US20160018120A1

US20160018120A1 - Room pressure controlling system and room pressure controlling method

Info

Publication number: US20160018120A1
Application number: US14/794,117
Authority: US
Inventors: Rintaro OMURA; Yasuhito OMAGARI
Original assignee: Azbil Corp
Current assignee: Azbil Corp
Priority date: 2014-07-15
Filing date: 2015-07-08
Publication date: 2016-01-21
Also published as: KR20160008956A; JP2016020770A; CN105276742A

Abstract

A room pressure controlling system includes: a room pressure correction controlling portion that controls a supply air valve or an exhaust valve, whichever is operated as a room pressure controlling valve, so that a between-room differential pressure between an applicable facility and a reference room that is set to a reference room pressure will match a room pressure set point; an offset flow rate set point switching portion that switches an offset flow rate set point when an instruction has been received from an outside to switch the applicable facility between positive and negative pressure; and a room pressure set point switching portion that switches the room pressure set point in coordination with switching of the offset flow rate set point.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2014-144738, filed on Jul. 15, 2014, the entire content of which being hereby incorporated herein by reference.

FIELD OF TECHNOLOGY

The present disclosure relates to a room pressure controlling system for maintaining a constant room pressure through controlling the supply airflow and exhaust airflow of a room, and in particular to a room pressure controlling system and room pressure controlling method that is compatible with switching between positive and negative pressure of a room.

BACKGROUND

Conventionally, as a technology for switching between a positive pressure operating mode wherein a room that is subject to air exchange is put to a positive pressure, and a negative pressure operating mode, wherein a room that is subject to air exchange is put to a negative pressure, a technology has been proposed for switching the operating mode of an air exchanging device, through a switching operation of a supply/exhaust damper and inverter control of a supply/exhaust fan, where whether the air exchanging device is in the foster pressure operating mode or in the negative pressure operating mode is displayed at the entrance or exit to the room that is subject to air exchange. See, for example, Japanese Unexamined Patent Application Publication No. 2005-114317 (the “JP '317”).
The technology disclosed in the JP '317 makes it possible to achieve switching of the operating mode through operating a positive/negative pressure switching switch that is provided within the room that is subject to air exchange, making it possible to achieve switching of the operating mode in order to prevent, for example, incursion of microbes or dust into the room, or in order to handle an emergency to prevent pathogens from leaking into outside of the room. However, the conventional technology has a problem in that even though a room pressure controlling valve with a small diameter is used when one wishes to control the room pressure strictly, in order for this to handle positive/negative pressure switching, it is necessary to change the flow rates in order to reverse of the differential flow rate between the supply air and the exhaust, and, as a result, it is necessary to increase the diameter of the room pressure controlling valve.
The present invention was created in order to solve the problem set forth above, and an aspect thereof is to provide a room pressure controlling system and room pressure controlling method able to correct the room pressure through a room pressure controlling valve that has a small diameter and wherein the positive/negative pressure of a room can be switched quickly.

SUMMARY

A room pressure controlling system and invention includes: a supply air valve that regulates a flow rate of supply air that is blown out into an applicable facility; an exhaust valve that regulates a flow rate of an exhaust that is drawn in from the applicable facility; a flow rate balance controlling portion that controls the supply air valve or the exhaust air valve, whichever is not used as a room pressure controlling valve, so that the difference between the supply air flow rate, regulated by the supply air valve, and the exhaust flow rate, regulated by the exhaust valve, will match an offset flow rate set point; a room pressure correction controlling portion that controls the supply air valve or the exhaust valve, whichever is operated as the room pressure controlling valve, so that a between-room differential pressure between the applicable facility and a reference room that is set to a reference room pressure will match a room pressure set point; an offset flow rate set point switching portion that switches the offset flow rate set point when an instruction has been received from the outside to switch the applicable facility between positive and negative pressure; and a room pressure set point switching portion that switches the room pressure set point in coordination with switching of the offset flow rate set point.
In one structural example of a room pressure controlling system according to present invention: the offset flow rate set point switching portion, upon reception of an instruction for switching from a positive pressure to a negative pressure, switches the offset flow rate set point from an offset flow rate set point for positive pressure control to an offset flow rate set point for negative pressure control, and, upon reception of an instruction for switching from negative pressure to positive pressure, switches the offset flow rate set point from the offset flow rate set point for the negative pressure control to the offset flow rate set point for the positive pressure control; and the room pressure set point switching portion, upon reception of an instruction for switching from the positive pressure to the negative pressure, switches the room pressure set point from a room pressure set point for positive pressure control to a room pressure set point for negative pressure control, and, upon reception of an instruction for switching from negative pressure to positive pressure, switches the room pressure set point from the room pressure set point for the negative pressure control to the room pressure set point for the positive pressure control.
Moreover, one structural example of a room pressure controlling system according to the present invention includes a room pressure controlling valve that regulates either the supply air flow rate or the exhaust flow rate, instead of operating either the supply air valve for the exhaust valve as the room pressure controlling valve. The flow rate balance controlling portion controls the supply air valve and the exhaust valve so that the difference between the supply air flow rate that is regulated by the supply air valve and the exhaust flow rate that is regulated by the exhaust valve will match an offset flow rate set point.
A pressure controlling method according to present invention includes: a flow rate balance controlling step for controlling, by a flow rate balance controlling portion, a supply air valve or an exhaust air valve, whichever is not used as a room pressure controlling valve, so that the difference between the supply air flow rate, regulated by the supply air valve, and the exhaust flow rate, regulated by the exhaust valve, will match an offset flow rate set point; a room pressure correction controlling step for controlling, by a room pressure correction controlling portion, the supply air valve or the exhaust valve, whichever is operated as the room pressure controlling valve, to cause a between-room differential pressure between an applicable facility and a reference room that is set to a reference room pressure to match a room pressure set point; an offset flow rate set point switching step for switching, by an offset flow rate set point switching portion, the offset flow rate set point when an instruction has been received from the outside to switch the applicable facility between positive and negative pressure; and a room pressure set point switching step for switching, by a room pressure set point switching portion, the room pressure set point in coordination with switching of the offset flow rate set point.
In the present invention, either the supply air valve or the exhaust valve is used as a room pressure controlling valve in order to carry out controlled by switching an offset flow rate set point in coordination with the switching of the room pressure set point when switching the room between positive and negative pressure. In the present invention, the changing of the difference between the supply/exhaust flow rate through positive/negative pressure switching for the room is left up to the supply air valve for the exhaust valve, which ever is not used for the room pressure control valve, and the room pressure control valve is used for only switching the flow rate through switching the room pressure set point and for correcting the room pressure after the switching is completed. The result is that, in the present invention, it is possible to switch the room rapidly between positive and negative pressure and possible to correct the room pressure through the small diameter room pressure controlling valve, thus making it possible to suppress disruption of the room pressure through switching the room between positive and negative pressure. Moreover, the present invention enables the time for switching a room between positive and negative pressure to be shortened through switching the offset flow rate set point in coordination with switching of the room pressure set point.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a diagram illustrating a structure of a room pressure controlling system according to an example according to the present disclosure.

FIG. 2 is a block diagram illustrating an example of a structure for a controller for controlling a supply air valve according to an example according to the present disclosure.

FIG. 3 is a block diagram illustrating an example of a structure for a controller for controlling a room pressure controlling valve according to an example according to the present disclosure.

FIG. 4 is a flowchart for explaining the flow rate balance controlling operation and pressure compensation controlling operation in a room pressure controlling system according to an example according to the present disclosure.

FIG. 5 is a flowchart for explaining the positive/negative pressure switching operation in a room pressure controlling system according to an example according to the present disclosure.

FIG. 6 is a diagram illustrating the state of flow rate switching and room pressure correction control through switching of the offset flow rate set point and the room pressure set point.

DETAILED DESCRIPTION

Forms for carrying out the present disclosure will be explained below in reference to the figures. FIG. 1 is a diagram illustrating a structure of a room pressure controlling system according to an example according to the present disclosure. The room pressure controlling system according to the present example is structured from: a supply air duct 101 for supplying supply air into a room 100; an exhaust duct 102 for exhausting air from the room 100; a supply air valve MAV for regulating the flow rate in the supply air duct 101; an exhaust valve GEX for adjusting the flow rate in the exhaust duct 102; a room pressure controlling valve PCV that is provided in the supply air duct 101; a controller 103 for controlling the supply air valve MAV; a controller 104 for controlling the exhaust valve GEX; a controller 105 for controlling the room pressure controlling valve PCV; a communication line 106 for connecting together the various controllers 103 through 105; a differential pressure sensor 107 for measuring the differential pressure between a prescribed reference room 110 and the room 100; and a positive/negative pressure switching switch 108 that is provided within the room 100.
FIG. 2 is a block diagram illustrating one configuration of a controller 103 according to the present example. The controller 103 is provided with a flow rate balance controlling portion 1 for controlling the supply air valve MAV and the exhaust valve GEX by determining the supply air flow rate for the supply air valve MAV and exhaust flow rate for the exhaust valve GEX so as to cause the difference between the supply air flow rate, which is regulated by the supply air valve MAV, and the exhaust flow rate, which is regulated by the exhaust valve GEX, to match an offset flow rate set point, and an offset flow rate set point switching portion 2 for switching the offset flow rate set point when an instruction for switching the room 100 between positive and negative pressure is received from the outside.
FIG. 3 is a block diagram illustrating one configuration of a controller 105 according to the present example. The controller 105 is provided with: a room pressure correction controlling portion 3 for controlling the room pressure controlling valve PCV to cause the between-room differential pressure between a reference room 110, which is set to a reference room pressure, and the room 100 to match a room pressure set point; and a room pressure set point switching portion 4 for switching the room pressure set point in coordination with switching of the offset flow rate set point.
The airflow rate balance controlling operation and room pressure compensation controlling operation during normal operation of the room pressure controlling system according to the present example will be explained next. FIG. 4 is a flowchart for explaining the flow rate balance controlling operation and room pressure compensation controlling operation. In the present example the explanation will be for a case wherein the room pressure controlling valve PCV is provided in the supply air duct 101. The flow rate of the supply air that is regulated by the supply air valve MAV is defined as Vmav, the flow rate of the supply air that is regulated by the room pressure controlling valve PCV is defined as Vpcv, and the flow rate of the exhaust that is drawn out through the exhaust duct 102 is defined as Vgex.
The flow rate balance controlling portion 1 of the controller 103 determines the supply air flow rate Vmav and the exhaust flow rate Vgex so that the difference between the supply air flow rate Vmav and the exhaust flow rate Vgex will match an offset flow rate set point (Step S1 in FIG. 4).
Vmav=Vgex+α (1)
Note that the flow rate balance controlling portion 1 determines the supply air flow rate Vmav so that at least the lowest flow rate will always blow out so as to satisfy the minimum air exchange flow rate for the subject facilities (the room 100 in FIG. 1).
The flow rate balance controlling portion 1 controls the opening of the supply air valve MAV so that the flow rate of the supply air that is regulated by the supply air valve MAV will go to the flow rate Vmav that was determined in Step S1 (Step S2 in FIG. 4). Moreover, the flow rate balance controlling portion 1 controls the opening of the exhaust valve GEX, through the controller 104, so that the exhaust flow rate that is regulated by the exhaust valve GEX will go to the flow rate Vgex that was determined in Step S1 (Step S3 in FIG. 4).
On the other hand, the differential pressure sensor 107 measures the between-room differential pressure between the room 100 and the reference room 110, which is set to a reference room pressure. The room pressure correction controlling portion 3 of the controller 105 determines a supply air flow rate Vpcv so that the between-room differential pressure, measured by the differential pressure sensor 107, will match the room pressure set point β (Step S4 in FIG. 4). Given this, the room pressure correction controlling portion 3 controls the opening of the room pressure controlling valve PCV so that the flow rate of the supply air that is regulated by the room pressure controlling valve PCV goes to the flow rate Vpcv that was determined in Step S4 (Step S5 in FIG. 4).
The procedures in Step S1 through S5 are repeated at control intervals in this way until the flow rate control is terminated through an instruction from, for example, a user (YES in Step S6 in FIG. 4).
The positive/negative pressure switching operation for carrying out switching of the room 100 between positive and negative pressure will be explained next. Examples of switching the room 100 between positive and negative pressures include, for example, examples where, when carrying out experiments with a biochemical substance in the room 100, for example, the room 100 is normally set to a positive pressure to prevent incursion, into the room 100, of contaminants such as germs, dust, and the like, to cause the room pressure of the room 100 to be higher than the pressure outside, with the differential pressure thereby preventing incursion of the contaminants into the room 100, but when it is necessary to prevent leakage of the biochemical substance to outside of the room 100, the room 100 is put to a negative pressure, so that the room pressure of the room 100 will be less than that which is outside, so that the differential pressure will thereby prevent leakage of the biochemical substance from the room 100. In the present example, the switching of the room 100 between positive and negative pressure can be performed through an individual within the room 100 operating a posture/negative pressure switching switch 108, or a manager of the applicable facility operating a terminal (not shown) in a monitoring center.
FIG. 5 is a flowchart for explaining the positive/negative pressure switching operation. The offset flow rate set point switching portion 2 of the controller 103, upon reception of an instruction to switch between positive and negative pressure, through the positive/negative pressure switching switch 108 or through the operation of the terminal (not shown) (YES in Step S10 in the FIG. 5), switches the offset flow rate set point a (Step S11 in FIG. 5). For the offset flow rate set point a, a positive pressure control offset flow rate set point α1 (for example, α1=+500 m³/h) and a negative pressure control offset flow rate set point α2 (where α2<α1, for example, α2=−300 m³/h) are prepared in advance.
Note that a supply air flow rate Vmav for a time band during the day wherein people are present in the room 100, and a supply air flow rate Vmav for a time band at night wherein people are not present, may be set in advance for both the case of positive pressure control and the case of negative pressure control. Consequently, supply air flow rates Vmav have values that are known, depending on the time band and depending on the positive/negative pressure control, and thus the offset flow rate set point a may be set respectively for the positive pressure control and the negative pressure control in consideration of these known values. At this time, the exhaust airflow rate Vgex is determined so as to satisfy Equation (1), based on the supply air flow Vmav and the offset airflow set point α.
The offset flow rate set point switching portion 2 switches the offset flow rate set point a from the offset flow rate set point al for positive pressure control to the offset flow rate set point α2 for negative pressure control when an instruction has been received for switching from the positive pressure to the negative pressure through the positive/negative pressure switching switch 108 or through the operation of the terminal, and, conversely, switches the offset flow rate set point a from the offset flow rate set point α2 for negative pressure control to the offset flow rate set point al for positive pressure control when an instruction for switching from the negative pressure to the positive pressure has been received.
On the other hand, when an instruction for switching between positive/negative pressure has been received through the positive/negative pressure switching switch 108 or the operation of the terminal, the room pressure set point switching portion 4 of the controller 105 switches the room pressure set point β (Step S12 in FIG. 5). For the room pressure set point β, a room pressure set point β1 (for example, (β1=+20 Pa) for positive pressure control, and a room pressure set point β2 (β2<β1, for example, β2=−20 Pa) for negative pressure control, are prepared in advance.
When an instruction for switching from positive pressure to negative pressure has been received through the positive/negative pressure switching switch 108 or through operation of the terminal, the room pressure set point switching portion 4 switches the room pressure set point β from the room pressure set point β1 for positive pressure control to the room pressure set point β2 for negative control, and, conversely, when an instruction for switching from negative pressure to positive pressure has been received, the room pressure set point β is switched from the room pressure set point β2 for negative pressure control to the room pressure set point β1 for positive pressure control.
The flow rate balance controlling operation and room pressure correcting control operation after the offset flow rate set point α and the room pressure set point β have been switched are as described above.
In order to carry out fine room pressure correction control, the room pressure controlling valve PCV must use a valve with a diameter that is as small as possible. In switching the room 100 between positive and negative pressure, the change in the differential flow rate between the supply air and the exhaust will be large, and thus if the change were controlled by the room pressure controlling valve PCV alone then the diameter of the room pressure controlling valve PCV would be large.
Given this, in the present example two offset flow rate set points a are provided: an offset flow rate set point al for positive pressure control and an offset flow rate set point α2 for negative pressure control, and control is carried out so as to switch the offset flow rate set point α in coordination with switching of the room pressure set point β when switching the room 100 between positive and negative pressure. As a result, the change in the differential flow rates between the supply and exhaust through switching of the room 100 between positive and negative pressure is left up to the supply air valve MAV and the exhaust valve GEX, making it possible for the control of corrections to the room pressure, after the flow rate switching has been completed through switching of the room pressure set point β, to be carried out alone by the room pressure controlling valve PCV. In this way, in the present example it is possible to switch the room 100 between positive and negative pressure quickly and possible to perform room pressure correction control using the small diameter room pressure controlling valve PCV, making it possible to suppress disruption in the room pressure due to the switching of the room 100 between positive and negative pressure. Moreover, the switching of the offset flow rate set point a in coordination with the switching of the room pressure set point β makes it possible to shorten the time for switching the room 100 between positive and negative pressure.
The state of switching the flow rate through the offset flow rate set point α and the room pressure set point β, and switching of the room pressure correction control, is shown in FIG. 6. When setting to a positive pressure, then, as described above, the offset flow rate set point α is set to α1=+500 m³/h, and the room pressure set point β is set to β1=+20 Pa, where, in order to maintain the room pressure centered on the offset flow rate set point, α=α1=+500 m³/h, the flow rate correction control of ±200 m³/h is carried out by the room pressure controlling valve PCV. Similarly, when setting to a negative pressure, then, as described above, the offset flow rate set point a is set to α2=−500 m³/h, and the room pressure set point β is set to β2 =−20 Pa, where, in order to maintain the room pressure centered on the offset flow rate set point, α=α2==500 m³/h, the flow rate correction control of ±200 m³/h is carried out by the room pressure controlling valve PCV.
Note that while the room pressure controlling valve PCV is provided in the supply air duct 101 in the present example, it may be provided in the exhaust duct 102 instead. In this case, Vpcv will be the exhaust flow rate, which is regulated by the room pressure controlling valve PCV.
Moreover, either the supply air valve MAV or the exhaust valve GEX may be used for the room pressure controlling valve PCV. In this case, if the supply air valve MAV is used for the room pressure controlling valve PCV, then the supply air flow rate Vmav is determined as Vpcv by the room pressure correction controlling portion 3, and thus the flow rate balance controlling portion 1 determines the exhaust flow rate Vgex so as to satisfy Equation (1), to control the exhaust valve GEX that is not the one that is used as the room pressure controlling valve PCV. In this case, if the supply air valve MAV is used for the room pressure controlling valve PCV, then the supply air flow rate Vmav is determined as Vpcv by the room pressure correction controlling portion 3, and thus the flow rate balance controlling portion 1 determines the exhaust flow rate Vgex so as to satisfy Equation (1), to control the exhaust valve GEX that is not the one that is used as the room pressure controlling valve PCV.
Each individual controller 103 through 105 explained in the present example can be embodied through a computer that is provided with a CPU (Central Processing Unit), a memory device, and an interface, and a program for controlling these hardware resources. The controllers for each of these CPUs 103 through 105 execute the processes explained the present example through a program that is stored in the memory device.
The present disclosure can be applied to room pressure controlling systems.

Claims

1. A room pressure controlling system comprising:

a supply air valve that regulates a flow rate of supply air that is blown out into an applicable facility;

an exhaust valve that regulates a flow rate of an exhaust that is drawn in from the applicable facility;

a flow rate balance controlling portion that controls the supply air valve or the exhaust air valve, whichever is not used as a room pressure controlling valve, so that the difference between the supply air flow rate, regulated by the supply air valve, and the exhaust flow rate, regulated by the exhaust valve, will match an offset flow rate set point;

a room pressure correction controlling portion that controls the supply air valve or the exhaust valve, whichever is operated as the room pressure controlling valve, so that a between-room differential pressure between the applicable facility and a reference room that is set to a reference room pressure will match a room pressure set point;

an offset flow rate set point switching portion that switches the offset flow rate set point when an instruction has been received from the outside to switch the applicable facility between positive and negative pressure; and

a room pressure set point switching portion that switches the room pressure set point in coordination with switching of the offset flow rate set point.

2. The room pressure controlling system as set forth in claim 1, wherein:

the offset flow rate set point switching portion, upon reception of an instruction for switching from a positive pressure to a negative pressure, switches the offset flow rate set point from an offset flow rate set point for positive pressure control to an offset flow rate set point for negative pressure control, and, upon reception of an instruction for switching from negative pressure to positive pressure, switches the offset flow rate set point from the offset flow rate set point for the negative pressure control to the offset flow rate set point for the positive pressure control; and

the room pressure set point switching portion, upon reception of an instruction for switching from the positive pressure to the negative pressure, switch the room pressure set point from a room pressure set point for positive pressure control to a room pressure set point for negative pressure control, and, upon reception of an instruction for switching from negative pressure to positive pressure, switch the room pressure set point from the room pressure set point for the negative pressure control to the room pressure set point for the positive pressure control.

3. The room pressure controlling system as set forth in claim 1, further comprising:

a room pressure controlling valve that regulates either the supply air flow rate or the exhaust flow rate, instead of operating either the supply air valve for the exhaust valve as the room pressure controlling valve; wherein:

the flow rate balance controlling portion controls the supply air valve and the exhaust valve so that the difference between the supply air flow rate that is regulated by the supply air valve and the exhaust flow rate that is regulated by the exhaust valve will match an offset flow rate set point.

4. A pressure controlling method, comprising:

a flow rate balance controlling step for controlling, by a flow rate balance controlling portion, a supply air valve or an exhaust air valve, whichever is not used as a room pressure controlling valve, so that the difference between the supply air flow rate, regulated by the supply air valve, and the exhaust flow rate, regulated by the exhaust valve, will match an offset flow rate set point;

a room pressure correction controlling step for controlling, by a room pressure correction controlling portion, the supply air valve or the exhaust valve, whichever is operated as the room pressure controlling valve, to cause a between-room differential pressure between an applicable facility and a reference room that is set to a reference room pressure to match a room pressure set point;

an offset flow rate set point switching step for switching, by an offset flow rate set point switching portion, the offset flow rate set point when an instruction has been received from the outside to switch the applicable facility between positive and negative pressure; and

a room pressure set point switching step for switching, by a room pressure set point switching portion, the room pressure set point in coordination with switching of the offset flow rate set point.

5. The room pressure controlling method as set forth in claim 4, wherein:

in the offset flow rate set point switching step, upon reception of an instruction for switching from a positive pressure to a negative pressure, the offset flow rate set point switching portion switches the offset flow rate set point from an offset flow rate set point for positive pressure control to an offset flow rate set point for negative pressure control, and, upon reception of an instruction for switching from negative pressure to positive pressure, switches the offset flow rate set point from the offset flow rate set point for the negative pressure control to the offset flow rate set point for the positive pressure control; and,

in the room pressure set point switching step, upon reception of an instruction for switching from the positive pressure to the negative pressure, the room pressure set point switching portion switches the room pressure set point from a room pressure set point for positive pressure control to a room pressure set point for negative pressure control, and, upon reception of an instruction for switching from negative pressure to positive pressure, switches the room pressure set point from the room pressure set point for the negative pressure control to the room pressure set point for the positive pressure control.

6. The room pressure controlling method as set forth in claim 4, comprising:

a room pressure controlling valve for regulating either the supply air flow rate or the exhaust flow rate, instead of operating either the supply air valve for the exhaust valve as the room pressure controlling valve; wherein:

in the flow rate balance controlling step, the flow rate balance controlling portion controls the supply air valve and the exhaust valve so that the difference between the supply air flow rate that is regulated by the supply air valve and the exhaust flow rate that is regulated by the exhaust valve will match an offset flow rate set point.