JPS6144219B2 - - Google Patents

Description

[Detailed description of the invention] This invention requires differential pressure control to maintain the pressure inside the building at a negative pressure value within a certain range with respect to the outside of the building, such as in a ventilation air conditioning system in a nuclear power plant. A building differential pressure control device that constantly controls the pressure inside the building to maintain a negative pressure value within a certain range in a certain ventilation air conditioning system, and at the same time reliably controls the air volume at a constant level in order to maintain the ventilation frequency and remove heat. It is related to.

The conventional method for controlling negative pressure inside a building is to detect the air volume on the downstream side of the supply air blower, and use the output signal of a controller that receives the signal from the detector to control the damper on the upstream side of the supply air blower. It controlled the opening.
However, with this method, if the exhaust air filter becomes clogged, the negative pressure value inside the building tends to decrease, and if it becomes extremely clogged, there is a risk that the negative pressure cannot be maintained. In addition, dampers have poorer controllability than suction vanes, and this tendency is particularly pronounced when static pressure is large.

The present invention has been made in view of the above circumstances, and its purpose is to provide a setting means for setting a pressure difference between an air supply line and an exhaust line when a suction vane is initially set; A building differential pressure control device for a ventilation air conditioning system that can always obtain a negative pressure within a constant width and also secure a constant air volume by comprising means for controlling the suction vane so that the difference becomes a set value. Our goal is to provide the following.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Figure 1 shows the ventilation air conditioning system that controls the building differential pressure. This ventilation air conditioning system takes in outside air from a louver 11, removes dust with a supply air filter 12, and then supplies the air into a building 15 via a supply air heater 13 and the like with a supply air blower 14. be. Next, the air supplied into the building 15 is collected by the exhaust duct 16 and passed through the exhaust air filter 1.
After being subjected to dust removal processing by the exhaust blower 18, it is discharged from the exhaust pipe 20 to the outside of the building.
A suction vane 19 is attached to the exhaust blower 18 so that the air volume can be adjusted. The detection points are provided on the output side of the supply air blower 14 of the supply air line and on the input side of the exhaust air filter 17 of the exhaust line,
When the suction vane 19 is initially set, the pressure difference on both sides is detected and this output signal 2 is generated.
It is equipped with a differential pressure detector 21 that outputs 1A. The output signal of the differential pressure detector 21 (the output signal 21A of the differential pressure detector 21 when the suction vane 19 is initialized) is inputted and set as a set value. Means 22 is provided for outputting an output signal 22A for controlling the suction vane 19 so that the set value of the setting means and the output of the differential pressure detector match.

In the ventilation air conditioning system having such a configuration, assuming that there is no significant leakage of air between the louver 11 and the exhaust stack 20, one duct system is formed between the louver 11 and the exhaust stack 20. FIG. 2 shows a conceptual diagram of the pressure distribution in each part of this system. In FIG. 2, the upper side of the atmospheric pressure line shows positive pressure, and the lower side shows negative pressure. When the air filters 12 and 17 of the supply and exhaust systems are clean at the beginning of system operation, the pressure distribution is stable as shown by the solid line 30A in FIG. As the system operation continues and the supply air filter 12 becomes clogged, the pressure distribution becomes as shown by the broken line 30B, and the negative pressure in the building 15 increases by the amount of pressure loss increase due to the supply air filter 12 being clogged. Next, when the exhaust air filter 17 is also clogged, the pressure distribution becomes as shown by the dashed line 30C. In this way, the internal pressure between the outside air intake louver 11 and the exhaust stack 20 of the ventilation air conditioning system shown in FIG. 1 changes by the amount of change in device resistance due to clogging of the air filter.

Figure 3 shows a typical blower characteristic curve, where the horizontal axis shows air volume and the vertical axis shows static pressure.The device resistance curve is 42A, and the blower characteristic curve is 41A.
Then, the static pressure loss when the air volume Q1 flows is P1
(point of action X). If the air filter becomes clogged and the device resistance curve reaches 42B, Q1 continues.
In order to flow an air volume of , a static pressure of P3 is required (point of action Z). However, when the characteristic curve of the blower does not change, the point of action becomes Y, the air volume decreases to Q2, and the static pressure loss increases to P2 and becomes stable. Therefore, when determining the capacity of the blower with suction vane 19, it should be selected in advance so that it has enough capacity to cover the increase in device resistance due to filter clogging, and at the beginning of system operation, Suction vane 19 as much as possible
The filters 12 and 17 are operated by changing the inflow angle of the filters 12 and 17.
The suction vane 19 is controlled to change the characteristic curve of the blower 18 from 41A to 41B.
If the static pressure is increased to maintain the air volume Q1 (point of action Z), the air volume can be kept constant even when the device resistance changes. That is, to explain this with reference to FIG. 2, the exhaust blower 18
The capacity (static pressure) of the exhaust fan 18 is selected in advance as A-D, and at the beginning of operation, by changing the inflow angle of the suction vane 19, the air blowing capacity of the exhaust blower 18 is used as A-B. By controlling the suction vane 19 according to the clogging and changing the capacity of the exhaust blower 18 from AC to AD, the air volume is always constant and the inside of the building is kept within a certain width (32cm in Fig. 2). This means that it is possible to maintain the negative pressure within the negative pressure value (shown as ).

Next, the operation of the means 22 for controlling the suction vane 19 in this manner will be explained. In FIG. 1, the means 22 receives an output signal 21 from a differential pressure detector 21 that detects the differential pressure in the supply and exhaust lines.
A causes an output signal 22 to be sent to the suction vane 19.
This relationship will be explained based on FIG. 2. The pressure value at the supply side detection position of the differential pressure detector 21 is the value 34 in the pressure distribution diagram, and the pressure value at the exhaust side detection position is the value 35. That is, the sum 36 of the absolute values of the pressure value 34 on the supply side and the pressure value 35 on the exhaust side becomes the initial pressure loss at the location detected by the differential pressure detector 21 in this system.

Therefore, at the beginning of system operation, the pressure difference 36 between the supply line and the exhaust line when the negative pressure value in the building 15 falls within the specified width 32 is measured, and this pressure difference 36 causes the suction vane 19 to By initially setting the inflow angle, the supply air filter 1
Even when the pressure distribution becomes as shown by the broken line 30B in FIG. 2 due to the clogging of the exhaust air filter 17,
Even when the pressure distribution becomes as shown by the dashed line 30C due to clogging, the suction vane 19 is controlled so as to always maintain the initially set pressure difference 36, and this causes the exhaust blower 18 to switch between A-C or A-D. This means that control is performed to always obtain a negative pressure value within a certain range and a constant air volume.

In this way, the indoor negative pressure control device for ventilation and air conditioning systems of the present invention can be used in an extremely short period of time and with good stability even if the conditions of the process system change during continued operation.
It is possible to control the pressure inside the building to always maintain it within a certain negative pressure range relative to the outside of the building, and at the same time to control the amount of air flow to be constant.In addition, the device of this invention prevents the increase in device resistance due to clogging of the air filter. In contrast, the negative pressure inside the building will increase, making it safer than the conventional system.

[Brief explanation of the drawing]

Figure 1 is a general ventilation air conditioning system diagram used in nuclear power plants to which this invention is applied, Figure 2 is a conceptual diagram of pressure distribution in the system diagram of Figure 1, and Figure 3 is a general diagram. FIG. 3 is a diagram showing a typical blower characteristic curve. 11...louver, 12...supply air filter, 13
... Supply air heater, 14... Supply air blower, 15... Building,
16...Exhaust duct, 17...Exhaust air filter, 1
8...Exhaust blower, 19...Suction vane, 20
...Exhaust pipe, 21...Differential pressure detector, 22...Means for controlling suction vane 19.

Claims (1)

[Claims] 1 It has a line that supplies outside air into the building through a supply air filter and a supply air blower, and a line that exhausts the air supplied into the building to the outside of the building through an exhaust air filter and suction vane with an exhaust blower. , in a ventilation air conditioning system in which the pressure inside the building needs to be maintained at a predetermined value negative pressure than the pressure outside the building, the air supply blower when the suction vane is initially set so that the negative pressure becomes the predetermined value. A differential pressure detector detects the difference between the pressure on the output side of the exhaust air filter and the pressure on the input side of the exhaust air filter, and the output of the differential pressure detector when the suction vane is initialized is input and this is set as the set value. What is claimed is: 1. A building differential pressure control device for a ventilation air conditioning system, comprising: a setting means for setting the pressure difference; and a means for controlling the suction vane so that the output of the differential pressure detector becomes a set value of the setting means.