JP4281957B2 - Push-pull ventilator - Google Patents

Description

  The present invention relates to a push-pull type ventilator, and more particularly to a push-pull type ventilator having an improved uniform air flow blowing mechanism.

  In recent years, a push-pull type ventilator that combines a push hood with a uniform air flow blow-out mechanism and a pull hood with a suction exhaust mechanism has been used as a local exhaust device for dust generation sites such as welding and polishing, and organic solvents such as painting and cleaning. It has come to be used at work sites that use it. In order to operate these push-pull type ventilation devices effectively, high uniformity is required for the air flow from the push hood. Here, uniformity or uniform flow means a state in which the magnitude of the flow velocity is substantially constant throughout the cross section when viewed in a cross section perpendicular to the flow. According to “Factory Ventilation” published by the Society for Air Conditioning and Sanitary Engineering, published in 1982, it is suggested that the variation in velocity distribution should be within ± 20% of the average value.

  The applicant has proposed Patent Document 1 as a push hood that meets these required characteristics. This push hood has the problem that it is difficult to obtain a uniform flow when the opening surface is not a symmetrical shape such as a square shape when there is only one fan that is a source of blown air flow. Have.

JP 2001-289500 A

  An object of the present invention is to provide a push-pull type ventilator having a push hood capable of providing a uniform flow with a single fan even when the structure is simple and has a rectangular opening surface.

The present invention provides a push-pull ventilation system that combines the Purufudo with push hoods and suction exhaust mechanism having a uniform air flow blow mechanism, as a push hood length ratio of the vertical-to-horizontal is 1: 1.1 the central portion with having a rectangular opening of 5 has one of the fans, mini front center portion of the fan, the area of the unit hole in 100 to 1000 mm ^2, porosity is at 15-80%, perforated It is characterized by using a push hood with a built-in fan , in which a perforated plate having a square shape equal to or smaller than the fan blade diameter and open on both sides and a rectifying member disposed thereafter is used. It is a push-pull type ventilation device.

  According to the present invention, it is possible to provide a push-pull type ventilator having a push hood excellent in energy saving at low cost.

The present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view showing a fan of a push hood used in the present invention and a perforated plate disposed immediately before the fan, and FIG. 2 is a front view thereof (a) and a right side view of the push hood corresponding thereto (b). It is.

The push hood used in the present invention has a rectangular shape in which a fan (a pressure ventilation fan, a spiral flow generating rotary impeller, an axial fan) 1 is arranged in the center, and a perforated plate 2 only in the center corresponding to the fan. Is placed so that both sides are open. The perforated plate 2 is the area of the unit hole or one of holes 100 to 1000 mm ^2, preferably 200～600Mm ^2, porosity 15 to 80% and preferably of 45 to 70%, conventionally It is called a perforated plate to distinguish it from a perforated plate having fine holes used as a part of the flow regulating member.

  This perforated plate is preferably a so-called punching metal in which a large-diameter circular hole is formed in a metal plate, but the shape of the hole can be appropriately changed such as a square or other polygons. Further, as long as the area of the unit hole and the hole area ratio satisfy the requirements of the present invention, for example, a metal or hard plastic net may be used. The perforated body is arranged only in the center part of the front face that directly receives the air flow from the fan, and both sides are opened. The portion where the perforated plate is arranged varies depending on the size of the fan (blade diameter) to be used, but substantially corresponds to the size of the fan, and is preferably somewhat smaller than the blade diameter. Although it is preferable that the upper and lower sides of the perforated plate be air-impermeable and attached to the main body as shown in FIG.

The length ratio of the rectangle of the main body is preferably about 1: 1.1-5.
On the rear side of the perforated plate, rectifying members 3 having a size corresponding to the size of the rectangular opening are arranged at intervals. The rectifying member 3 is preferably one in which the honeycomb plate 4, the porous plates 5, 5 ′, and the honeycomb plate 4 ′ are arranged in this order. The area of the unit honeycomb of the honeycomb plates 4 and 4 ′ is preferably about 10 to 50 mm ² , and the area of the unit holes of the porous plates 5 and 5 ′ is also preferably about 10 to 50 mm ² . Further, the porosity is preferably 90% or more. The rectangular opening surface referred to in the present invention may be the honeycomb plate 4 ′ itself or a separate opening structure. The first honeycomb plate 4 removes the swirling flow dispersed through or without the perforated plate 2 and adjusts the airflow to some extent, and adjusts the air velocity distribution by the next two porous plates 5 and 5 ′. The direction of the air flow is made constant by the honeycomb plate 4 ′.
The invention will now be illustrated by the examples.

Example 1 (reference example):
Push hood (rectifier having a rectangular shape with an opening size of 1200 mm x 600 mm), with a single fan (feather 35 cm) in the center, and a distance between the fan 1 and the rectifying member 3 of 208 mm (300 mm for the entire rectifying member) The member has a double honeycomb structure shown in FIG. 2b), and the wind velocity at the opening surface was measured during 50 Hz operation. The results are shown in FIG. Although a certain degree of improvement was achieved by greatly extending the distance between the fan 1 and the rectifying member 3 from the typical example (15 mm) of Patent Document 1, the difference in wind speed between the vicinity of the center and the others was not improved.

Example 2:
Next, a perforated plate made of stainless steel punching with a hole diameter of 25 mm ² (unit hole area: 490 mm ² ) and a pitch of 30 mm (aperture ratio 63%) (in FIG. 2, x = 450 mm, y = 380 mm, including a non-open portion) z = 470 mm) was attached between the fan and the rectifying member 3 as shown in FIG. 2 and FIG. FIG. 5 shows the wind speed distribution on the opening surface at that time. A considerable improvement was observed compared to Example 1.

Example 3:
Next, the opening surface wind speed distribution when y = 300 mm is shown in FIG. Further improvement was observed compared to Example 2.

Example 4:
Next, in Example 2, the opening surface wind speed distribution when x = 300 mm is shown in FIG. Further improvement was observed compared to Example 3.

Example 5:
In Example 2, the punching metal hole diameter was set to 15 mm (unit hole area 177 mm ² ) and the pitch was set to 20 mm (opening ratio 51%). The results are shown in FIG.

Example 6:
In Example 2, the punching metal hole diameter was set to 20 mm (unit hole area 314 mm ² ), the pitch was set to 30 mm (opening ratio 40%), and the same experiment was performed to obtain the opening surface wind speed distribution. The results are shown in FIG.

The perspective view which shows the fan and perforated board of a push hood used by this invention. The front view a of FIG. 1 and the right side view b of the push hood corresponding to it. The right view which shows another example of the push hood of this invention. The graph which shows the wind speed distribution of Example 1 (reference example). The graph which shows the wind speed distribution of Example 2. The graph which shows the wind speed distribution of Example 3. The graph which shows the wind speed distribution of Example 4. The graph which shows the wind speed distribution of Example 5. The graph which shows the wind speed distribution of Example 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fan 2 Perforated plate 3 Rectifying member 4,4 'Honeycomb plate 5,5' Perforated plate

Claims (2)

In a push-pull type ventilator that combines a push hood having a uniform air flow blowing mechanism and a pull hood having a suction / exhaust mechanism, the push hood has a rectangular length ratio of 1: 1. the central portion with having an opening having a single fan, the front center portion of the fan mini, at area 100 to 1000 mm ² of the unit hole, with porosity 15 to 80% perforated portion of the fan A push-pull type that uses a push hood with a built-in fan in which a perforated plate that is the same as or smaller than the diameter of the wing and is open on both sides, followed by a rectifying member Ventilation device.   The push-pull type ventilation device according to claim 1, wherein the rectifying member comprises a rectifying member in which a honeycomb plate, one or more porous plates and a honeycomb plate are arranged in this order.

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