JPS62213630A - Ceiling structure for clean room - Google Patents

Abstract

PURPOSE:To prevent stained air from entering by a method wherein air pressure within a sealed and closed spacing formed by a ceiling frame is controlled by connecting a discharging pipe to an assembly beam, its terminal end is connected to a discharging pump to discharge the air within the sealed and closed spacing out of the room to keep the interior within the sealed and closed spacing at a value slightly lower than atmospheric pressure. CONSTITUTION:A discharging pump is driven, air within a sealed and closed spacing of a ceiling frame 5 is discharged out to keep air pressure within the sealed and closed spacing at a negative pressure of about -5mmAg or so, resulting in that a discharging flow flowing toward a discharging pipe 6 arranged at an assembly beam 3 is formed within the sealed and closed spacing and at the same time it generates a suction flow 9 directed into the sealed and closed spacing from a periphery of a clearance 13 due to the presence of a pressure difference across the system ceiling 1. Therefore, stained air and a part of clean air of the air to be supplied to the clean room which do not pass through a filter 4 but enter directly the clean room through the clearance 13 are sucked into the sealed and closed spacing with the suction slow 9 and then discharged out. As a result, it is possible to eliminate an entering of stained air into the clean room and positively prevent degree of cleanliness from decreasing.

Description

[Detailed description of the invention] The present invention relates to a ceiling structure for a clean room.

[Problems with Prior Art] Recent developments in the electronics industry and precision machinery industry have increasingly required precision, miniaturization, high quality, and high reliability. Therefore, in electronic component factories such as semiconductor manufacturing factories, film manufacturing factories, precision machinery factories, etc., the adhesion of small amounts of floating particles to products being manufactured poses a major problem. Therefore, in such factories, clean rooms are increasingly being installed in order to keep the entire factory or the parts where the most important work is performed in a clean state as necessary. A clean room is a building with environmental conditions as
A general term for a specially constructed room where air cleanliness is an important factor along with temperature, humidity, and air flow, and the number of extremely small particles floating in a certain amount of air is a problem. It was designed to supply clean air into the room and at the same time expel contaminated air from the room to the outside, so that a constant flow of clean air circulates within the room. In other words, a dust removal chamber and an air curtain are installed at the entrance to the room to prevent dust adhering to the human body and dust from the atmosphere from entering as much as possible, and the pressure is raised to a level slightly higher than atmospheric pressure, for example, 15 mmAq, using a blower or the like. Air, 0.1μm
Air is blown into the room through a high-performance filter (hereinafter referred to as II [! r' A filter) that can collect airborne dust particles up to a diameter of 1 to 2 mm
Maintain a moderately high pressure clean air flow. On the other hand, the contaminated air inside the room is drawn outside through ducts installed in the surrounding walls, floor, or ceiling, and clean air is circulated.

This will be explained below based on the drawings. FIG. 1 is a partially cutaway plan view of a system ceiling of a clean room according to an embodiment of the present invention, and FIG. 2 is a partial longitudinal sectional view thereof.

In the figure, the system ceiling l consists of a joining member 2 having a protrusion with openings for joining on two, three or four adjacent sides, and an assembly beam made of a hollow square bar with openings at both ends. 3 and 3 are sequentially joined by inserting the protruding part of the connecting member 2 into the opening end face of the assembly beam 3 and connecting the filter cloth to the ceiling frame 5, which is combined in the shape of a quadrilateral lattice door as a whole. The periphery of the filter body, which is made into a quadrilateral shape with a certain thickness by folding in the direction, is surrounded by a quadrilateral frame made of elongated thin plates made of a light material such as aluminum or plywood.
It is made into a panel by fixing it with adhesive etc.
The EPA filter 4 is placed on the ceiling frame 5 at its periphery as shown in FIG. It is made by caulking the gap with silicone rubber etc. and integrating it. Since the ceiling frame 5 is made by connecting the joining member 2 and the assembly beam 3 as described above, it can be made with various dimensions by changing the length of the assembly beam 3. Further, it is desirable that the joining member 2 and the assembly beam 3 be made of lightweight and highly durable materials. Furthermore, descriptions of facilities for dehumidification and constant temperature, electrical equipment, and equipment for supplying and extracting air necessary for a lean room will be omitted since they are not directly related to the present invention.

The system ceiling 1 described above is made to a predetermined size based on the scale of the clean room and is used by being fitted into a predetermined ceiling part, but the ceiling frame 5 connects the joint member 2 and the assembly beam 3. Since they are assembled together, it is inevitable that a slight gap I3 will be created at the joint. Therefore, these gaps 13 are caulked with silicone rubber, etc., but the number of joints increases in proportion to the size of the ceiling frame 5, and it is difficult to ensure completeness. There is a problem in that it is difficult to reliably prevent the entry of fine dust that accompanies the supplied air and leaks from gaps because it contains a large amount of floating dust.

[Object of the Invention] In view of the above, an object of the present invention is to provide a method for preventing leakage of contaminated air from gaps existing at joints in a system ceiling.

[Summary of the Invention] According to the present invention, the above object is to communicate the hollow portion between the assembly beam of the ceiling frame and the joining member, and to exhaust the air in the hollow chamber formed in communication with the ceiling frame. This is achieved by combining means.

[Embodiments of the Invention] As described above, FIGS. 1 and 2 are a partial plan view and a partial vertical sectional view of an application example of the present invention. The system ceiling l includes an assembly beam 3, which is a square bar with both ends open.
A hollow box-shaped joining member 2 having a protrusion having openings for joining on two, three or four adjacent faces, respectively, is connected to a corresponding assembly beam. The ceiling frame 5 is assembled by inserting it into the opening of 3 and connecting it in sequence, and the paneled II E
The PA filter 4 is placed on the frame of the ceiling frame 5 so that the space of the lattice door of the ceiling frame 5 is closed by the II EP A filter 4 as shown in FIG. The gaps between the mounting parts are caulked with silicone rubber, etc. to integrate them. By making the ceiling frame 5 in this way, the hollow parts of each component are communicated with each other inside the ceiling frame 5 and a kind of sealed space is formed. By connecting some of the assembly beams 3 to exhaust pipes 6 and connecting their ends to an exhaust pump (not shown), the air in the closed space provided by the ceiling frame 5 can be exhausted to the outside.

Part of the air supplied to the clean room (not shown) is
This is so-called contaminated air that contains a large amount of floating Mu dust, but on the supply side (
The air pressure (on the upstream side of the arrow in Figure 2) is slightly higher than atmospheric pressure (
+15 mmAq), and even after the II IE P A filter 4 is communicated (on the downstream side of the arrow in Fig. 2), the air pressure is slightly higher than atmospheric pressure (about +2 mmAq) and the air is blown into the clean room. Therefore, if there is a gap in the system ceiling 1, contaminated air may leak into the clean room (not shown) through the gap.

Therefore, if an exhaust pump (not shown) is driven to exhaust air from the sealed space of the ceiling frame 5 to the outside and maintain a negative pressure of about 5 mmAq compared to the air pressure in the sealed space, the air inside the sealed space of the ceiling frame 5 will be maintained at a negative pressure of about 5 mmAq. An exhaust flow shown by the arrow IO is formed that flows in the direction of the exhaust pipe 6 installed on the assembly beam 3 at a key point, and since there is a pressure difference between the inside and outside of the system ceiling l, the air flows from around the gap 13 into the sealed space. creating an inlet air flow 9 inward. Therefore, II E of the air supplied to the clean room
A portion of the contaminated air and clean air that does not pass through the PA filter 4 and directly enters the clean room through the gap 13 is sucked into the closed space by the intake air flow 9 and discharged to the outside. As a result, it is possible to prevent contaminated air from entering the clean room and to reliably prevent a decrease in cleanliness.

The arrangement and number of exhaust pipes 6 and the capacity of the exhaust pump are appropriately determined based on the size of the clean room, the dimensions of the system ceiling l, and the like.

[Effect of the invention] As explained above, the air pressure in the sealed space created by the ceiling frame, which is a component of the system ceiling, is connected to the assembly beam with an exhaust pipe, the end of which is connected to the exhaust pump, and the exhaust pump is driven to seal the space. By exhausting the air inside the space to the outside and maintaining the pressure inside the closed space slightly lower than atmospheric pressure, leaking contaminated air is sucked into the closed space by the force of the pressure difference and discharged to the outside, making it possible to maintain the inside of the clean room at a pressure slightly lower than atmospheric pressure. This has the effect of reliably preventing contaminated air that is about to leak into the air, and eliminating a drop in cleanliness.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view of a system ceiling of an embodiment of a clean room to which the present invention is applied, and FIG. 2 is a partial longitudinal sectional view thereof. 1 Niji stem ceiling, 2: Joint member, 3: Assembly beam, 4:
Check l1tiPA filter, 5: ceiling frame, 6: exhaust V,

Claims (1)

[Claims] A ceiling frame consisting of assembled beams made of hollow rods connected in a lattice shape is installed near the ceiling in the clean room, and a high-performance air filter is attached to this ceiling frame so as to close each lattice space to form a ceiling wall. In a clean room configured such that clean air is supplied into the clean room through an air filter in the ceiling wall, the hollow chambers in the assembly beams of the ceiling frame are communicated with each other, and the assembly beams are connected to the ceiling frame. A clean room ceiling structure characterized by combining a beam with a means for exhausting air inside a hollow room.