JPS6375377A - Roots blower - Google Patents

Abstract

PURPOSE:To make the pitch and level of discharge pulsation reducible, by dividing each vane of paired rotors into two parts in the axial direction, and partitioning off the interval with a partition plate, while shifting each rotational phase of these vanes on both sides of the partition plate to some extent mutu ally. CONSTITUTION:Two vanes of rotors 5 and 6 are constituted of divided vanes 5a, 5b, 6a and 6b halved in the turning shaft direction of these rotors 5 and 6, and a partition plate 7 supported by a casing 1 is set up between these divided vanes 5a, 5b and 6a, 6b. These vanes 5a, 6a and 5b, 6b engaged with one another are supported on a turning shaft so as to make each differ as far as 90 degrees in rotational phase, so that phase, where pulsating pressure of the gas discharged out of both sides of the partition plate 7 is varied, is shifted to some extent, and since variations in the pulsating pressure interfere with each other, the pitch and the level are halved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a roots blower used to suck or compress gas to form a vacuum or pressure source.

(Prior Art) An example of a conventional roots blower of this type is shown in FIGS. 5 and 6.

A pair of rotors 02 having a cocoon-shaped cross section each having two or three vanes 01 are arranged in parallel with each other so that the phases of the respective vanes O1 are shifted from each other, and housed in a casing 03. 02 are rotated in opposite directions via synchronized floats, the gas sucked in from the suction port 04 is compressed and discharged from the discharge port 05.

(Frontage point to be solved by the invention) In the above-mentioned conventional Roots blower, the discharge pressure is the seventh
As shown in the figure, it pulsates and noise is generated accordingly.

This pulsation is uniquely determined by the number of vanes 01 and the rotation speed of the rotor 02, and can be suppressed if the number of vanes 01 can be increased infinitely, but due to structural limitations, the number of vanes 701 should be at most 3M for practical purposes. is the limit. Also,
It was also proposed to set each vane 01 back by 1, but this also resulted in a complicated structure, and there was a limit to the reduction of 11 tones.

(Means for Solving the Problems) The present invention was developed to solve the above problems, and its gist is to move the vanes of a pair of rotors in the direction of the rotor's rotational axis. The roots blower is characterized in that the adjacent divided vanes are partitioned by a partition plate, and the phases of the adjacent divided vanes are shifted from each other.

(Function) Since the present invention has the above-mentioned configuration, the gas compressed by the divided vanes partitioned by the temporary partitions is discharged alternately with a time difference, thereby reducing the pinch and level of pulsation.

(Implementation (511)) One embodiment of the present invention is shown in FIGS. 1-4.

In Figures 1 to 3, 1 is a casing, 2 is a suction port, 3 is a discharge port, 5.6 is a rotor, and 7 is a partition plate. It is divided into two parts in the axial direction to form divided vanes 5a and 5b, and the phases of these divided vanes 5a and 5b are shifted by 90 degrees from each other. Similarly, the two vanes of the rotor 6 are each divided into two in the direction of the rotation axis of the rotor, and the divided vanes 6a
, 6b, and these parts;';+I vane Ga, 6
The phases of b are shifted by 90° from each other. The rotors 5 and 6 are housed in the casing 1 in a parallel arrangement such that the divided vanes 5a and 68 and the divided vanes 5b and 6b mesh with each other. Further, a temporary partition 7 is arranged to be located between the divided vanes 5a and 5b, and between 6a and 6b.
In the figure, on the right side are divided vanes 5a and 6 that mesh with each other.
A and the inner surface of the casing 1 form a first displacement chamber 8, and on the (lh side of the partition plate 7, that is, on the left in FIG. A second displacement chamber 9 is formed.A suction port 2 and a discharge port 3 are provided in the casing 1 so as to open into the first and second displacement chambers 8 and 9, respectively.

When the pair of rotors 5.6 are rotated in opposite directions via synchronous floats (not shown), the divided vanes 5a
and 5b and the divided vanes 6a and 6b, the ρ phases are shifted by 90 degrees from each other, so gas is alternately sucked from the suction port 2 into the first displacement chamber 3X8 and the second displacement chamber 9, where it is compressed. After that, the liquid is discharged from these displacement chambers 8 and 9 alternately through the discharge port 3. Therefore, the discharge pressure changes as shown in Fig. 4, and as is clear from Fig. 7, it becomes about half when the pulsating pressure is fluctuating, and the pitch of the pulsating pressure also becomes about half. The noise generated from this Roots blower is also reduced by 111 times.

In the above embodiment, the phases of the indirect segmented vanes 5a and 5b and 68 and 6b separated by the partition plate 7 are shifted by 90 degrees, but the phase shift angle may vary depending on the leaf structure of the vanes. Of course.

(Effects of the Invention) In the present invention, the vanes of a pair of rotors are each divided in the direction of the rotational axis of the rotor, the adjacent divided vanes are partitioned by a partition plate, and the phases of the adjacent divided vanes are mutually adjusted. Because of the offset, it is possible to significantly reduce the level and pitch of the pulsating pressure of the gas discharged from the discharge port.Thus, even if the amount of gas discharged from the Roots blower is the same, the noise generated from this can be greatly reduced in the low range. can.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view, and FIGS. 2 and 3 are respectively
FIG. 4 is a cross-sectional view taken along the n-line and mm-line, and is a diagram showing changes in discharge pressure. 5 to 7 show an example of a conventional blower, in which FIG. 5 is a vertical cross-sectional view, and FIG.
FIG. 7, a cross-sectional view taken along the line l-Vl, is a diagram showing changes in discharge pressure. Casing: -1, Suction port: 2, Discharge port: 3
, Loku 5.6.1 Split vane 5a, 5b, (
ia, 6b.

Claims (1)

[Claims] A Roots blower characterized in that the vanes of a pair of rotors are each divided in the direction of the rotation axis of the rotor, the adjacent divided vanes are partitioned by a partition plate, and the phases of the adjacent divided vanes are shifted from each other.