JP4883394B2 - Case storage type blower and gas circulation purification device - 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 gas temperature causes an increase in the temperature of the molecular sieve, leading to deterioration of moisture adsorption performance, so it is necessary to cool the inert gas more strictly.

  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. Means have been taken, such as providing a double-use seal before making it practical. 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.

  The present invention is a case storage type blower that aims to solve all the problems related to the electric blower. Furthermore, it is the gas circulation refinement | purification apparatus using this case accommodation type air blower.

  That is, the present invention accommodates an electric blower used in a system that is apt to be mixed with the atmosphere in a case with good airtightness, and the case is provided with a gas inlet and outlet, and the gas from the inlet controls the motor of the electric blower. After flowing so as to cool, the air enters into the air blowing mechanism part of the electric blower, the air blown by the air blowing mechanism, and the gas sent out from the air blowing mechanism part is connected to the gas outlet of the air blowing mechanism and the gas outlet of the case Thus, the case-accommodating blower is structured to be delivered from the outlet of the case without being discharged into the case. Or, the configuration in which the gas inlet / outlet is reversed, that is, the gas entering from the inlet is not released into the case by connecting the inlet of the case and the inlet of the blowing mechanism portion of the electric blower. Case housing with a structure in which the gas that enters the air blowing mechanism, is blown by the air blowing mechanism, and flows out from the air blowing mechanism flows to cool the motor of the electric blower, and then is sent out from the outlet of the case Type 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. 1 is a gas inlet, and 3 in FIG. 1 is a gas outlet. The gas that has entered from the inlet cools the motor 4 of the electric blower, enters the inlet 7 of the blower mechanism 5, is pressurized and blown, and is sent 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. 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, the present invention does not require a small fan for cooling the motor. The gas flowing from the case inlet 2 to the inlet 7 of the blower mechanism cools the motor 4. In order to obtain a configuration in which this cooling effect is effective, the case inlet 2, the motor 4, and the gas inlet 7 of the blower mechanism 5 need only be arranged in this order in the space. The flow rate of gas per unit time is about 20 cubic meters / hour to about 120 cubic meters / hour in a commercially available gas circulation purification apparatus, which is a flow rate sufficient to cool the motor, and the gas flow is always turbulent. . For this reason, strict conditions are not necessary for the arrangement of the case inlet 2, the motor 4, and the gas inlet 7 of the blower mechanism 5, and a structure in which gas flows around the motor 4 and cools the motor 4 is sufficient. . Furthermore, in order to make the cooling effect effective, the case 1 is preferably made compact. That is, it is necessary to devise so that the gas that has entered from the case inlet 2 continues to flow inside the case without being stagnated or continuously stirred. Specifically, the inner volume of the case (1 in FIG. 1) is a size within 1.2 to 3 times the volume of the electric blower calculated by the outer dimensions of the electric blower (4 to 8 in FIG. 1). Good to do. As is apparent from the above configuration, the case storage type blower of the present invention does not disturb 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.

  FIG. 2 illustrates a further development of the present invention. 1 to 7 in the 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 does not have to be exact, and it is sufficient if the motor and the cooling mechanism are arranged in the passage of the gas flowing in the case between the entrance and exit of the case and the entrance and exit of the blower mechanism. It is.

  The flow rate of gas per unit time must be sufficient to cool the motor. As described above, in a commercially available gas circulation purification apparatus, the flow rate is about 20 cubic meters / hour to about 120 cubic meters / hour, which is a flow rate sufficient to cool the motor. When the rotational speed of the electric motor is high, the power consumption is large and the motor generates a large amount of heat, but the gas flow rate is also increased at the same time and sufficient cooling is possible. On the other hand, when the gas flow rate is reduced by reducing the rotation speed with an inverter or the like, the motor generates less heat, and the motor can be sufficiently cooled even with a small gas flow rate.

  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. In addition, it can be easily installed in a clean room.

  A case housing type blower having the structure of FIG. 1 was produced. The electric blower used was a side channel blower (motor maximum output 0.4 kW, discharge pressure 13 kPa, maximum air volume 70 cubic meters / hour). External dimensions of the blower were 250 mm in diameter and 23 mm in length with the motor cooling fan removed from a commercially available product. The case (1 in FIG. 1) is cylindrical and has a diameter of 300 mm and a height of 270 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 France AXENS Co., Ltd., and the oxygen adsorbent used 4 kg of sulfur-resistant Ni catalyst manufactured by JGC Chemical Co., Ltd. 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 glove box having an internal volume of 720 liters. The glove box is equipped with a thin film aluminum oxide sensor dew point meter and a zirconia electromotive force type oxygen concentration meter. After the atmosphere in the glove box was replaced with argon gas, the gas circulation purification apparatus was started. The circulating gas flow rate was 48 cubic meters / hour, and the gas temperature flowing into the glove box was a problem gas temperature of 29 ° C. The oxygen concentration decreased to 1 ppm in 4 minutes after the gas circulation purification apparatus was started up, became 0.3 ppm after 2 days, and became 0.1 ppm after 1 week. The moisture concentration is greatly influenced by the adsorbed water in the gas circulation system including the inside of the glove box, and the dew point lowering rate is slow, and there are variations from measurement day to day, but on average, it becomes −76 ° C. (1 ppm) after 2 days. It became -86 degreeC after a week. Although the gas circulation purification apparatus was continuously operated for one year in a state where it was connected to the glove box, the gas circulation purification apparatus showed good durability without problems and troubles.

Comparative Example 1

  A combination of the same glove box and gas circulation purification apparatus as in the embodiment, but instead of the case storage type blower of the present invention, a three-leaf roots type submersible blower BWF4015 type (direct motor, motor maximum output 1. 5 kW, discharge pressure 10 kPa, power consumption 0.54 kW, air volume 71 cubic meters / hour) were used. The blower was developed for use in water, but can also be used in the air by cooling the motor with an air cooling fan (propeller fan). However, the air blown toward the motor by the fan flowed not only inside the gas circulation purifier but also outside the apparatus, disturbing the outside atmosphere. Similarly to the example, the atmosphere in the glove box was replaced with argon gas, and then the gas circulation purification device was started. The circulation gas flow rate was about 60 cubic meters / hour, and the gas temperature flowing into the glove box was slightly high at 35 ° C. However, as long as cooling water of about 20 ° C was allowed to flow through the cooling tower, the gas temperature was maintained at 35 ° C. There was no problem gas temperature. The oxygen concentration decreased to 1.3 ppm in 4 minutes after the gas circulation purification apparatus was started up and became 0.8 ppm after 2 days, but no subsequent decrease in oxygen concentration was observed. Even after one week, it was 0.8 ppm. As described above, the moisture concentration is greatly influenced by adsorbed water and has a slow dew point reduction rate, and varies from measurement day to day. On average, the water concentration becomes −76 ° C. (1 ppm) after 2 days, and −80 ° C. after 1 week. However, it was not as low as the dew point as in the previous examples, and this -80 ° C state was continued. There was no problem or trouble during 10 months of continuous operation in this state, but after 10 months, the oxygen concentration and dew point increased. As a result of inspection after continuous operation for 1 year, oil seal wear was found. .

  A case storage type blower having the structure of FIG. 2 was produced. As the electric blower, the same side channel blower as in Example 1 was used, and a gas cooling mechanism (9, 10, 11 in FIG. 2) having a fin tube heat exchanger structure was incorporated in the case. The case size is 300 mm in diameter and 350 mm in height. Although the height was slightly larger than in the case of the first embodiment, the cooling tower could be omitted in the gas circulation purification apparatus using this case-accommodating blower, so that the overall apparatus size could be made more compact than in the first embodiment. did it.

  The case storage type blower was incorporated in the same gas circulation purification apparatus as in Example 1, connected to a glove box, gas circulation purification operation was performed, and the same evaluation was performed. The circulation gas flow rate was 47 cubic meters / hour, and the gas temperature flowing into the glove box was 31 ° C., which was no problem. The oxygen concentration decreased to 0.8 ppm in 4 minutes after starting the gas circulation purification apparatus, became 0.3 ppm after 2 days, and became 0.1 ppm after 1 week. The moisture concentration is greatly influenced by the adsorbed water in the gas circulation system including the inside of the glove box, and the dew point lowering rate is slow and varies from measurement day to day. On average, it becomes −78 ° C. (1 ppm) after 2 days. It became -88 degreeC after a week. Furthermore, although continuous operation was conducted for one year, it showed good durability without problems and troubles.

  In the gas circulation purification apparatuses of Example 1 and Comparative Example 1, using the cooling tower, the argon gas temperatures exiting the gas circulation purification apparatus and flowing into the glove box were 29 ° C. and 35 ° C., respectively, as described above. In each case, the gas temperatures when the cooling water was stopped were 39 ° C. and 51 ° C. In Example 2, the gas temperature could be set to 31 ° C. by the gas cooling mechanism installed in the case of the case storage type blower, and the effectiveness of the cooling mechanism was proved.

  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.

Claims (6)

An electric blower used in a gas circulation purification device that dislikes air mixing is housed in a case with good airtightness, and a gas inlet and outlet are provided in the case so that the gas entering from the inlet cools the motor of the electric blower. The gas blown into the blower mechanism part of the electric blower after flowing into the air, blown by the blower mechanism, and sent out from the blower mechanism part by connecting the gas outlet of the blower mechanism and the gas outlet of the case A case-accommodating blower structured to be delivered from the outlet of the case without being discharged into the case.   An electric blower used in a system that does not want to be mixed in the atmosphere is housed in a case with good airtightness. The case has a gas inlet and outlet, and the gas entering from the inlet is the inlet of the case and the blowing mechanism of the electric blower By connecting the inlets of the portions, the gas enters the air blowing mechanism portion without being released into the case, is blown by the air blowing mechanism, and the gas sent from the air blowing mechanism portion cools the motor of the electric blower. A case-accommodating blower having a structure that is sent out from the outlet of the case after flowing in such a manner.   The case storage type blower according to claim 1 or 2, wherein a mechanism for cooling the gas is provided in the case. 請 Motomeko 2 or claim 3 in case receiving-type blower system dislike contamination of the atmosphere is you characterized by a gas circulation purifier.   The case-housing fan according to claim 1, 2, 3, or 4, wherein the gas is an inert gas.   A gas circulation purification apparatus using the case housing type blower according to claim 1, 2, 3, 4, or 5.

Images