CN201982296U

CN201982296U - Housing of Roots blower

Info

Publication number: CN201982296U
Application number: CN2011200854850U
Authority: CN
Inventors: 高进
Original assignee: ZHEJIANG TONGYUAN BLOWER Co Ltd
Current assignee: ZHEJIANG TONGYUAN BLOWER Co Ltd
Priority date: 2011-03-29
Filing date: 2011-03-29
Publication date: 2011-09-21
Anticipated expiration: 2021-03-29

Abstract

The utility model provides a housing of a Roots blower. The inner wall of the housing of the Roots blower is formed by intersecting two cylindrical surfaces respectively taking a rotor shaft as the axis and the crown elevation of a blade (11) of a rotor (9) as the radius; an air entry (4) and an air outlet (8) of the Roots blower are respectively arranged at the intersected part of the two cylindrical surfaces of the housing, whereas the inner wall of the housing is provided with a return tank (12) on the cylindrical surfaces at both sides of the air outlet rotating to the rotor in the opposite direction; and the return tank is a concave surface on the inner wall of the housing (3), wherein the length of the concave surface is less than that of the rotor, and the central angle included between the widest part of the concave surface and the outermost edge of the area of the air entry is not less than the central angle included between two adjacent blades. In the housing of the Roots blower provided by the utility model, the width of the return tank on the inner wall is almost equal to the entire length of the rotor. Compared with a design that a plurality of narrow slots serve as the return tanks, an airflow channel completely does not have the abrupt change, so that the backflow is more smooth and the noise is lower.

Description

The Roots blower casing

Technical field

The utility model relates to a kind of structure of Roots blower casing, especially casing inner wall, belong to pump technical field in the mechanical engineering.

Background technique

Roots blower is a kind of machinery that is used for conveying gas, and its structure comprises the air cavity of being made up of casing and front and back wallboard, and suction and exhaust ports is arranged on the casing.The axle of pair of parallel is installed between the wallboard of front and back, and diaxon is respectively driving shaft and driven shaft, and diaxon connects with intermeshing synchromesh gear outside wallboard.The rotor of spur gear shape is housed respectively on the diaxon in the air cavity, and two rotors also are intermeshing.Casing inner wall is by respectively with two rotor coaxials and to rise with blade be that two cylndrical surface of radius are intersected and to be formed.Driving shaft drives driven shaft through synchromesh gear during work, and diaxon is rotated relatively, and rotor is then carried the gas of intakeport to relief opening.Rotor is to the conveying of gas, be the gas that is comprised when relief opening rotates from intakeport by the space between the adjacent blades (swept volume) in the rotor, gas when sealing is nipped mouthful at two rotor engaged places in this space is extruded from relief opening and is realized, so the pressure of relief opening is higher than the gas pressure in the space of no show relief opening.The Roots blower casing of Shi Yonging in the past, except that the suction and exhaust ports zone, its inwall and rotor blade top match, in other words conj.or perhaps sealing.Therefore near the blade top rotates to relief opening, make instantaneous that swept volume is connected with relief opening, because of gas that elevated pressures is arranged with backflow at a high speed, at this moment the pressure in the swept volume raises suddenly, generation huge impact noise.

Summary of the invention

At this deficiency, the utility model is exactly that a kind of Roots blower casing that makes Roots blower reduce noise will be provided.

The Roots blower casing that the utility model provides, its inwall is respectively that axle, rotor blade rise with the rotor shaft by two is that the cylndrical surface of radius is intersected and to be formed, the intakeport of Roots blower and relief opening are separately positioned on the intersection, two cylndrical surface of casing, but casing inner wall offers back flash on the cylndrical surface of both sides at relief opening in the other direction to rotor rotation, and said back flash is the concave surface that length is not less than the folded central angle of adjacent two blades on the casing inner wall with the folded central angle in the outer in interior, the widest position and intakeport zone in rotor length.

The Roots blower casing that the utility model provides, casing inner wall has the back flash of linking up between the swept volume that exhaust oral region and blade isolate, when making vane tip rotate to the back flash zone, the relief opening pressurized gas can gently be back to swept volume by back flash, have eliminated vane tip and have arrived near the problem that makes instantaneous just the backflow suddenly that swept volume is connected with relief opening the relief opening and cause sonic boom generation noise.Thereby reduced the backflow noise, made the total noise of centrifuge level reduce.Simultaneously, use the utility model and also make the suction and discharge process obtain buffering, i.e. the suction and discharge process of mild blower fan, volumetric efficiency has improved 3 ~ 8 %, has finally reduced energy consumption.

The Roots blower casing that the utility model provides, the width of back flash almost is the whole length of rotor on the inwall, and with the design of some narrow grooves as back flash, has not had the unexpected variation of air-flow path fully, makes that backflow is milder, noise is lower.

The shape of said back flash outermost side is the bent limit of shrinking to the centre gradually, promptly is the middle curve shape that goes out to intakeport one side point, makes the backflow terminal procedure level and smooth, further reduces noise.

Description of drawings

Fig. 1 is a Roots blower external structure schematic representation; Among the figure: 1-gear-box, 2-rear wall plate, 3-casing, 4-intakeport, 5-front wallboard, 6-front cover, 7-driving shaft, 8-relief opening;

Fig. 2 be the utility model one embodiment partly cut open figure; Among the figure: 2-rear wall plate, 3-casing, 4-intakeport, 6-front cover, 7-driving shaft, 8-relief opening, 9-rotor, 10-driven shaft, 11-blade, 12-back flash;

Fig. 3 is that the part of Fig. 2 is overlooked and cutd open figure; Among the figure: 3-casing, 5-front wallboard, 6-front cover, 7-driving shaft, 12-back flash.

Embodiment

One Roots blower as shown in Figure 1, 2, comprise the air cavity that casing 3, front wallboard 5, rear wall plate 2 are formed, on the inherent same horizontal plane of casing a pair of rotor shaft is installed abreast, wherein one be driving shaft 7 another be driven shaft 10, synchromesh gear in the gear-box 1 between the main driven shaft outside rear wall plate connects, and front wallboard also has the metalworking coolant of front cover 6 in order to stuffing box bearing outward.The straight type blade that has three five equilibriums to be provided with on the rotor, the blade on two rotor shafts mesh installation mutually as spur gear.Casing inner wall is to be axis, to rise crossing formation the in two cylndrical surface that (being blade top margin and axle center spacing) is radius with blade with two rotor shafts, and two intersections are provided with intakeport 4 and relief opening 8 respectively up and down.Be provided with back flash 12 in the relief opening both sides, promptly a part of cylinder that changes from the contrary blade of relief opening side on according to the sense of rotation of axis in the cylndrical surface is provided with concave surface, on this concave surface axial direction the width two ends blade according to axial direction in the width two ends, and the central angle between shared cambered surface biggest place of this concave surface and the vertical surface is 60 °.The projection of back flash on the said casing inner wall on plan view as shown in Figure 3, its by limit of intakeport one side be in the middle of the curve that goes out of point.Rotate to relief opening one side and with the vertical surface angle during less than 60 ° at blade like this, be communicated with between relief opening and this blade and the swept volume that previous blade is enclosed, the pressurized gas that relief opening was communicated with reflux to swept volume.Therefore, use the utility model and can provide that a kind of volumetric efficiency height, reliability height, noise are little, the Roots blower of compact structure.

Claims

1. Roots blower casing, its inwall is respectively that axle, rotor blade rise with the rotor shaft by two is that the cylndrical surface of radius is intersected and to be formed, the intakeport of Roots blower and relief opening are separately positioned on the intersection, two cylndrical surface of casing, it is characterized in that casing inner wall offers back flash on the cylndrical surface of both sides at relief opening in the other direction to rotor rotation, said back flash is the concave surface that length is not less than the folded central angle of adjacent two blades on the casing inner wall with the folded central angle in the outer in interior, the widest position and intakeport zone in rotor length.

2. Roots blower casing as claimed in claim 1, the shape that it is characterized in that said back flash outermost side are the bent limits of shrinking to the centre gradually, promptly are the middle curve shapes that goes out to intakeport one side point.