JPH0336844Y2 - - Google Patents

Description

[Detailed description of the invention] When air-conditioning each room in a building, the ducts are branched to supply conditioned air to each room, thereby air-conditioning the indoor air. For example, when controlling the indoor temperature, if the amount of air supplied into the room is a constant air volume, the air supply temperature can be easily determined, so the indoor air conditioning can be controlled. can be performed with high precision.

Conventionally, the amount of air supplied to each room has been controlled by adjusting the size of the duct in the duct system and the opening of the blades of the air volume adjustment damper.

However, if pressure fluctuations occur within the duct due to various circumstances, the pressure of the air supplied to each room, and therefore the air volume, will fluctuate.

However, conventional air volume adjustment dampers have a structure in which the blade opening degree is adjusted manually or driven by a motor, and the air volume is thereby adjusted. Therefore, it is impossible to adjust the air volume unless the blade opening is adjusted manually or by driving a motor, and it is also impossible to constantly adjust the air volume.

Therefore, as a constant air volume device that eliminates this inconvenience and drawback, a constant air volume maintenance device as disclosed in Japanese Utility Model Publication No. 52-89851, for example, has been proposed.

This is done by installing a thin conical coil-shaped spring plate with its top side directly facing the direction of air blowing, and allowing air to flow through gaps between the coiled spring plates. The coiled spring plate expands and contracts in response to changes in wind pressure on the primary side of the ventilation duct, and its ventilation gap area is automatically changed, so that even if the wind pressure on the primary side fluctuates, the ventilation gap of the coiled spring plate does not change. It has a structure that maintains a constant amount of air flowing through it.

According to this, the conical coil spring plate expands and contracts in response to changes in wind pressure on the primary side, and the ventilation gap area automatically changes, so a constant air volume is maintained without the need for manual or motor drive operations. becomes possible.

However, since the conventional structure described above is a one-piece structure, it is necessary to adjust the relationship between the displacement of the conical coil-shaped thin spring plate in response to wind pressure fluctuations, the ventilation gap area, the resistance coefficient at each opening degree, and therefore the pressure loss. It was not easy to manufacture the shape.

Further, it was difficult to adjust the air flow rate to maintain a constant air volume in response to actual pressure fluctuations.

In other words, the complex and delicate behavior of fluid cannot be solved by qualitative structure alone, but cannot be solved unless it is dealt with quantitatively. However, since the above constant air volume maintenance device has an integral structure, this quantitative solution cannot be solved. was difficult.

This invention was devised to eliminate the above-mentioned drawbacks, and its purpose is to easily and accurately maintain a constant airflow rate over a wide range of pressure fluctuations, even in response to complex and subtle pressure fluctuations within the duct. An object of the present invention is to provide a constant air volume device that can be adjusted and maintained.

In order to achieve the above object, the constant air volume device according to the present invention includes: an annular stopper provided in the middle of a duct; an annular body having an opening provided in contact with the upstream side of the annular stopper; A plurality of rods fixed to the body, a bearing support plate removably provided at both ends of the rod, bearings provided on each of the bearing support plates, and a reciprocating rod slidably inserted through both the bearings. and an air volume adjusting valve plate fixedly installed perpendicularly to the retractable rod between the annular body and the bearing support plate, and fixed at an arbitrary position on the retractable rod between the bearing and the annular body. A compression coil spring seat is provided, and a plurality of compression coil springs having different lengths and spring diameters are detachably fitted to the reciprocating rod and are loosely fitted between the compression coil spring seat and the bearing. It is characterized by

〔Example〕

Hereinafter, the features of the present invention will be specifically explained with reference to the drawings.

FIG. 1 shows a side cross section of the constant air volume device in this embodiment.

In the figure, an annular stopper 6 is molded to bulge inward at the middle part of a cylindrical duct 1. Therefore, a constricted portion 2 is formed in the flow path A of the duct 1 by the annular stopper 6. And the annular stopper 6
An annular body 7 having a large opening 3 in the center is attached to the upstream side of the annular body 7, and a gasket 14 is adhesively solidified in order to make the contact area between the annular body 7 and the annular stopper 6 airtight. Reference numeral 15 designates leaf springs for press-fitting and fixing the annular body 7 to the inner wall of the duct 1, which are provided at appropriate locations on the inner wall of the duct 1, as shown in FIG.

An opening is provided in the annular body 7, and two rods 8,
8' is provided parallel to the flow path A. This rod 8,
8' has a required length, and engages with the annular body 7 by passing through the engaging members 16, 16'.

At both ends of the rods 8, 8' there are threaded parts 8a, 8.
a' are provided, and bearing support plates 9, 9' are detachably suspended from these threaded portions 8a, 8a'.
The shape of the bearing support plates 9, 9' is, for example, rectangular in order to reduce flow path resistance.
There are openings in the portions corresponding to a and 8a', and the rods 8 and 8' can be freely attached and detached by nuts.

Bearings 11, 1 are located in the center of the bearing support plates 9, 9'.
1' are opposed to each other and are detachably attached using screws. The retractable rod 10 is slidably inserted into the bearings 11, 11'. Advance/retreat rod 10
is designed to be able to slide by a required length, that is, by a length necessary for adjusting the air volume while being inserted into the bearings 11, 11'.

An air volume adjusting valve plate 4 is fixed to the reciprocating rod 10 between the annular body 7 and the bearing support plate 9'. The air volume adjusting valve plate 4 has a diameter d smaller than the diameter of the duct 1 so that gaps B and B' are formed between the valve plate 4 and the duct 1 to allow a required amount of air to pass through. Moreover, the diameter d is made slightly smaller than the diameter of the opening 3, as shown in FIG. 2, to reduce the flow path resistance, and the opening 3 is kept in a fully closed state by the air volume adjustment valve plate 4. It is configured so that it does not occur.

On the other hand, a compression coil spring seat 12 is fixed at an arbitrary position on the reciprocating rod 10 between the annular body 7 and the bearing support plate 9 by a compression coil spring seat set screw 13. As shown in FIG. 3, three compression coil springs 5, 5', and 5'' having different lengths and spring diameters are loosely inserted between the compression coil spring seat 12 and the bearing 11. Here, various compression coil springs 5, 5', 5'' having different spring constants, lengths, and spring diameters are attached.

When wind pressure is applied in the A direction to the device configured as described above, pressure is applied to the air volume adjusting valve plate 4, and the advancing/retracting rod 10 slides in the A direction.

When the advancing/retracting rod 10 moves, the compression coil spring seat 12 moves and compresses the compression coil spring 5 between it and the bearing 11. Then, the air volume adjusting valve plate 4 stops at a position where the load applied to the air volume adjusting valve plate 4 and the spring force of the compression coil spring 5 are balanced. At this time, the outer wall surface s of the truncated cone formed by the outer edge of the air volume adjusting valve plate 4 and the outer edge of the opening 3 serves as an opening area for ventilation, and a constant amount of air is passed through. As the wind pressure in the A direction increases, the compression coil spring 5 is further compressed, and then the compression coil spring 5' is compressed. and,
The air volume adjusting valve plate 4 stops at a position where the load applied to the air volume adjusting valve plate 4 and the spring force of the compression coil springs 5, 5' are balanced, and a constant amount of air is allowed to flow.

When the wind pressure increases further, the compression coil spring 5,
5' are both compressed, and the compression coil spring 5'' is further compressed, and the air volume adjustment valve is closed at a position where the load applied to the air volume adjustment valve plate 4 and the spring force of the compression coil springs 5, 5', and 5'' are balanced. The plate 4 is stopped and allows a constant amount of air to pass through.

Here, in advance, various pressure states are created in the duct 1 of the constant air volume device according to the present invention from which the compression coil springs 5, 5', and 5'' are removed, and air volume adjustment is performed so that the air flow rate becomes constant. The valve plate 4 is manually moved to confirm the position where a constant air volume is obtained, and the aerodynamic force (load) acting on the air volume adjustment valve plate 4 at that position is first measured.An example of the load curve is shown in Figure 4. The horizontal axis represents the position (displacement amount) of the air volume adjusting valve plate 4, and the vertical axis represents the aerodynamic force (load) acting on the air volume adjusting valve plate 4 in g.

At this time, the relationship between the position of the air volume adjusting valve plate 4 and the amount of air (load) acting on the air volume adjusting valve plate 4 becomes a quadratic curve, which is non-linear. Therefore,
Since the spring force is proportional to the amount of displacement, that is, it has a linear characteristic, a plurality of compression coil springs 5 with different lengths and spring diameters are used to generate a spring force urging in the windward direction that is equal to the aerodynamic force (load). Adjust by combining 5' and 5''.

In the illustrated embodiment, three large, medium and small compression coil springs 5, 5', 5'' are connected to a compression coil spring seat 12,
It is attached between the bearings 11.

As shown in FIG. 4, under a constant air volume, the amount of displacement of the air volume adjustment valve plate 4 and the aerodynamic force (load) acting on the air volume adjustment valve plate 4 form a quadratic function curve as follows. Due to the following reasons. In other words, pressure is proportional to the square of wind speed and proportional to the square of flow rate.

ΔP∝ν ² ∝Q ^2On the other hand, the displacement of the spring is proportional to the spring force.

α∝F Therefore, by making the spring force F, (pressure Δp) proportional to the square of the flow rate, the constant air flow characteristic curve shown in FIG. 4 can be approximated. That is, as shown in FIG. 6, a spring force curve (more precisely, a polygonal line) that approximates the load curve shown in FIG. 4 can be obtained. In this way, one set of compression coil springs 5,
The biasing force of 5', 5'' can be adjusted before mounting on the actual duct 1. A pair of compression coil springs 5, 5', 5'' mounted on the duct 1 are adjusted in advance so that the air volume is constant. Because it is regulated, the amount of ventilation remains constant regardless of fluctuations in duct pressure. The fifth example of the experiment is
As shown in the figure. As you can see, we were able to maintain an accuracy of about ±5% over a wide range of duct pressure fluctuations from 10 to 36 mmAp, and maintain a constant air volume up to a high duct pressure of 36 mmAp.

Here, the characteristics of this example are as follows:
If the air flow deviates from the constant air flow due to the change in duct pressure shown in Fig. 5, it can be corrected by immediately replacing the compression coil springs 5, 5', 5'' with other suitable ones based on the characteristic curve. This means that it can be done extremely easily and accurately.Compression coil springs 5, 5',
5'' can be replaced by simply removing the bearing support plate 9 and the nuts.

The second characteristic feature of this embodiment is that the opening area s can be adjusted by moving and fixing the engaging members 16, 16' to any position on the rods 8, 8', and the constant air volume can be adjusted. It is possible to adjust the set air volume.

A further characteristic feature of this embodiment is that even if the wind pressure in the a direction increases significantly for some reason, the opening is not completely closed by the air volume adjustment valve plate 4, resulting in a sudden pressure increase. Avoid damaging parts etc.

As explained above, according to the constant air volume device according to the present invention, a plurality of compression coil springs having different lengths and spring diameters are provided between the compression coil spring seat and the bearing, so that the spring force curve can be doubled. The following curve can be approximated, and the quantitative performance curve can be approximated in a wide wind pressure range to realize a constant air volume.

Furthermore, since the bearing support plate is removably mounted on the rod, it is possible to easily obtain a constant air volume with high precision by replacing the compression coil spring with another suitable one.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the constant air volume device according to the present invention, Fig. 2 is a sectional view taken along the line shown in Fig. 1, and Fig. 3 is an installation of the compression coil spring of the same embodiment. Figure 4 is an explanatory diagram showing the state, and Figure 5 is a load curve diagram showing the relationship between the constant air volume position (displacement) of the air volume adjustment valve plate and the aerodynamic force (load) acting on the air volume adjustment valve plate. 6 is a quantitative performance curve diagram showing the relationship between duct pressure and air volume of the same embodiment, and FIG. 6 is a spring force curve (broken line) diagram of the compression coil spring of the same embodiment. 1... Duct, 3... Opening, 4... Air volume adjustment valve plate, 5, 5', 5''... Compression coil spring, 8,
8'...rod, 9,9'...bearing support plate, 10...
...Advancing/retracting rod, 11, 11'... Bearing, 12... Compression coil spring seat, 16, 16'... Engaging member.

Claims (1)

[Scope of utility model registration request] An annular stopper provided in the middle of the duct, an annular body having an opening provided in contact with the upstream side of the annular stopper, a plurality of rods fixed to the annular body, and a rod that can be attached and detached from both ends of the rod. a bearing support plate provided so as to be movable; a bearing provided on each of the bearing support plates; and a reciprocating rod slidably inserted through both the bearings;
An air volume adjusting valve plate is fixedly installed perpendicularly to the retractable rod between the annular body and the bearing support plate, and can be fixed at any position on the retractable rod between the bearing and the annular body. A compression coil spring seat is provided, and a plurality of compression coil springs having different lengths and spring diameters are removably fitted loosely to the retractable rod between the compression coil spring seat and the bearing. Characteristic constant air volume device.