minimum output value to the output value of the blower means and the exhaust means,
In the case where the target set atmospheric pressure in the absolute pressure control chamber is higher than the external atmospheric pressure, the output value of the blower means is set so that the output value of the exhaust means does not fall below the minimum output value,
When the target set atmospheric pressure in the absolute pressure control chamber is lower than the external atmospheric pressure, the output value of the exhaust means is set so that the output value of the air blowing means does not fall below the minimum output value, and the absolute pressure An air pressure control device for an absolute pressure control chamber, characterized in that the air pressure in the control chamber is brought close to the target set air pressure or the target set air pressure is maintained . The said blower means has a motor damper and a blower, and the said minimum output value is the minimum value of the opening degree of the said motor damper, and / or the minimum output value of the said fan. Barometric pressure control device for absolute pressure control room. The exhaust means includes a motor damper and a blower, and the minimum output value is a lower limit value of an opening degree of the motor damper and / or a minimum output value of the blower. The absolute pressure control chamber of the described absolute pressure control chamber. The air amount corresponding to 5% to 20% of the total volume of the absolute pressure control chamber is switched in one hour when the output values of the blower means and the exhaust means are equal to or higher than the minimum output value. 4. The atmospheric pressure control device for an absolute pressure control chamber according to any one of 3 above. The absolute pressure control chamber, pressure control device for absolute pressure control chamber according to any one of claims 1 to 4, characterized in that configured in the panel.

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