JPS6214400Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air volume control device for controlling the air volume of an air blower by changing the angle of a plurality of vanes provided at the suction port of the air blower.

In general, an air volume control device (referred to as radial vane control) in which multiple movable blades or vanes are installed outside the suction port and the vane axis is approximately parallel to the main axis of the blower is shown in Figures 1 and 2. A plurality of vanes 5 are rotatably installed in a suction sleeve 4 having a suction port 2 connected to an impeller 1 in a casing 3 to form a vane control device, and the vanes 5 are interlocked by a connecting ring outside the suction sleeve 4. This is an attempt to efficiently control the operating air volume by changing the vane angle from the fully open position to give the gas a whirl in the impeller rotation direction, but compared to normal vane control, the link The mechanism can be taken out of the suction sleeve, and by making the vane shaft cantilevered, the bearing can also be taken out of the suction sleeve, so it is often used in blowers that handle high-temperature gas. However, the conventional method had the disadvantage that as the vane was closed, low-frequency pulsations were generated and vibration noise was generated. For example, when the vane opening is narrowed down to about 15° to 45°, the swirling becomes too strong and a vortex is created, which swirls continuously inside the vane and generates vibration noise, which is a problem in terms of pollution prevention. .

The present invention aims to provide a vane control device that accurately eliminates these conventional drawbacks.

In the present invention, the operation of the vane in the closing direction,
Especially when the vane opening angle is 15° to 45°, low frequency (30Hz to
100Hz) pulsations occur, and the vibrations and noise become intense, but it has become clear that the cause of this is that the vortex generated inside the vane is spinning around, in other words, a turning velocity phenomenon is occurring. So,
The present invention is characterized in that a partition plate for preventing this turning is disposed in a radial direction on the inner peripheral side of the movable blade, at a position upstream from the suction port and downstream from the movable blade.

In Figures 3 and 4, 1 is an impeller, 2 is a suction port, 3 is a casing, 4 is a suction sleeve, and 5 is a vane that becomes a movable blade of a vane control device, which is formed from a metal plate into an airfoil shape. A plurality of vanes are installed outside the suction port 2, and the shaft 6 of the vane 5 is arranged parallel to the main shaft 10 of the blower to provide radial vane control. A partition plate 7 is installed to block and destroy the swirling vortex inside the vane to prevent a swirling velocity from occurring, thereby preventing vibration and noise due to low frequency pulsation.

The partition plate 7 may be installed at any position on the inner circumferential side of the vane 5 as a rotation prevention plate, and the number of partition plates 7 may be 1.
It may be provided with one sheet or multiple sheets, and can be selected and provided. Further, the effect of noise prevention is higher when the partition plate 7 is installed as close to the vane 5 as possible and when the size thereof is large. Furthermore, if the partition plate 7 for preventing rotation is too large, the shaft power when the vane 5 is squeezed increases and the energy saving effect decreases, so it is only necessary to determine the optimum shape. On the other hand, since the vane 5 can only move by 90 degrees, it is convenient to install it in the position shown in the figure because it can be installed close to the vane 5 without interfering with the vane 5.

In addition, as shown in FIG. 3, if an inner cone-shaped guide 8 is provided from the inside of the suction sleeve 4 toward the impeller 1 side, if the guide 8 is installed, the flow will be directed toward the impeller 1. This is preferable because it can be smoothly guided toward the entrance and at the same time, the partition plate 7 can be more firmly fixed on two sides. If the cone-shaped guide 8 is not provided, one or more partition plates 7 may be provided on the inner surface of the side wall of the casing 3 so as to protrude inward, as shown in FIG. Moreover, the blower can be applied to either a double-end suction type or a single-side suction type.

In the figure, 9 is a lever, 11 is a link mechanism, 12 is a bearing, and 13 is a base.

It should be noted that the low-frequency noise difference between conventional examples b ₁ , b ₂ , b ₃ in which the partition plate 7 as a rotation prevention plate is not provided and embodiments a ₁ , a ₂ , a ₃ of the present invention in which the partition plate 7 is provided. When the levels were compared, the results shown in Figure 6 were obtained. In the diagram
a ₁ and b ₁ have a vane opening of 15°, a ₂ and b ₂ have a vane opening of 30
゜, a ₃ , b ₃ indicate the noise level when the vane opening is 45 degrees.

A large-scale actual machine with an impeller outer diameter of 3140 mm and a rotation speed of 580 rpm was manufactured, and noise measurements were conducted during factory performance tests.

In order to compare with a model machine without countermeasures, the comparative noise dB _s of low frequency noise is calculated as follows: dB _s = dBL−10Kg (Q×P ² _T ÷ 60) [where dBL: low frequency noise level, Q: air volume (m ^{3 )} /m), P _T :Total pressure (mmAq)], the model machine without countermeasures has dB _s ≒
52dB, dB _s of the actual machine was ≒34dB, and low frequency noise was significantly reduced, confirming the effect of the partition plate even in the actual machine.

The present invention makes it possible to prevent low-frequency noise, that is, vibration and noise caused by low-frequency pulsation, which occurs when the amount of gas handled by the blower is controlled by the opening degree of the vanes, and to effectively control the operating air volume with remarkable efficiency. This has practical effects such as a simple configuration and a form in which the shaft power can be reduced, and energy saving effects can be easily realized.

[Brief explanation of the drawing]

1 and 2 are a vertical sectional view and a side view of a conventional example, FIG. 3 is a vertical sectional view of an embodiment of the present invention, FIG. 4 is a side view thereof, and FIG. 5 is a longitudinal sectional view of another embodiment. side view,
FIG. 6 is a relationship diagram between air volume and low frequency noise level. 1... Impeller, 2... Suction port, 3... Casing, 4... Suction sleeve, 5... Vane, 6... Shaft, 7
...Partition plate, 8...Guide, 10...Blower main shaft.

Claims (1)

[Claims for Utility Model Registration] (1) In an air volume control device in which a plurality of movable blades 5 are installed around the suction port 2 and the angle of the movable blades 5 is changed to control the amount of gas handled by the blower, An air volume control device for a blower, characterized in that a partition plate 7 is provided in the radial direction on the inner peripheral side of the movable blade 5, at a position upstream from the suction port 2 and downstream from the movable blade 5. (2) The movable blade 5 is rotatably provided with a shaft 6, and the shaft 6 is connected to the blower main shaft 1.
1. The air volume control device according to claim 1, which is arranged in parallel with the Utility Model Registered Claim. (3) The air volume control device according to claim 1 or 2, wherein the partition plate 7 is provided at a predetermined position on the circumference. (4) Utility model registration claim 1, in which the partition plates 7 are arranged in plural pieces at predetermined intervals.
The air volume control device according to item 1 or 2. (5) The utility model according to any one of claims 1 to 3, wherein the partition plate 7 is installed in a conical guide 8 formed in the suction port 2. Air volume control device.