JP5057680B2 - Pressure control system - Google Patents

Description

  The present invention relates to a system for controlling pressure in a room.

In order to control the pressure in a given room, a pressure control system is provided. This pressure control system is used, for example, to monitor the operation of receiving LNG (liquefied natural gas) from a LNG ship (tanker for transporting LNG) landing on a pier in the coastal area to a huge tank in the coastal area. This is applied to control the pressure in the pier monitoring room (see FIG. 8) provided in the pier. This pier monitoring room is provided near the site where LNG acceptance work is performed. In addition, since various electrical equipment for monitoring LNG acceptance work is installed in the pier monitoring room, even if flammable gas flows out, the flammable gas that flows out does not flow into the pier monitoring room It is necessary to do so. Therefore, the pressure in the jetty monitoring room is always kept constant (usually atmospheric pressure + 6.5 mmH ₂ O) using a pressure control system. Generally, in a pressure control system that controls the pressure in the pier monitoring room, a certain amount of outside air is sent into the pier monitoring room from the inlet of the ventilation duct by a blower fan to pressurize the pier monitoring room. The pressure is kept constant.

In addition, it is generally known to attach a hood (for example, a windproof hood or a rain avoiding hood) to the air inlet of the vent hole duct. There are various documents regarding such a hood (for example, see Patent Documents 1 to 5).
Japanese Utility Model Publication No. 6-2048 Japanese Utility Model Publication No. 8-839 Japanese Patent Laid-Open No. 10-246477 Japanese Patent Laid-Open No. 11-182903 Japanese Patent Application Laid-Open No. 7-233988

  However, when wind blows from the outside toward the air inlet of the ventilation duct, a thermal trip phenomenon may occur in the blower fan. In particular, in the system that controls the indoor pressure in the pier monitoring room, the intake port of the ventilation duct is also provided in the coastal area like the pier monitoring room, so it is easily affected by the strong wind blowing between the sea and the land. . When the thermal trip phenomenon occurs, the blower fan motor becomes overcurrent, and the control device operates to stop the blower fan. Therefore, it becomes impossible to pressurize the jetty monitoring room, and the pressure in the jetty monitoring room cannot be kept constant. Further, in order to restore the blower fan that has stopped, it is necessary for the worker to go to the site to perform the restoration work, and it takes time and effort to restore the pressure control system.

  Furthermore, in the system that controls the indoor pressure in the jetty monitoring room, the wind blown into the intake port of the ventilation duct contains a large amount of moisture, so that the deterioration of the blower fan is accelerated. If a problem occurs in the driving of the blower fan, it becomes impossible to pressurize the pier monitoring room, and it becomes difficult to keep the pressure in the pier monitoring room constant.

  As described above, in the pressure control system, a thermal trip phenomenon occurs in the blower fan due to the influence of wind from the outside, and the indoor pressure may not be stably controlled.

  An object of this invention is to provide the system which can control the indoor pressure stably.

The pressure control system according to the present invention controls the indoor pressure to be maintained at a pressure higher than atmospheric pressure. The system includes a ventilation duct, a blower fan, and a duct hood. The ventilation duct communicates between the room and the external space. The blower fan is provided in order to send outside air from the external space into the room through the ventilation duct. The duct hood has a hollow shape, wraps around the intake port of the ventilation duct, and the lower side is opened by the ventilation port. The opening area of the ventilation hood of the duct hood is set larger than the opening area of the intake opening of the ventilation duct, and the passage area of the downstream passage located on the downstream side of the intake opening of the ventilation duct is equal to the ventilation duct. It is set smaller than the opening area of the intake port. The ventilation opening of the duct hood is fixed to an installation surface on which a large number of ventilation holes are formed, and the installation surface is set on a pier provided on the sea .

  In the pressure control system, the front, upper, and left and right sides of the air inlet of the ventilation duct are covered with the duct hood whose lower part is opened. The wind blown into the air inlet of the air duct from the front, upper, left and right sides of the air duct is blocked by the duct hood. Therefore, since it can suppress that a wind blows into the air inlet of a ventilation duct, the thermal trip phenomenon in a ventilation fan can be suppressed. Thereby, the indoor pressure can be stably maintained.

Moreover, in the said pressure control system, since the duct hood is being fixed to the installation surface, the intensity | strength which can endure a strong wind can be given to the duct hood. Thereby, the intensity | strength as a wind-proof board improves. Moreover, since many ventilation holes are formed in the installation surface, outside air can be sucked from the intake port via the lower opening of the duct hood.

Preferably, prior Symbol pier, LNG receiving operations from LNG tanker to the tank work site and pier monitoring chamber is provided is performed, in a room at the pier monitoring room where the indoor is provided in the vicinity of the working site is there.

  As mentioned above, according to this invention, since it can suppress that a wind blows into the inlet of a duct for ventilation, the thermal trip phenomenon in a ventilation fan can be suppressed. Thereby, the indoor pressure can be stably maintained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

<Configuration>
FIG. 1 shows the overall configuration of the pressure control system. This system controls the indoor pressure in the pier monitoring room of the pier (see FIG. 8) where the LNG receiving work from the LNG ship to the huge tank is performed. Specifically, in this system, a constant amount of outside air is sent from the intake port of the ventilation duct into the pier monitoring room, so that the pressure in the pier monitoring room is always constant (usually atmospheric pressure + 6.5 mmH ₂ O). Hold on. This system includes a ventilation duct 11, a filter unit 12, and a blower fan 13. A duct hood 14 is attached to the air inlet 11 a of the ventilation duct 11. The pier monitoring room 10 is provided with various electric devices for monitoring the LNG receiving work, and is provided in the vicinity of the site where the LNG receiving work is performed.

  The ventilation duct 11 communicates the jetty monitoring room 10 and the external space. The blower fan 13 is provided to send outside air from the air inlet 11 a of the ventilation duct 11 to the pier monitoring room 10. The filter unit 12 is provided to remove foreign matter and moisture contained in the outside air sucked from the air inlet 11a of the ventilation duct 11. The ventilation duct 11 is provided with a backflow prevention damper (BD) and an air volume adjustment damper (VD). The jetty monitoring room 10 has a differential pressure control damper (RD) and an air volume. Adjustment damper (V.D) is installed. By controlling these various dampers, the amount of outside air sucked into the jetty monitoring room 10 through the ventilation duct 11 and the amount of air discharged from the jetty monitoring room 10 can be adjusted.

<Configuration of intake port>
2 and 3 are perspective views of the air inlet portion 11a shown in FIG. The air inlet 11a of the ventilation duct 11 is installed on a scaffold provided on the sea like a pier, for example. The scaffold is provided as an inspection sidewalk such as the air inlet 11a of the ventilation duct 11, and has a large number of ventilation holes (for example, formed by grating). The air inlet portion 11a of the air duct 11 extends substantially horizontally with respect to the installation surface (here, a scaffold), and the air inlet 101 is formed on the tip surface.

  A duct hood 14 is attached to the air inlet 11 a of the ventilation duct 11. The duct hood 14 wraps around the air inlet 101 of the ventilation duct 11 and is opened at the lower side. The opened lower part of the duct hood 14 is fixed to an installation surface (here, a scaffold).

  The duct hood 14 includes a front plate 201 that covers the front of the intake port 101 of the ventilation duct, a rear plate 202 that covers the rear of the intake port 101 of the ventilation duct, and left and right sides of the intake port 101 of the ventilation duct. A pair of side plates 203 to be covered and an upper plate 204 to cover the upper side of the air inlet 101 of the ventilation duct are included.

  The front plate 201 extends obliquely from the installation surface toward the front end surface of the duct in front of the front end surface of the duct (the front end surface where the air inlet 101 is formed). The rear plate 202 faces the front plate 201 behind the front end surface of the duct and extends substantially perpendicularly from the installation surface. The pair of side plates 203 extends substantially perpendicular to the installation surface and connects the left and right ends of the front plate 201 and the left and right ends of the rear plate 202. The top plate 204 connects the upper end of the front plate 201, the upper end of the rear plate 202, and the upper ends of the side plates 203.

  Each of the side plates 203 is narrower toward the top. That is, the linear distance between the front plate 201 and the rear plate 202 becomes shorter as it goes upward. The rear plate 202 is formed with an insertion port 202a into which the intake port 11a of the ventilation duct 11 is inserted.

  As shown in FIG. 3, a connecting member 202b may be provided to reinforce the connection portion (the outer edge portion of the insertion port 202a) between the rear plate 202 and the intake port portion 11a.

  A ventilation port 14 a surrounded by the front plate 201, the rear plate 202, and the side plate 203 is formed below the duct hood 14.

<Action>
FIG. 4 is a side cross-sectional view of the intake port portion 11a. Since the front, upper, left and right sides of the air inlet portion 11a are covered with the duct hood 14, the wind blown substantially horizontally with respect to the installation surface is blocked by the duct hood 14. Therefore, it is possible to suppress the blowing of air into the air inlet 101 of the ventilation duct 11.

  FIG. 5 is a bottom view of the intake port portion 11a. Since the bottom surface of the duct hood 14 is opened to form the ventilation port 14a, the outside air can be sucked from the intake port 101 of the ventilation duct 11 through the ventilation port 14a.

<Effect>
In this way, it is possible to suppress the thermal trip phenomenon in the blower fan, which can suppress the blowing of air into the air inlet of the ventilation duct. Thereby, the pressure inside the jetty monitoring room can be kept constant.

  Moreover, since the open lower part of the duct hood is fixed to the installation surface, the duct hood can be given strength that can withstand strong winds. Thereby, the intensity | strength as a wind-proof board improves.

  In addition, since a large number of ventilation holes are formed in the scaffold, the outside air can be sucked from the intake port of the ventilation duct through the lower opening of the duct hood.

  As shown in FIG. 6 (A), an opening / closing plate 301 may be provided in the air inlet portion 11a of the ventilation duct. In this case, as shown in FIG. 6B, the amount of outside air sucked into the air inlet 101 of the ventilation duct is adjusted by changing the inclination angle of the opening / closing plate 301 with respect to the front end surface where the air inlet is formed. Can do. In this way, by installing an opening / closing plate capable of opening and closing the air inlet 101 of the ventilation duct, the amount of outside air flowing into the ventilation duct 11 can be adjusted.

  Further, the shape of the duct hood may not include the top plate 204 as shown in FIG. 7A, or the front plate 201 may be curved as shown in FIG. 7B. Further, the shape of the duct hood does not have to be such that the front plate 201 is inclined in FIG. That is, the duct hood may have a shape that wraps around the air inlet of the ventilation duct and that is open at the bottom.

  The object to which the pressure control system is applied is not limited to the pier monitoring room. The pressure control system of the present embodiment can be applied to a closed space where the pressure needs to be controlled.

  As described above, the present invention is useful as a pressure control system and the like because it can suppress the thermal trip of the blower fan.

1 is a diagram showing an overall configuration of a pressure control system according to an embodiment of the present invention. It is a front perspective view which shows the external appearance of the inlet port part of the duct shown in FIG. It is a back perspective view which shows the external appearance of the inlet port part of the duct shown in FIG. It is side surface sectional drawing of the inlet port part of the duct shown in FIG. FIG. 2 is a bottom view of an air inlet portion of the duct shown in FIG. 1. (A) It is a perspective view which shows the modification of the inlet port part of a duct. (B) It is side surface sectional drawing which shows the modification of the inlet port part of a duct. (A) It is side surface sectional drawing for demonstrating an example of the shape of the hood for ducts. (B) It is side surface sectional drawing for demonstrating an example of the shape of the hood for ducts. It is the schematic for demonstrating a jetty.

DESCRIPTION OF SYMBOLS 10 Pier monitoring room 11 Ventilation duct 12 Filter unit 13 Blower fan 14 Duct hood 11a Inlet port 101 Inlet port 201 Front plate 202 Rear plate 203 Side plate 204 Top plate 14a Ventilation port 202a Insertion port 202b Connecting member 301 Opening and closing plate

Claims (2)

A system for controlling the indoor pressure to be higher than atmospheric pressure,
A ventilation duct communicating the room and the external space;
A blower fan for sending outside air from the external space into the room through the ventilation duct;
A hollow duct hood that wraps around the air inlet of the air duct and has a lower portion opened by the air vent;
The opening area of the ventilation hood of the duct hood is set larger than the opening area of the intake opening of the ventilation duct,
The passage area of the downstream passage located on the downstream side of the intake port of the ventilation duct is set smaller than the opening area of the intake port of the ventilation duct ,
The vent of the duct hood is fixed to an installation surface on which a large number of ventilation holes are formed,
The pressure control system , wherein the installation surface is set on a pier provided on the sea . In claim 1 ,
The pier is provided with a work site and pier monitoring room where LNG receiving work from the LNG ship to the tank is performed,
The pressure control system characterized in that the room is a room of a pier monitoring room provided in the vicinity of the work site.

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