JPH038454B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to ducts.

For example, in a known four-section electrostatic precipitator, four sections DS1, DS2, DS3,
DS4 are built in parallel in the common duct D, and the inlet and outlet of the duct D are provided with an inlet damper DI and an outlet damper DE, respectively.

In such an electrostatic precipitator, when dust is to fall from the element, one section out of the four sections is shielded and the third section is operated at its normal rating. Since they are aligned perpendicular to the gas flow, stagnation upstream causes drift in the section. In addition, if there is a bend or pocket downstream, as shown in Figure 4A and Figure 4B, respectively,
The secondary flow influences the formation of the flow, and the flow,
increases or decreases its area, causing vibration and noise in the duct.

Conventionally, when damper valves are installed in large-diameter ducts, the shape and arrangement of the valves are simple because the purpose is to shield them, but the disturbance of the streamlines due to secondary flow and separation and the flow rate adjustment function are In the case of the electrostatic precipitator mentioned above, the perforated plate PP is connected to the inlet damper D1 and sections S1 to
Although it is inserted between S4 and S4, such a means is disadvantageous because it involves an increase in pressure loss.

The present invention has been proposed in view of the above circumstances, and is designed to adjust the flow rate of the main flow of the duct, prevent uneven flow to the built-in devices, and reduce pressure loss in the duct in a duct that incorporates multiple devices such as heat exchangers. The purpose of the present invention is to provide a duct that reduces frequency noise and vibration.

To this end, the present invention provides a plurality of parallel dampers on the inlet and outlet sides of a duct that incorporates a plurality of devices arranged in parallel in a common main flow, and partially opens and closes both dampers, thereby controlling the plurality of devices. In the duct, a plurality of inlet dampers are provided on the inlet side of the duct and arranged to expand in a V-shape toward the upstream, and an outlet of the duct. It is characterized by comprising a plurality of outlet dampers arranged on the side so as to expand in a V-shape toward the downstream side.

An embodiment of the present invention will be explained with reference to the drawings.
5A and 5B are longitudinal sectional views showing the first embodiment, in which FIG. 5A shows the case when both sides are operated, and FIG. 5B shows the case when one side is operated. FIGS. 6A and 6B are longitudinal sectional views showing the second embodiment, in which FIG. 6A shows the case when both sides are operated, and FIG. 6B shows the case when one side is operated. 7A, B, C, and D are partially enlarged views showing the dampers of FIGS. 5 and 6, respectively, with A showing the inlet damper and B, C, and D showing the outlet damper, respectively. FIG. 8 is a partially enlarged view showing the flow near the exit damper in FIG. 5A.

In the above diagram, 1 and 1' are the duct and 2, respectively.
-1 and 2-2 are a pair of heat exchangers built in the ducts 1 and 1' in parallel with each other, and 3 is a plurality of inlet dampers arranged so as to expand in a V-shape toward the upstream. ing. Reference numeral 4 denotes a plurality of outlet dampers, which are arranged so as to expand in a V-shape toward the downstream. A partition plate 5 is provided on the center line of the ducts 1, 1' and partitions the heat exchangers 2-1, 2-2.

In such a duct, the duct 1 has a uniform cross section and the duct 1' has a varying cross section.

First, when operating both heat exchangers 2-1 and 2-2, the inlet damper 3 must introduce the fluid without causing uneven flow. In FIG. 4A, each is fixed at an inclination angle of S2.

At this time, the outlet damper 4 adjusts the throttle amount to flow a required flow rate of fluid to each heat exchanger 2-1, 2-2, but adjacent dampers rotate symmetrically with respect to each other.

Then, as shown in Fig. 8, the nozzle jets flowing between adjacent dampers become counterflows and mix, so they become a uniform flow with small turbulence and the secondary flow disappears. Even if there are vents or pockets downstream, it will be difficult for secondary flow to take hold, so noise and vibration will be greatly reduced.

Next, when only one heat exchanger, for example 2-2, is operated, the inlet damper 3 and outlet damper 4 on the heat exchanger 2-1 side are closed, and in the case of FIG. 3B, Inlet/outlet damper 3 at inclination angle S1
In the case of FIG. 4B, the inclination angle S3 is fixed, and the inclination angles S1 and S3 are set so that the total flow rate is
When flowing to 2, set the angle so that the streamlines are aligned.

Then, the damper 3 on the heat exchanger 2-1 side,
4 are each closed and form an inclined surface as a whole, so the duct has a continuous cross-sectional change and the streamlines are uniformly rectified.

In each of the above embodiments, as for the shape of the damper, the inlet damper 3 has a conventional cross-sectional shape as shown in FIG. Since separation vortices are generated on the sides, which is a problem, an elliptical cross section, an airfoil cross section, etc. are used to prevent flow separation, as shown in Figures B, C, and D, respectively.

In short, according to the present invention, a plurality of parallel dampers are provided respectively on the inlet side and the outlet side of a duct containing a plurality of devices arranged in parallel in a common main flow, and by partially opening and closing both dampers, the plurality of devices are A duct in which a part of the duct can be selectively shut off from the rest of the duct includes a plurality of inlet dampers provided on the inlet side of the duct and arranged to expand in a V-shape toward the upstream side; The present invention is industrially extremely useful because a quiet and high-performance duct is obtained by including a plurality of exit dampers arranged on the exit side and expanding in a V-shape toward the downstream. It is something.

[Brief explanation of the drawing]

1 and 2 are a side view and a plan view, respectively, showing a known four-section split electrostatic precipitator, FIG. 3 is a partially enlarged view showing the downstream flow of the damper in FIG. 1, and FIG. 5A and 5B are longitudinal sectional views showing the first embodiment of the present invention, respectively. FIGS. 6A and 6B are vertical cross-sectional views showing the second embodiment, respectively. FIG. 6A shows the operation on both sides, and FIG. 6B shows the operation on one side. 7th
Figures A, B, C, and D are partially enlarged views showing the dampers of Figures 5 and 6, respectively, with Figure A showing the inlet damper, and Figures B, C, and D showing the outlet dampers, respectively. FIG. 8 is a partially enlarged view showing the flow downstream of the outlet damper in FIG. 5. 1, 1'... Duct, 2-1, 2-2... Heat exchanger, 3... Inlet damper, 4... Outlet damper, 5... Partition plate.

Claims (1)

[Claims] 1. A plurality of parallel dampers are provided on the inlet and outlet sides of the ducts containing multiple devices installed in parallel in a common mainstream, and some of the above-mentioned devices are selected by partially opening and closing both dampers. A duct that can be shut off from the rest of the duct, including a plurality of inlet dampers provided on the inlet side of the duct and arranged so as to expand in a V-shape toward the upstream side, and a plurality of inlet dampers provided on the outlet side of the duct. A duct comprising a plurality of outlet dampers arranged to expand in a V-shape toward the downstream side.