JPH0332916Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an air blowing structure for a clean room that can correct the turbulence of airflow and form a laminar flow in a hydrodynamic sense.

[Conventional technology]

Laminar flow clean rooms and clean tunnels are well-known technologies for creating clean spaces.
In this specification, these clean spaces will be collectively referred to as clean rooms, but in the vertical laminar flow clean rooms known so far, the area of the HEPA filter is It blows out air uniformly toward the suction surface on the floor, which is substantially equivalent to Suction was considered to be an important element in forming laminar flow.

[Problem that the invention attempts to solve]

Conventional vertical laminar flow clean rooms have the following problems that cause turbulence in the flow. Conventional HEPA filters that form the blowout surface are usually made up of a continuous medium with a meandering surface, so from a microscopic perspective, the blowout speed varies at the peaks and valleys, which affects the flow. This will cause disturbance. Also, it can be used on large areas such as ceiling surfaces.
When installing a HEPA filter, use a small area
It is normal to form a filter surface by placing a large number of HEPA filter units next to each other, and in this case,
A frame (ceiling frame) with a large number of squares is used to support each HEPA filter unit, but since this frame is exposed to the air blowing surface, vortices occur in this frame part, resulting in a laminar flow. It causes disturbance. Furthermore, if there are lighting fixtures or various measuring instruments on the ceiling surface, they will also disturb the flow.

The present invention aims to correct the flow turbulence in such a conventional laminar flow clean room to effectively form a true laminar flow in a hydrodynamic sense.

[Means to solve problems]

The present invention is a clean room air filter in which a ventilation resistor layer is installed on the side of the air blowing surface of a filter stretched in a plane, with a predetermined distance from the air blowing surface and substantially parallel to the air blowing surface. In a blowout structure, the ventilation resistor layer is made of mesh, cloth, foamed resin membranes, or similar porous membranes in which countless small pores are evenly formed from a material with a width of 1 mm or less in the planar direction. This porous film body is stretched over a frame in multiple layers substantially parallel to each other at a predetermined distance to form a framed multi-film unit, and the framed multi-film units are arranged in a plane with each other. The present invention provides a laminar flow formation structure for a clean room formed by forming a ventilation resistor layer of a required area by adjoining the ventilation resistor layer.

Here, the porous membrane used as the ventilation resistor layer in the present invention has substantially regular small ventilation holes over its entire surface, such as nets, woven fabrics, knitted fabrics, and foamed resin membranes. Refers to a sheet-like or film-like membrane layer that is formed in countless numbers with a certain resistance (that is, evenly so that the ventilation resistance does not vary depending on the position). Do not use so-called punching boards. In the case of ordinary porous resin boards (punching boards) where the holes are formed at a pitch of 4 mm or more, a vortex (Karman flow) is formed on the back side of the board between the holes. laminar flow in the hydrodynamic sense cannot be formed. To be more precise, it is the width thickness in the plane direction of the material that exists between the holes that form the ventilation holes (in the case of mesh or cloth, it is the diameter of the wire, and in the case of foamed resin membranes, it is the three-dimensional skeletal structure). In order to prevent the formation of the Karman flow, it is necessary that the average thickness of the material having the . Generally, when a thick object such as a cylinder exists in a flow, the appearance of the flow behind the object is determined by the Reynolds number with the dimensions of the object as the representative length, and if the Reynolds number exceeds 40, the flow behind the object is It is known that turbulence occurs (Karman flow occurs), but the maximum design air velocity in a laminar flow clean room is approximately 0.45 m/sec, and in this case, the air flow between the holes forming the ventilation holes. The Reynolds number can be made 40 or less by reducing the width and thickness of the material present in the material to 1 mm or less. For example, when the average blowout flow velocity is 0.45m/sec, 1mmAq
If the porous membrane body is provided with the above-mentioned ventilation resistance, true laminar flow in a hydrodynamic sense can be formed. Examples of mesh bodies that satisfy these requirements include stainless steel wire mesh, polyester single fiber mesh, polypropylene single fiber mesh, nylon single fiber mesh, Teflon single fiber mesh, and glass fiber mesh.

In the present invention, a porous membrane that forms this hydrodynamic laminar flow is placed a predetermined distance away from the air blowing surface of the HEPA filter and substantially parallel to the filter surface. A ventilation resistor layer having the required area is formed by stretching multiple polyurethane membranes over a frame to form a frame-equipped multi-layer membrane unit, and by making these frame-equipped multi-layer membrane units adjacent to each other in a plane. be. In order to support this framed multi-film unit, a frame for stretching the filter is used, and it is removably supported on the frame of the filter via a support.

In this invention, since the framed multilayer units are adjacent to each other, the frame itself is also 0.5 mm thick so that the width of the adjacent joints does not exceed 1 mm.
It is best to use a thin plate with the following thickness. As such a thin plate, a stainless steel thin plate or a resin thin plate may be used. The frame has a side length of 0.5 to 2.0 m.
It is practical to use a rectangular one.

The present invention will be explained in detail below with reference to the embodiments shown in the drawings.

In FIG. 1, 1 and 2 indicate a vertical frame and a horizontal frame stretched horizontally on the ceiling surface, and the vertical frame 1 and horizontal frame 2 form many squares on the ceiling surface. A HEPA filter unit (not shown in Figure 1) is installed above each of the openings in the squares, and is large enough to close the openings.
The HEPA filter will be spread out over a flat area. In the present invention, a predetermined space is provided between the air outlet surface of the filter (in the case of the vertical laminar flow type example shown in the figure, below the filter) on the side of the air outlet surface of the filter, which is stretched across the plane. Install the ventilation resistor layer according to the following. This ventilation resistor layer is a framed multilayer unit 3.
formed by the adjacency of Reference numeral 4 indicates a hanging fitting for hanging the framed multi-film unit 3 onto the frame 1 or 2.

FIG. 2 shows the overall appearance of the framed multi-film unit 3 with the film portions cut away.
This embodiment shows a unit with a double membrane structure consisting of an outer membrane 5 and an inner membrane 6, in which the outer membrane 5 and the inner membrane 6 are stretched parallel to each other with a predetermined distance from a rectangular frame 7. It has been passed. Both the outer membrane 5 and the inner membrane 6 have a diameter of 1.
A mesh consisting of wire bodies of mm or less is used. Frame 7
is made of a thin stainless steel plate with a thickness of 0.5 mm or less, and the strip-shaped thin plate is bent inward at four points along the width direction to form a rectangular frame.
The four side surfaces of this frame are parallel to each other, so the opening in the frame has the same opening area on both the bottom and top surfaces.

FIG. 3 schematically shows a partial cross section of the double membrane unit in FIG. 2, and FIG. 4 shows A in FIG. 3.
This is an enlarged view of the section. As shown,
An inner frame 8 is used to extend the outer membrane 5 and the inner membrane 6 in parallel to the frame 7 at a predetermined interval. This inner frame 8 is a rectangular frame having an outer diameter approximately equal to the inner diameter of the frame 7, and by inserting it into the frame 7, the edges of the outer membrane 5 and the inner membrane 6 are fixed at the same time. It becomes a hold down. That is, the outer membrane 5 is stretched so as to cover the bottom opening of the frame 7, and its edge is rolled up from the upper edge of the frame 7 to the inside through the outside of the frame 7, and the peripheral edge 9 is stretched over the upper edge of the inner frame 8. At the same time as pressing down with the edge 10, the peripheral edge 12 of the inner membrane 6 is pressed down in the middle of the frame 7 by the lower edge 11 of the inner frame 8. Then, if necessary, the peripheral edges of the outer membrane 5 and inner membrane 6 held down by the inner frame 8 are bonded with an adhesive 13.
Fix by.

5 and 6 schematically show how to press the outer membrane 5 and the inner frame 8 when attaching the inner frame 8 to the frame 7. As shown in FIG. The outer membrane 5 is stretched over the bottom of the frame 8, and its peripheral edge 12 is extended to the outside of the inner frame 8, while, as shown in FIG. 9 to the outside of the frame 7 and wrap it past the upper edge of the frame 7 to the inside. Then, in this state, the inner frame 8 is inserted up to the middle part of the frame 7. Thereby, the outer membrane 5 and the inner membrane 6 can be stretched across the opening of the frame 7 in parallel with a constant interval.

Although the illustrated embodiment shows a double membrane structure consisting of an outer membrane 5 and an inner membrane 6, a triple membrane or more multilayer structure can be formed by using an additional inner frame.

In order to install the framed multi-membrane unit constructed in this way on the air outlet side from the HEPA filter in a clean room, each unit is placed adjacent to each other as shown in FIG. 1 so as to cover the required area. That is, a multilayer ventilation resistor layer is formed on the HEPA filter air blowing surface with each unit adjacent to each other substantially parallel to the air blowing surface at a predetermined distance from the air blowing surface of the HEPA filter. As mentioned above, the membrane of each layer has countless small pores evenly formed from a material with a width thickness (wire diameter in the case of a net) of 1 mm or less in the planar direction, so each layer allows the fluid to flow through the membrane body. A dynamic laminar flow can be formed, and since each layer is arranged in multiple layers with intervals, the rectification effect can be synergistically enhanced.

Therefore, the presence of a frame supporting the HEPA filter, the presence of lighting equipment, or
The turbulence of the blown air flow in a laminar flow clean room due to the structure of the HEPA filter media is corrected by the ventilation resistance body made of a multilayer film body according to the present invention, thereby creating a true hydrodynamic layer. Flow can be formed. The installation of this multilayer membrane is also structured as a multilayer membrane unit with a frame, so the work can be done extremely easily and neatly, and it can also be removed freely, making it possible to create a sophisticated laminar flow clean room with low equipment costs. It has the excellent effect of being able to form.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing an example of the air blowing structure for a clean room according to the present invention, FIG. 2 is a perspective view showing an example of a framed multilayer unit according to the present invention, and FIG. 3 is a schematic diagram of the unit shown in FIG. 2. 4 is an enlarged view of part A in FIG. 3, FIGS. 5 and 6 are exploded views of the framed multi-film unit of the present invention, and FIG. FIG. 6 shows the state in which the outer membrane is stretched over the frame. 1, 2... Frame for attaching the filter, 3... Multi-layer membrane unit with frame, 4... Hanging bracket, 5... Outer membrane, 6... Inner membrane, 7... Rectangular frame,
8...Inner frame.

Claims (1)

[Scope of utility model registration request] In an air blowing structure for a clean room, an air blowing resistor layer is installed on the side of the air blowing surface of a filter stretched in a plane, at a predetermined distance from the air blowing surface and substantially parallel to the air blowing surface. As the ventilation resistor layer, mesh, cloth, foamed resin membranes, or similar porous membranes in which countless small pores are evenly formed by a material having a width of 1 mm or less in the planar direction are used. using
This porous membrane body is stretched over a frame in multiple layers substantially parallel to each other at predetermined intervals to form a framed multi-film unit, and the framed multi-film units are arranged adjacent to each other in a plane. Therefore, the laminar flow formation structure of the clean room is formed by forming a ventilation resistor layer of the required area.