JP5518815B2 - Fan filter unit fan structure - Google Patents

Description

  The present invention relates to a fan structure of a fan filter unit (FFU) that supplies clean air into a clean room.

  Conventionally, in a clean room, as described in JP-A-2000-205621, page 3, item 4, line 23 and below, “Since various chemicals are used in a clean room, they can be affected by these chemicals. It is preferable to be formed of a metal (for example, aluminum or stainless steel) member rather than a resinous material. ”The fan is made of aluminum, stainless steel, a plated steel plate, a steel plate coated after processing, etc. It is formed by processing and assembling a metal plate having a thickness of about 0.5 to 1.0 mm.

JP 2000-205621 A

  Further, as shown in FIGS. 4 to 5, the conventional fan has a plate-like main support member A having a circular shape in a plan view with a concave portion at the center, the same outer diameter as the main support member A, and the main support member on the inner peripheral side An annular sub-support member B that is drawn and bent in the same direction as the concave portion, and five blade members C that are vertically arranged in an oblique radial manner across the main and sub-support members A and B at equal intervals. The motor shaft joining boss D is formed separately, the blade member C is aligned between the main / sub support members A and B, and the claw piece c provided on the blade member C is attached to both the support members A and B. Since the boss D for bonding is fixed to the center of the concave portion of the main support member A and assembled by joining and assembling, a large number of skillful manufacturing processes are required, and press molding, The cost of the mold for assembly is, for example, 10,000,000 yen to 20,000,000 yen when the outer shape is 390φ Thus, there is a problem that the manufacturing cost of the fan is high due to the high price.

  In addition, in order to prevent the occurrence of vibration by rotating the fan stably, it is important that the fan's weight balance is not biased. However, in the case of a sheet metal fan assembled as described above, distortion during press and welding, It is normal for the weight balance to vary due to misalignment during joining and assembly. To correct this unbalance, the position and amount of weight excursion are measured by rotating each fan on a balancing machine. However, since a counterbalance process is required to fix the counterbalance weight on the opposite side and remove the unbalance, there is a problem that this labor is also one of the causes of high costs.

In addition, a fan filter unit incorporating a heavy fan made of metal vibrates due to the weight of the fan during transportation, and the vibration causes distortion in each member, causing a new unbalanced state and requiring rebalancing. There is a problem that there is.
The impact that is synergistic with the weight of the fan often damages the bearing that supports the motor rotation shaft, and there is a problem in that the vibration during operation increases or abnormal noise is generated from the motor.

Also, the heavier the fan, the longer the startup time to the specified speed, so use a large motor with a larger torque than required for normal operation to reach the specified speed in a short time. There is a problem that it is necessary.
In addition, a rotating body such as a fan has a problem that vibration and noise are likely to occur as the centrifugal force increases, and in order to solve this, it is realistic to correct the dynamic balance or reduce the weight. As a countermeasure, a new problem of rotational speed (destructive rotation speed) arises for easy weight reduction of the fan.

  In addition, it is desired to reduce the weight as much as possible in order to install a large number of fan filter units on the ceiling of a clean room.

The present invention is a fan to supply clean air into the clean room, a foam was kept fine particulate beads of polystyrene low foaming rate of 10-30%, the silo was applied for a certain period of time the respective expanded beads ripening by after stabilizing the internal pressure and formed mold was filled in a hex-bromo-cyclo-dodecane (HBCDD) added to the mold for the fan molding kneaded self-extinguishing highly flame retardant aid such as Thus, such a problem is solved by forming a fan having a thickness and flame retardancy close to those of sheet metal and having high strength like an injection molded plastic product .

  The fan molded with the polystyrene foam of the present invention can reduce the cost of the mold to 1/10 or less compared with the cost of the press mold and assembly mold required for sheet metal products, so that the initial investment cost can be kept extremely low. In addition, the use of a styrofoam material that is much cheaper than a metal plate material has the effect that the manufacturing cost of the fan can be drastically reduced.

  The fan can be molded as a single piece or a two-part body that can be easily joined by foaming of polystyrene foam, so that the production efficiency can be greatly improved. Moreover, since the absolute weight is extremely small, for example, even if there is a deviation in the weight balance, the rotation will not be adversely affected. Even if this occurs, it remains in a range where there is no influence, so that it is possible to eliminate the trouble of adjusting the balance of the fan.

  By reducing the weight of the fan, vibration during transportation of the fan filter unit can be reduced, preventing the occurrence of balance loss due to vibration distortion, and avoiding damage to the bearing that supports the motor shaft. The effect of being able to be produced.

  Since the fan is reduced in weight, the drive speed can be reached in a short time even if the size of the drive motor is reduced, so that the equipment cost and the operating cost can be reduced.

  Since the fan is made of foamed polystyrene having high sound absorption performance, the effect of reducing wind noise and vibration from the motor can be obtained without a special vibration isolation structure. In addition, since the fan is coated with electroless nickel plating, the chemical resistance, oil resistance, heat resistance and strength, which are weak points of expanded polystyrene products, are greatly improved, and dust generation caused by damaged expanded polystyrene is prevented and generated from expanded polystyrene. As a result, it is possible to prevent the gas from being scattered and to be used for many years as in the case of conventional sheet metal.

Longitudinal side view showing fan molding Plan view of fan with electroless nickel plating Longitudinal side view showing the state assembled to the fan filter unit Longitudinal side view of the conventional sheet metal fan before assembly Same as above, assembled plan view

1 is a fan 1a is a main support member 1b is a sub-support member 1c is a blade member 1d is a motor shaft joining boss 2 is a mold 3 is electroless nickel plating 4 is a module 5 is a motor 5a is a rotating shaft of a motor 6 is a screw 7 Is the outer box 8 is the filter unit

In the present invention, the fan of the fan filter unit is formed of a foamed polystyrene material having a foaming rate of 10 to 30%, and the entire surface of the fan is coated with electroless nickel plating.
Styrofoam molding makes the cost and material cost of fan production significantly lower than those of conventional sheet metal, and eliminates the need for balance adjustment through precision integral molding that does not require assembly. Prevents the occurrence of excessive distortion, enables operation with a smaller motor than before, and has sufficient strength for continuous operation and chemical resistance, oil resistance, and heat resistance equivalent to a sheet metal fan. It was made to be able to.

  FIG. 1 to FIG. 3 show an embodiment, and polystyrene, which is a material of expanded polystyrene, is foamed with a hydrocarbon gas such as butane / pentane, and the hydrocarbon gas is absorbed by fine polystyrene polystyrene beads having a diameter of about 1 mm. This is a polystyrene foam (expanded polystyrene) that applies high-temperature steam of 100 ° C or higher, which exceeds the heat-resistant temperature of 80 to 90 ° C, to soften and melt the resin and foam it by applying pressure to fuse the expanded beads together. , EPS), and the fan 1 is integrally molded in the mold 2.

  More specifically, polystyrene beads are put into a foaming machine as preliminary foaming, and heated with steam while stirring to expand the polystyrene beads. In this process, the foaming rate is controlled so as to become a set value of 10 to 30% (volume ratio 1.1 times to 1.3 times), and then transferred to an aging silo for about 8 to 24 hours. Is used to stabilize the pressure in the particles, and after that, polystyrene beads are filled into a mold 2 for molding a fan and secondarily foamed by steam, and at the same time, the beads 1 are fused together to mold the fan 1. is there. In addition, a flame retardant of a polystyrene foam may be increased by kneading and adding a flame retardant aid having high self-extinguishing properties such as hexa-bromo-cyclo-dodecane (HBCDD) in advance to the material polystyrene.

The mold 2 is constructed so that the main support member 1a, the sub support member 1b, the blade member 1c and the motor shaft joining boss 1d constituting the fan 1 are integrally molded. The completed fan 1 is obtained by integral molding that is not required.
The main support member 1a and the boss 1d for motor shaft joining, the sub-support member 1b and the blade member 1c are molded in a two-part divided body, and these are joined using means such as adhesion. Sometimes you want to. In any case, the assembling work is very easy as compared with the case of sheet metal, and no press or welding work is required, so that no distortion occurs.

  By limiting the foaming ratio of polystyrene beads to 10 to 30%, it is possible to obtain a fan 1 that can be very strong like an injection-molded plastic product, and that has high dimensional stability and excellent molding accuracy. it can. Since the fan 1, particularly the blade member 1 c, can be molded with a thickness close to that of sheet metal, the fan 1 that can make use of the conventional design concept of aerodynamic characteristics can be obtained. If the foaming ratio is lower than 10%, the fusion force between the polystyrene beads is weakened and the molding accuracy is lowered, and if it is higher than 30%, the minimum thickness of the processed thickness is increased and the thickness of the blade member on the air flow side is increased. There is a possibility that the shape cannot be reproduced. In addition, the mold 2 which does not require high pressure resistance because of low foaming can be manufactured at a very low cost in terms of material and strength.

  In addition, since the specific gravity of polystyrene, which is a raw material of polystyrene foam, is 1.05, the weight of the polystyrene foam fan 1 molded at a foaming rate of 10 to 30% is about 8 minutes compared to a stainless steel (alloy) fan. The weight is remarkably reduced to 1 to 1/10 of that of aluminum and about 1/3 to 3.5 of aluminum (alloy).

  Next, the removed fan 1 is put in an electroless plating tank and electroless nickel plating 3 having a thickness of 5 to 20 μm is applied. Electroless plating can be applied to non-conductive materials such as polystyrene foam with good adhesion by chemical plating in which electron ions released by oxidation of the reducing agent are transferred to metal ions to form a metal film. Electroless nickel plating with Ni-P (nickel-phosphorus) alloy has a very high film thickness accuracy (± 5%) to form a film with a uniform film thickness even in complex shapes such as the fan 1, so it is integrated. The surface hardness can be increased and the corrosion resistance can be improved without impairing the weight balance of the fan 1 obtained. In addition, since electroless nickel plating has high ductility, it is excellent in followability and resilience against minute deformation due to resistance during blowing. This electroless nickel plating improves the chemical resistance, oil resistance, etc., which are weak points of expanded polystyrene, prevents dust generation due to damage to the expanded polystyrene, and confines the gas generated from the expanded polystyrene and blows it into the clean room. Can be prevented. Furthermore, by improving the heat resistance, it is possible to clear the flame retardant values required under the Fire Service Law.

  The fan 1 manufactured as described above is fitted to the shaft 5a of the motor 5 in which the motor shaft joining boss D is fixed to the module 4, and fixed with screws 6. The module 4 is attached to the outer box to form the fan filter unit 6. Since the fan 1 is extremely lightweight, the start-up time up to the specified rotational speed can be shortened even if the motor 5 is smaller than the conventional one. Further, the weight reduction of the fan 1 reduces the occurrence of vibration during transportation, which prevents the occurrence of imbalance due to distortion, etc., and damages to the motor bearings. Thus, wind noise and vibration from the motor can be attenuated without providing a special vibration isolation structure.

  The styrene foam fan of the present invention is widely used as a fan for a new fan filter unit or as a replacement for an existing fan.

Claims (1)

A fan to supply clean air into the clean room, foam and that kept in the low expansion ratio of the finely divided beads 10-30% of polystyrene, the internal pressure by silo ripening multiplied by the predetermined time the respective expanded beads after stable, sheet-metal by forming mold is filled the hex-bromo-cyclo-dodecane (HBCDD) added to the mold for the fan molding kneaded self-extinguishing highly flame retardant aid such as The fan structure of the fan filter unit is characterized by forming a fan having a plate thickness and flame retardancy close to, and having a high strength like an injection molded plastic product .

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