JP5007877B2 - Gas circulation purification equipment - Google Patents

Description

  The present invention is a case storage type blower characterized in that the electric blower is housed in a case with good airtightness, and particularly in a gas circulation purification device for removing oxygen and moisture in an inert gas such as nitrogen gas or argon gas. It is related with the ventilation mechanism used suitably.

  There is a desire to handle an active metal that reacts violently with oxygen or moisture in an inert gas and a desire to assemble an organic EL (organic light emitting diode) display panel that deteriorates with time due to moisture in an atmosphere without moisture. For this purpose, a gas circulation purification apparatus is connected to a closed box which is a work place where a tight seal is ensured, such as a glove box. The gas circulation purification apparatus is an apparatus having a function of removing impure components in the inert gas fed from the sealed box and returning the purified inert gas to the sealed box. “Gas circulation” is a name given by circulating an inert gas between the closed box and the gas circulation purification apparatus. The inert gas mentioned here refers to a gas that does not contain a gas that should not be present in the sealed box, but usually argon, nitrogen, or helium is used. The impure component in the inert gas refers to a gas that hinders the work in the sealed box or a gas that deteriorates the properties of the product produced by the work, but usually includes oxygen and moisture. In some cases, vapors of organic substances may be impure components.

  FIG. 3 shows the main components of the gas circulation purification apparatus. Reference numeral 19 in FIG. 3 denotes a gas circulation purification apparatus, which has a gas inlet 20 and a gas outlet 21, both of which are connected to the above-mentioned sealed box by piping. The inert gas entering from the gas inlet 20 enters the purification tower 13, moisture is removed by the moisture adsorbent 14 accommodated in the purification tower, and oxygen is removed by the oxygen adsorbent 15. A typical example of the moisture adsorbent is molecular sieve, and a typical example of the oxygen adsorbent is reduced copper. In the figure, 4 is an electric motor (motor), 5 is a blower mechanism, 6 is a rotating shaft, and 12 is a fan for cooling the motor. The blower mechanism 5 is driven by the motor to blow the inert gas. Since the gas is repeatedly pressurized and stirred by the blowing mechanism, the gas temperature rises due to the thermodynamic principle. In particular, when the discharge pressure is high, the temperature rises greatly and sometimes exceeds 50 ° C. Therefore, a cooling tower 16 having a function of cooling the inert gas is installed. 17 and 18 in the figure are cooling water entrances and exits. As an example of the cooling mechanism, a shell and tube structure known as a heat exchanger having a structure that is cooled when a gas passes through a plurality of tubes disposed in flowing cooling water can be given. With the above configuration, the inert gas that has entered the gas circulation purification device 19 from the inlet 20 is delivered from the outlet 21 and returned to the sealed box after impurities are removed.

  In the example of FIG. 3, the inert gas enters the electric blower after passing through the purification tower 13. In this configuration, the molecular sieve is not heated by the gas whose temperature has been raised by the electric blower. Therefore, there is an advantage that the cooling tower can be omitted if there is no problem even if the temperature of the gas exiting the gas circulation purification apparatus is slightly higher than room temperature. On the contrary, it can also be set as the structure which enters a refinement tower after passing an electric blower. In this configuration, minute oils mixed with the electric blower can be adsorbed and removed with a molecular sieve, and even if minute air is mixed in the electric blower, oxygen and moisture can be removed with a purification tower placed after that. There is. However, in this configuration, an increase in the gas temperature causes an increase in the molecular sieve temperature, leading to a deterioration in moisture adsorption performance, so that the inert gas is cooled more strictly, so that the cooled inert gas enters the purification tower. There is a need to.

  As the electric blower used, any type of electric blower in which the blower mechanism is rotationally driven by a motor can be used. These electric blowers are often called blowers, fans, dry pumps and the like. A Roots blower in which a pair of three-leaf rotors rotate while maintaining a minute gap is an electric blower that has a small dependency on the air volume of the discharge pressure and is effective in securing a stable gas circulation air volume in a circulating gas system with a large pressure loss. A ring blower and a side channel blower are relatively small and have a high discharge pressure and a large air volume. In addition, a turbo fan or a sirocco fan may be used.

  The required level of oxygen concentration and moisture concentration in the circulated inert gas is often 1 ppm or less, and in some cases, there is a requirement of ppb (parts per billion) level. Requires a completely sealed structure free from atmospheric contamination. However, none of the conventional inexpensive electric blowers that are mass-produced satisfy the required specifications. The airtightness of the blower mechanism (5 in FIG. 3) is poor. The part where the rotating shaft (6 in FIG. 3) connecting the motor (4 in FIG. 3) and the blower mechanism (5 in FIG. 3) enters the blower mechanism is a bearing. There is a drawback that only the sealing member for preventing the dust from adhering to the bearing is used and the sealing performance is not good. Therefore, the blower mechanism is manufactured by special design and production without using low-priced mass-produced products, or the oil in the shaft seal part in the blower having an expensive but good airtightness such as the Roots blower. In order to withstand both the positive pressure and the reduced pressure, the seal is doubled or modified so that it is put into practical use. Although it was possible to improve the sealing and sealing properties by such means, it is necessary to disassemble and inspect every 1 to several years so that oil seals etc. are gradually worn out. However, the drawbacks of being prone to failure or high maintenance costs have not been solved. In addition, the motor of the electric blower needs to be cooled, usually with a small blower (fan, 12 in FIG. 3), but this fan soars dust or disturbs the air flow to install in a clean room There are many cases where this is not possible.

  In view of this situation, the present inventors have disclosed a case storage type blower suitable for a gas circulation purification device in Japanese Patent Application No. 2006-039933, which is a compact and highly reliable electric blower using mass-produced inexpensive products. Proposed. This case storage type blower was a significant advance compared to the conventional case, but the motor is overheated when it is desired to make the circulating gas air volume variable for the purpose of high functionality, especially when it is desired to increase the circulating gas air volume. Problem has occurred. In addition, in the proposed case storage type blower, there are restrictions on the arrangement of the gas inlet / outlet of the case and the electric blower, so it is not possible to freely select an electric blower with good cost performance, and the case design is less flexible and as a result, compactness is sacrificed. The problem of becoming.

  The present invention proposes an improved case-housing fan. The present invention has been made for the purpose of increasing the degree of freedom in designing a case, which can be suitably used when a motor generates heat as compared with a conventional product, and the selection range of a commercially available electric blower is widened.

  That is, according to the present invention, the electric blower is housed in a case with good airtightness, the case is provided with a gas inlet and outlet, and after the gas that has entered from the inlet spreads in the case, the electric blower is placed in the blower mechanism portion of the electric blower. The case where the gas blown by the blower mechanism and sent out from the blower mechanism portion is not discharged into the case by connecting the gas outlet of the blower mechanism and the gas outlet of the case. And a fan that cools the motor of the electric blower is provided in the case, and is a case storage type blower used in a system that dislikes mixing of air. Or, the configuration in which the gas inlet / outlet is reversed, that is, the electric blower is housed in a case with good airtightness, the case is provided with a gas inlet and outlet, and the gas entering from the inlet is connected to the case inlet and the electric motor When the inlet of the blower mechanism portion of the blower is connected, the gas that enters the blower mechanism portion without being discharged into the case, is blown by the blower mechanism, and is sent from the blower mechanism portion in the case. A case storage type used in a system that dislikes air mixing, characterized in that it is sent out from the outlet of the case after spreading to the case, and further a fan for cooling the electric fan of the electric blower is provided in the case It is a blower. In the former configuration, that is, when the gas entering from the inlet flows so as to cool the motor of the electric blower, the temperature of the gas striking the motor is almost normal temperature, which is convenient for cooling the motor. In the case of the latter structure, that is, a structure in which the gas sent out from the air blowing mechanism flows to cool the motor and then sent out from the outlet of the case, the motor is cooled with the gas warmed by the air blowing mechanism. Although it is a demerit from the viewpoint of motor cooling, a small amount of oil generated in the rotating part of the blower mechanism is not sent directly from the gas outlet, but is discharged into the case once and then into the case wall. It has a secondary effect of being removed. Further, this latter configuration is convenient when a cooling mechanism described later is provided inside the case. The choice between the former and the latter is determined by the requirements of the work in a closed box such as a glove box used.

  Although the case storage type blower of the present invention can be used for all air blowing systems that do not allow air to be mixed, it is particularly useful in a sealed box such as a glove box that requires a very low moisture content and / or a low oxygen content. It is preferably used in a gas circulation purification apparatus that circulates and supplies gas to the gas and performs gas purification in the middle of the gas. In addition, the above-mentioned objection to air mixing means to dislike mixing one or more components in the air, and usually means to dissociate one or more of oxygen, nitrogen and moisture. . Therefore, the gas blown by the case storage type blower of the present invention may be any gas or mixed gas as long as it is a gas that dislikes one or more components in the atmosphere, but in particular, an inert gas is used. As the inert gas, nitrogen and argon are preferably used from the viewpoints of price and availability.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Reference numeral 1 in FIG. 1 denotes a case of the case storage type blower of the present invention. The case 1 needs to be manufactured with good airtightness. Usually, the case 1 is made of stainless steel, and the manufactured case is used as a product after being inspected for leaks by a helium leak detector and confirmed that there is no leakage. Although not shown, an electric cable for driving the motor 4 is introduced into the case through a current introduction mechanism (hermetic seal or the like) having a good sealing property through the case wall and connected to the motor. The air volume can be made variable by changing the rotation speed of the motor with an inverter. There are many requests to change the wind speed depending on the size of the glove box and the work contents. 1 is a gas inlet, and 3 in FIG. 1 is a gas outlet. A part of the gas entering from the inlet cools the motor 4 of the electric blower while spreading in the case, enters the inlet 7 of the blower mechanism 5, is pressurized and blown out from the outlet 8 of the blower mechanism. The gas delivered from the outlet 8 of the blower mechanism goes out from the outlet 3 of the case without leaking into the case. Reference numeral 22 in FIG. 1 denotes a fan for cooling the electric motor (motor). Reference numeral 23 denotes a motor for driving the cooling fan, and reference numeral 24 denotes a rotary seal mechanism. In addition, the broken line arrow of this figure shows the gas flow typically.

  In this configuration, all the above-mentioned conventional problems can be solved at once. First, in the present invention, the airtightness of the electric blower itself is not a problem. By manufacturing the case (1 in FIG. 1) with good airtightness, air does not enter the blown gas. Next, in the present invention, a fan 22 for cooling the motor 4 is provided. The gas whose flow rate is increased by the fan 22 cools the motor 4 efficiently. In FIG. 1, the fan 22 is rotationally driven by a motor 23 installed outside the case. The rotary shaft is sealed by the rotary seal mechanism 24 so that the atmosphere does not enter the case 1. A combination of a bearing and an oil seal can be used as the rotary seal mechanism. More preferably, a magnetic fluid seal or a magnetic coupling can be used. With this configuration, a stable cooling effect can be obtained regardless of the rotational speed of the motor 4 of the electric blower. It is also possible to attach a fan 22 for cooling the motor to the rotating shaft of the motor 4 as indicated by 12 in FIG. In this case, the configuration is simplified and the merit of reducing the number of parts is great. However, since it is linked to the rotational speed of the motor 4, there is a demerit that the motor is not sufficiently cooled at a slow rotational speed. Next, the gas flow will be described. The gas that has entered the case from the case inlet 2 spreads into the case and is sucked into the inlet 7 of the blower mechanism 5. During this time, the gas cools the motor 4 by the natural flow of gas and the forced flow by the fan 22. The gas pressurized and blown by the blower mechanism passes through the connecting pipe from the gas outlet 8 of the blower mechanism and is sent out from the case outlet 3. Since the gas temperature at the case outlet is usually higher than the gas temperature at the case inlet, some kind of gas cooling mechanism (not shown) is required. As is clear from the above configuration, the case-accommodating blower of the present invention only includes the small motor 23 and obstructs the flow of clean air in the clean room even if it is installed in a clean room without blowing air out of the case. There is no.

  FIG. 2 illustrates a further development of the present invention. 1 to 7 and 22, 23, 24 in this figure are the same as those in FIG. Reference numerals 9, 10, and 11 denote gas cooling mechanisms. In this example, the cooling plate 9 is schematically shown in which cooling water is connected to a water cooling pipe in which cooling water flows from the inlet 10 to the outlet 11 with good heat conduction. The gas temperature decreases as the gas flows while hitting the plurality of cooling plates 9. Such a structure is known as an erotic fin tube heat exchanger or a plate fin tube heat exchanger, and other known gas cooling mechanisms can be used. Compared with the conventional system in which cooling towers are individually installed as shown in FIG. 3, the present invention makes it possible to manufacture the gas circulation purification apparatus main body in a compact and inexpensive manner.

  In FIG. 2, the gas that has entered from the case inlet 2 is pressurized and blown by the blower mechanism 5, exits from the blower mechanism outlet 8, cools by the cooling mechanism 9 after cooling the motor 4, and exits from the case outlet 3. The configuration is shown. This configuration is advantageous because a sufficiently cooled gas can be delivered from the outlet 3. Conversely, the gas flow can be in the same direction as in FIG. That is, the configuration is such that the gas entered from the case inlet passes through the cooling mechanism and then cools the motor before entering the blower mechanism, or the gas entered from the case inlet cools the motor and then passes through the cooling mechanism, and finally blows. It can also be set as the structure which enters into a mechanism. The configuration in which these gas flows are in the same direction as in FIG. 1 is advantageous from the viewpoint of motor cooling because the motor is cooled before the gas is heated by the blower mechanism. As described above, the arrangement of these component parts may not be exact, but the fan 22 needs to be arranged so as to cool the motor 4.

  In general, the circulation gas flow rate of a commercially available gas circulation purification apparatus is about 10 cubic meters / hour to about 120 cubic meters / hour. In the case storage type blower, if the gas inlet 2, the gas outlet 3, the motor 4, and the blower mechanism 5 are effectively arranged, a gas flow rate and wind speed sufficient to cool the motor 4 can be obtained. Depending on the electric blower, there are many cases where the effective arrangement is impossible. Also, in regions where the commercial frequency of electricity is high, the rotational speed of the motor is large, the power consumption is large, and the motor heat is large. Further, when the rotational speed is increased with an inverter or the like for the purpose of increasing the air volume, the heat generation of the motor increases. In such a case, the fan 22 of the present invention is more effective.

  The case storage type blower of the present invention is suitably used in a gas circulation purification device that creates a high purity inert gas atmosphere. When the present invention is used in a gas circulation purification apparatus, the purity of the circulation gas is improved, and the gas circulation purification apparatus is reduced in size, has a long service life, and is low in price. Furthermore, it has become easy to increase the rotational speed of the motor of the electric blower. Also, it can be easily installed in a clean room.

  A case housing type blower having the structure of FIG. 4 was produced. The electric blower is a side channel blower (motor maximum output 0.6 kW (50 Hz), 0.85 kW (60 Hz), discharge pressure 10.5 kPa (50 Hz), 13.1 kPa (60 Hz), maximum air volume 139 cubic meters / hour (50 Hz) 170 cubic meters / hour (60 Hz)). The blower motor is attached with a cooling fan attached to the rotating shaft of the motor on the opposite side of the blower mechanism, and is structured to rotate in accordance with the rotation of the motor to cool the motor. When the outer shape of the blower was approximated by a cylindrical shape, the approximate dimensions were a diameter of 302 mm and a length of 293 mm (including a cooling fan part). The case (1 in FIG. 1) is cylindrical and has a diameter of 320 mm and a height of 360 mm. Using this case storage type blower, a gas circulation purification apparatus having the configuration shown in FIG. 3 except that the blower is a case storage type blower of the present invention was manufactured. The molecular sieve used 7 kg of model No. 13X manufactured by Axense, and the oxygen adsorbent used 4 kg of a sulfur-resistant Ni catalyst manufactured by JGC Chemicals. The cooling tower (16 in FIG. 3) has a shell-and-tube structure in which 12 stainless tubes having an outer diameter of 9.53 mm, an inner diameter of 7.53 mm, and a length of 250 mm are used as a gas passage. When the molecular sieve adsorbs moisture to saturation or when the Ni catalyst combines with oxygen, a heater is installed in the purification tower (13 in FIG. 3) for the purpose of dehydration and reduction treatment under heating. Although not shown in the figure.

  The gas circulation purification apparatus having the case storage type blower of the present invention was connected to a stainless steel box having an internal volume of 560 liters. The SUS box is equipped with a thin film aluminum oxide sensor dew point meter and a zirconia electromotive force type oxygen concentration meter. The rotational speed of the motor (4 in FIG. 4) was adjusted by adjusting the frequency with an inverter. The temperature inside the motor was measured by the resistance method of JIS C 4203 standard. In addition, the insulation type of the used motor is B class insulation, and the limit of a temperature rise is 80 degreeC. After evacuating the inside of the SUS box, argon gas was introduced and the entire system was brought to 1 atmosphere of high-purity argon gas, and then the gas circulation purification apparatus was started. The relationship among the frequency of the supplied power, the gas pressure at the outlet of the case-contained blower (3 in FIG. 4), the circulating gas flow rate, and the internal temperature rise (rise range) of the motor was as follows. At 40 Hz, 6 kPa, 50 cubic meters / hour, 44 ° C., 50 Hz, 9.8 kPa, 61 cubic meters / hour, 53 ° C., 60 Hz, 10.2 kPa, 70 cubic meters / hour, 67 ° C. By changing the frequency, the amount of circulating gas can be increased, and the motor temperature remains within the limits. By passing through the cooling tower (16 in FIG. 3), the temperature of the gas flowing into the glove box was a problem gas temperature of 29 ° C. or less. The oxygen concentration was 850 ppm after replacement with argon gas, but decreased to 1 ppm in 3 minutes after the gas circulation purification apparatus was started. The water concentration was 520 ppm after replacement with argon gas. Moisture concentration was greatly affected by adsorbed water in the gas circulation system including the inside of the SUS box, and it took time to drop below the oxygen concentration. However, after about 6 hours, it became -76 ° C (1 ppm), and good gas purification. Showed ability.

Comparative Example 1

  The cooling fan (22 in FIG. 4) was removed from the motor of the example (4 in FIG. 4) and then stored in the case (1 in FIG. 4), and the same test as in the example was performed. That is, the relationship between the frequency of the supplied power, the gas pressure at the outlet of the case-housing fan (3 in FIG. 4), the circulating gas flow rate, and the internal temperature rise (rise range) of the motor was as follows. At 40 Hz, 6.3 kPa, 50 cubic meters / hour, 49 ° C., 50 Hz, 9.7 kPa, 60 cubic meters / hour, 63 ° C., 60 Hz, 10 kPa, 73 cubic meters / hour, 82 ° C. Thus, the temperature rise inside the motor was larger than in the example, and exceeded the limit of the insulation heat resistance standard at 60 Hz. The gas temperature flowing into the SUS box was 32 ° C. or lower. Although the temperature was slightly higher than that of the example, the gas temperature was not particularly problematic. The gas purification capacity was almost the same as in the examples, and there was no problem.

  It is a schematic diagram of the case storage type blower of the present invention. 1 is a case, 2 and 3 are gas inlets and outlets, 4 is an electric motor (motor) of an electric blower, 5 is a blower mechanism portion, and 6 is a rotating shaft connecting the motor and the blower mechanism. 7 and 8 are gas inlets and outlets of the blower mechanism.   It is a schematic diagram explaining Example 2 which provided the gas cooling mechanism 9 inside the case of the case storage type air blower of this invention. Reference numerals 10 and 11 denote an inlet side and an outlet side of the cooling water.   The gas circulation purification apparatus of the comparative example 1 was shown. 19 is a gas circulation purification device, 20 is an inlet for gas entering the device, and 21 is an outlet for purified gas delivered from the device. The electric blower of this comparative example is equipped with a small fan 12 that cools the motor. Reference numeral 16 denotes a cooling mechanism that cools the gas whose temperature has been increased by the blower mechanism, and reference numerals 17 and 18 denote an inlet side and an outlet side of the cooling water. 13 is a purification tower, 14 is a moisture adsorbent, and 15 is an oxygen adsorbent.   It is a schematic diagram of the case storage type air blower used for the Example. Although the basic configuration is the same as in FIG. 1, a fan 22 for cooling the motor is attached to the rotating shaft of the motor 4 in this figure.

Explanation of symbols

1 Case, 2 Gas inlet, 3 Gas outlet, 4 Electric motor (motor), 5 Blower mechanism, 6 Rotating shaft, 7 Blower mechanism gas inlet, 8 Blower mechanism gas outlet, 9 Gas cooling mechanism, 10 Cooling water Inlet, 11 Cooling water outlet, 12 Motor cooling fan, 13 Gas purification tower, 14 Moisture adsorbent, 15 Oxygen adsorbent, 16 Cooling tower, 17 Cooling water inlet, 18 Cooling water outlet, 19 Gas circulation purification Equipment, 20 Gas inlet, 21 Gas outlet, 22 Cooling fan, 23 Motor, 24 Rotary shaft seal

Claims (6)

The electric blower is housed in a case with good airtightness, the case is provided with a gas inlet and outlet, and after the gas that has entered from the inlet spreads into the case, it enters the air blower mechanism portion of the electric blower, The gas blown out and sent out from the blower mechanism portion is sent out from the case outlet without being discharged into the case by connecting the gas outlet of the blower mechanism and the gas outlet of the case. A gas circulation purification apparatus characterized by using a case-enclosed blower having a good sealing property and having a structure and a fan for cooling the electric fan of the electric blower . The electric blower is housed in a case with good airtightness, and the case is provided with a gas inlet and outlet, and the gas entering from the inlet is connected to the inlet of the case and the inlet of the blowing mechanism portion of the electric blower. The structure that enters the air blowing mechanism part without being discharged into the case, is blown by the air blowing mechanism, and is sent from the outlet of the case after the gas sent out from the air blowing mechanism part spreads in the case A gas circulation purification apparatus characterized by using a case-enclosed blower with good airtightness , wherein a fan for cooling the electric fan of the electric blower is provided in the case. The gas circulation purification apparatus according to claim 1 or 2 , wherein a mechanism for cooling the gas is provided in the case . The gas circulation purification apparatus according to claim 1, wherein the gas is an inert gas. The motor of the electric blower has a structure in which a cooling fan attached to the rotating shaft of the electric motor is attached to the opposite side of the electric blower mechanism, and the electric fan is rotated according to the rotation of the electric motor to cool the electric motor. The gas circulation purification apparatus according to claim 1, 2, 3, or 4. A fan arranged in the case for cooling the electric motor is driven to rotate by a fan electric motor installed outside the case, and a rotating shaft connecting the fan electric motor and the fan is connected to the case. The gas circulation purification apparatus according to claim 1, 2, 3 or 4, wherein the gas circulation purification apparatus is arranged by being sealed by a rotary seal mechanism.

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