WO1998027341A1

WO1998027341A1 - New structure of roots blower or roots vacuum pump with a multi-lobes impeller and a reverse flow unit

Info

Publication number: WO1998027341A1
Application number: PCT/CN1997/000121
Authority: WO
Inventors: Shanglu Wan; Yuxin Gao; Yusheng Niu; Shihua Liu
Original assignee: Zhangqiu Blower Factory, Shandong
Priority date: 1996-12-16
Filing date: 1997-10-30
Publication date: 1998-06-25
Also published as: CN2301559Y

Abstract

This invention relates to a new structure of Roots blower or Roots vacuum pump with a multi-lobes impeller and a reverse flow unit, the lobes of the impeller having a top width and according with the following equation: η1 ≥ α - β1 + ε1, η2 ≥ α - β1 + ε1 and υ ≥ η1 + ν + η2. The intaking gas of the reverse flow, the lower pressure entering gas and the higher pressure discharging gas are separated from each other and are not interference with each other, thereby reducing the noise and increasing the cooling efficiency. The lobes are provided with labyrinth recesses on its top along its wide direction, resulting in lower radial leakage of the gas and more receiving of particles in the air without wearing between lobes and the surface of the housing.

Description

Multi-lobe impeller roots blower with countercurrent device, roots vacuum pump structure Technical field

The invention relates to a structure of a roots blower and a roots vacuum pump, and in particular to a structure of a multi-lobe impeller roots blower and a roots vacuum pump with a countercurrent device.

Background technique

The structure and operation diagram of the existing Roots blower and Roots vacuum pump are shown in Figure 1. It includes a pair of parallel shafts 1, and a two-blade impeller ⁴ is mounted on the parallel shaft 1, and a synchronous gear mounted on the shaft end is used. The two impellers 4 are meshed with each other for reverse rotation. The two parallel shafts 1 and the impeller 4 are installed in a casing 3, and the casing 3 is provided with a casing inlet 2 and a casing exhaust port 7 at the upper and lower ends, respectively. When the impeller 4 rotates in the casing 3, the right tip point of the blade top 17 located at the exhaust port 7 is Q. When the Q point is located at the end point T of the casing working surface, it is closed by the impeller 4 and the casing 3. The volume V, whose pressure is the intake pressure Pj. Once the Q point deviates from T and a gap appears, the high-pressure gas at the casing exhaust port 7 is compressed at a pressure P ₂ through the gap between Q and T and compresses the volume V, and generates a backflow impact on the impeller 4 to exhaust. Due to the periodic pulsation, the flow brings greater noise and vibration. With the development of production, the required exhaust pressure P _{2 is} increasing day by day, which not only makes the noise impact more serious, but also the temperature of the high-pressure exhaust gas is greatly increased, which seriously threatens the normality of Roots blowers and Roots vacuum pumps. Operation and working life have thus become long-standing unsolved problems at home and abroad.

Since the 1970s, people have made a lot of explorations from improving the structure of the body to reduce the body's hydrodynamic noise. The main measure is to try to exhaust a part of the high-pressure gas (or high-pressure exhaust before the gap between (5, T) appears. ) Guide the volume V in advance to pre-boost, so that the pressure of V increases to P ₃ , and the differential pressure between P ₃ and P ₂ is minimized to reduce backflow impact and noise.

In the mid-seventies, DRESSER Corporation introduced the Roots-Weiss blower with Whispair, which is the first product in the world to adopt countercurrent boost noise reduction measures. At the same time, a Roots-Weiss vacuum pump with exhaust gas venting to the atmosphere is also introduced. Its countercurrent inlet port is directly connected to the atmosphere. The differential pressure of the negative pressure of the vacuum pump by cold air is directly introduced into V to generate countercurrent boost noise reduction and countercurrent cooling. Dual effect. However, since the impeller 4 is of a two-bladed type, the counter-current intake port is very close to the exhaust port. Therefore, once the counter-current intake port is snoring, the gap between 0 and T will soon be exposed to high-pressure exhaust. Gas backflow interference, However, it cannot fully utilize its noise reduction and cooling performance. To this end, the author of this paper filed an application for an invention patent in 1995 ^ 12, | ί, 川 '|: i Zhuanli Bureau, application number: 95235177.3, Name: Roots blower with countercurrent device, new structure of Roots vacuum pump. The purpose is to overcome the shortcomings of the two-leaf roots blower and the vacuum ^ counter-current inlet port that is too close to the exhaust gas, and adopt a two-leaf wide-tip tip impeller profile to move the counter-current inlet port inward, which can extend [^ The process of counter-current boosting and counter-current cooling to improve the efficiency of noise reduction and cooling, but still cannot completely eliminate the interference of high-pressure exhaust on counter-current intake.

In the early 1980s, the Uenozawa Iron Works introduced the AR.I type Roots blower and Roots vacuum pump, using a three-blade impeller and the aforementioned counter-current device, so that the counter-current intake port works along the shell to enter the air intake. II moves 30 ° inward, which improves the counterflow effect, but because the impeller profile is a commonly used triple porphyrin arc profile, the effect of high pressure exhaust on the countercurrent intake cannot be eliminated.

Disclosure of invention

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a kind of Roots blower and Roots vacuum pump structure with a multi-lobe impeller, so that the counter-current intake air is isolated from the squeezing pressure, so that S landing strengthens noise reduction and cooling effects.

Multi-lobe impeller Roots blower and Roots vacuum pump structure with countercurrent device provided by Mu Invention include Roots blower, Roots vacuum pump and countercurrent supply device, please refer to i? I2, m3 and Figure 4, the countercurrent supply device welcomes The counter-current inlet hole for passing air into the casing through the counter-current intake pipe is provided on the casing, which is characterized in that the multi-blade impeller is adopted in the sacral impeller, and the top of the blade is provided with a top width, which is located in the casing The "I" center angle formed by the axis between the starting point s of the casing and the upper point u of the counter-current intake port on the casing working surface is the point τ at the end of the casing working surface and the counter-current intake port The central fish formed by the axis at the point of intersection w at the upper part of the casing is γ ₂ , and the top angle formed by the top width of the blade to the axis is (i, the center line of two adjacent blades). The central angle formed by the center of the axis is α, the upper tip point of the blade width at the countercurrent channel is M, and the lower tip point is N> As shown in Figure 3, when the M point and the U point are combined, it is in the countercurrent intake Just before entering the volume through the gap between M, U] The critical position for pre-pressurization, this is located at the intake end The center angle formed by the axial center between the right tip point P of the blade top width and the starting point S of the casing working surface is the closing angle of the intake end, and the right tip point P of the blade top width of the inlet end is to the left of point S. The sealing angle ε of the P and S gaps at the inlet end is determined as a negative value. It was found from the actual DVJ-type Webster vacuum pump of DRESSER Company: up to-15. Up and down, it is recommended that ε ^ 0 ~-10 ° The top width of the top of the blade on the impeller is B i, The diameter of the impeller is D, so the center angle corresponding to ^ is 0 _| = 2 · arcsin B! / D. To ensure that the counter-current intake air does not interfere with the low-pressure intake air of the casing inlet, it should meet:

γι≥-βι + ει (1)

In the same way, in FIG. 4, the lower tip point N of the blade top width of the counterflow channel coincides with the lower intersection point W of the counterflow inlet channel on the working surface of the casing, that is, the counterflow inlet is about to be completed, and At the critical position that does not interfere with the high-pressure exhaust of the casing exhaust port, at this time, the center angle formed by the right sharp point Q of the blade tip width at the exhaust end and the end of the casing working surface τ on the axis is the exhaust. End closing angle ¾, Q point is to the left of τ point, that is, Q and T gaps exist, the exhaust end closing angle ε _{2 is} set to a negative value, recommended = 0 ~-10 °, to ensure the counter-current intake of the counter-current intake port Does not interfere with the high-pressure exhaust of the casing exhaust port.

2 ≥ α-βι + ε ₂ (2)

conditions of.

Let the included angle between the starting point S of the working surface of the casing and the vertical axis passing through the axis of the working surface of the casing be, the angle between the end of the working surface of the casing and the axis and the vertical axis of the working surface of the casing passing the axis is δ ₂ . Usually δ, and δ ₂ are about 10 °. The central angle formed by the counter current inlet channel width UW to the axis is μ, usually μ is above and below 20 °, then the central angle e isc + s! + Ss formed by the working surface of the housing when facing the axis, when

θ> γι + μ + γ ₂ (3) then the above formulas (1) and (2) are guaranteed to be realized simultaneously from the structure, so that the countercurrent intake and the low-pressure intake of the casing inlet and the casing The high-pressure exhaust gas at the exhaust port is isolated from each other without interfering with each other, and the purpose of the present invention is achieved. That is, the multi-lobe impeller Roots blower and Roots vacuum pump structure provided by the present invention should meet the conditions at the same time:

γι>-βι + S!

γ ₂ >-βι + ε ₂

θ> γι + μ + γ ₂

Brief description of the drawings

The invention is further described below with reference to the drawings and embodiments.

Figure 1 is a schematic diagram of the structure and operation of the existing Roots blower and Roots vacuum pump;

FIG. 2 is a schematic structural diagram of an embodiment of the present invention (only the right half is shown, and the left half is symmetrical with the right half, the same applies hereinafter); FIG. 3 is a schematic diagram of the operation structure of the air intake part of FIG. 2;

Figure 4 is a schematic diagram of the operation structure of the exhaust part of Figure 2;

FIG. 5 is a schematic diagram of a preferred embodiment of the working process of the present invention;

FIG. 6 is a schematic diagram of a preferred embodiment of the working process of the present invention;

FIG. 7 is a structural schematic diagram of a wide-blade labyrinth groove on the top of the impeller according to a preferred embodiment of the present invention; and FIG. 8 is a schematic structural diagram of a five-lobed impeller according to another embodiment of the present invention.

1-parallel axis, 2-case air inlet, 3-case,

4 an impeller, 5― blade, 6-- blade,

7—chassis exhaust port, 8—counter current supply device, 9 — counter current inlet pipe,

10— countercurrent inlet port, 1 1—motor, 1 3—intake muffler,

14 a exhaust muffler, 15 — Roots blower, Roots vacuum pump,

16-exhaust pipe, 17 — vanes, 1 8 — intercooler,

1 9 a labyrinth slot, 20 — return muffler, 21 — intake filter;

Q —― Right point of blade tip width S — Starting point of working surface of casing

T-End of working surface of cabinet V, 1 Volume

P, P ₂ P ₃ — pressure U — counter current inlet hole working on the casing w — counter current inlet hole lower intersection of the casing working surface

γ _ι — the central angle formed between the two points on the axis

γ ₂ -Τ, W is the center angle formed by the two axes

[3, a central angle formed by the blade tip width to the axis

α-the centerline of the centerline of two adjacent blades against the axis ½

Ρ-right tip of blade tip width at inlet

Ρ '-the left tip of the blade tip width at the inlet

Ｍ一 At the tip of the blade width of the counter-current inlet hole

Ν-Located at the tip of the blade tip width of the countercurrent inlet hole

Q-Wide right sharp point of the blade at the exhaust end

Q'—Top wide left tip of blade on exhaust side

ε, a closing angle of the inlet

Exhaust end closing angle The best solution to realize the present invention

As an embodiment of the structure of the multi-lobe impeller Roots blower and Roots vacuum pump with a countercurrent device according to the present invention, the structure is schematically shown in FIG. 2, FIG. 3, FIG. 4, FIG. 7 and FIG. 8. The structure of the multi-lobe impeller Roots blower and Roots vacuum pump includes a Roots blower, a Roots vacuum pump, and a counter-current supply device. The counter-current supply device 8 feeds the counter-current intake port 10 to the casing 3 through the counter-current intake pipe 9. It is arranged on the casing 3, and the center angle formed by the axis between the starting point S of the casing working surface of the casing air inlet 2 and the upper intersection point U of the counter-current intake hole 10 on the casing working surface is _γι. The center angle formed between the end point T of the working surface of the casing located at the casing exhaust port 7 and the lower intersection point W of the counter-current intake port 10 on the working surface of the casing is γ ₂ , and the center angle of the multi-leaf impeller is The top width of the top of the blade is B !, B, and the center angle formed by the axis is α. The angle between the centerlines of two adjacent blades of the multi-blade impeller is located on the top width of the blade of the counter-current inlet hole 10. The sharp point is M, and the lower sharp point is N. As shown in Figs. 3 and 4, when M and U are coincident, The center angle formed by the top center of the blade 5 at the air inlet end and the right sharp point P and the starting point S of the casing working surface against the axis is the air inlet end closing angle. When the points N and W coincide, The central angle formed by the top width between the sharp point Q and the end point of the working surface of the casing on the axis is the exhaust end closed angle ε ₂ , and the angles should simultaneously satisfy>-β, + ει and? ₂ > α- Pt + S conditions; when the number n of multi-blade impeller blades is 3, 4, 5, or more, the center angle a between two adjacent blades should be 120 °, 90. , 7 2 ° or 360 ° / 11. When the multi-blade impeller is a three-blade type, that is, the number of blades of the multi-blade impeller is n = 3, see FIG. 3 and FIG. 4, at this time 7 ^ 72 = 90 °, and the center angle o between the two blades is 120 °, Take in and exhaust end closing angle s!-^ Z-10 °, you must ensure that the top width of the blade top of the impeller is opposite to the center angle β [15 ° ~ 25 °, this blade has a wider three-blade top width The profile can satisfy the aforementioned conditional expressions (1), (2), and (3) at the same time, so that the counter-current intake air and the low-pressure intake air of the casing air inlet 2 and the high-pressure exhaust air of the casing exhaust port 7 are mutually Requirements for isolation without interference. When the number of blades of the impeller η = 4, see Figures 3 and 4, Θ = 200 °, the center angle of the countercurrent inlet port 10 μ = 20 °, then _γι = γ ₂ = 90 ° can fully guarantee the aforementioned conditional expression ( The requirements of 1), (2) and (3) are realized in structure. For four-leaf and more than four-leaf multi-leaf type impellers, impeller profiles with no blade top width can be used.

The multi-lobe impeller Roots blower with a countercurrent device and the impeller of the Roots blower and Roots vacuum pump 15 in the Roots vacuum pump structure adopt a large blade top width, which reduces radial leakage under high pressure and improves operating efficiency. Extremely advantageous. Especially when the working air intake and countercurrent air intake contain relatively serious fine dust particles, because B is wider, it is resistant to accidents in which the dust particles can not work due to wear on the top of the blade. To a great protection effect, as a better embodiment, as shown in FIG. 7, a labyrinth groove 19 is provided on the top width of the top of the blade of the multi-blade impeller, which can further reduce radial leakage and improve operating efficiency. In addition, when the dust content is serious, the labyrinth groove 19 on the top of the impeller can be used as a dust collection tank to store dust particles in the working air intake and counter-current air intake to prevent wear on the top of the blade and the working surface of the casing. With the rotation of the impeller, the dust particles contained in the labyrinth groove 19 on the blade top width can be transported to the casing exhaust port 7 and discharged with the airflow. FIG. 8 is a schematic structural diagram of a five-leaf impeller profile according to the present invention. Its working principle is the same as above, and it will not be repeated here.

As the preferred embodiments of the multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to the present invention, as shown in FIG. 3, FIG. 4, FIG. 5, FIG. 7 and FIG. Atmospheric Roots vacuum pump, its countercurrent supply device 8 can directly communicate with the atmosphere, and the atmosphere is used as the source of countercurrent intake air. The countercurrent inlet pipe 9 enters the casing 3 through the countercurrent inlet port 10, and the Roots vacuum pump 15 passes The airflow discharged from the exhaust port 7 of the cabinet can be directly discharged into the atmosphere, or can be discharged into the atmosphere through the exhaust pipe 16 through the exhaust muffler 14 to reduce environmental noise pollution. As a more preferred embodiment, when the countercurrent supply device 8 obtains a countercurrent intake airflow from the atmosphere, it is preferable to enter the human body 3 through the intake muffler 13 with the filter 21. Because the low temperature atmosphere has a large natural differential pressure on the low negative pressure of the roots vacuum pump inlet, it can achieve the dual effects of the most economical countercurrent boost noise reduction and countercurrent cooling.

As a preferred embodiment of the multi-lobe impeller Roots blower and Roots vacuum pump with a countercurrent device according to the present invention, as shown in FIG. 2, FIG. 3, FIG. 4, FIG. 6, FIG. 7 and FIG. A Roots blower with positive air pressure and a Roots vacuum pump whose exhaust gas is not connected to the atmosphere. The countercurrent supply device 8 can communicate with the exhaust end 7 of the Roots blower and Roots vacuum pump 15, and the countercurrent supply is provided by high pressure exhaust As a more preferred embodiment, when the countercurrent supply device 8 obtains air from the exhaust of the Roots blower and Roots vacuum pump 15, it is preferably passed through the intercooler 18, or the return muffler 20, or a series of intercoolers. The cooler 18 and the return muffler 20 cool and mute the gas through the counterflow inlet pipe 9 and enter the casing 3 through the counterflow inlet hole 10 to achieve the dual effects of countercurrent boost noise reduction and countercurrent cooling.

The structure of the multi-lobe impeller Roots blower and the Roots vacuum pump with the counter-current device of the present invention adopts the multi-lobe impeller, and the setting of the counter-current device satisfies the corresponding conditions, and the mutual interference between the counter-current intake and the high-pressure exhaust and the low-pressure intake is fully isolated In order to obtain the best countercurrent effect, significantly enhance the noise reduction and cooling effect, ensure that the Roots blower and Roots vacuum pump run efficiently and improve the working life.

Claims

Rights request

1. A multi-lobe impeller Roots blower with a reverse flow device and a Roots vacuum pump structure, including a Roots blower, a Roots vacuum pump, and a counter-current supply device. The air inlet hole is set on the casing, which is characterized in that: the impeller is a multi-lobe impeller, and the top of the blade is provided with a top width. The center angle formed by the intersection point U on the working surface and the axis is ah! The central angle formed between the end point T of the working surface of the casing at the exhaust port and the lower intersection point W of the countercurrent inlet port on the working surface of the casing is γ ₂ , and the top width of the top of the blade is against the axial center. The center angle formed is that the center angle formed by the centerline of two adjacent blades to the axis is α, and the upper point of the blade width at the countercurrent inlet port is M, the lower point is N, and the countercurrent inlet port pair The central angle formed by the shaft center is μ, and the central angle formed by the working surface of the casing is θ. When the points M and U coincide, the top right point P of the blade at the inlet end works with the casing The center angle formed by the axis center between the surface starting points S is the closing angle of the inlet end _ει . When the points N and W coincide, it is located between the right tip point Q of the blade tip width at the exhaust end and the end point T of the working surface of the casing. The center angle formed by the shaft center is the exhaust end closed angle ε ₂ , and each angle should satisfy the following relationship at the same time:

γι ≥ α-βι + ει

γ ₂ ≥-βι + ε ₂

θ> γι + μ + γ ₂

2. The multi-lobe impeller Roots blower and the Roots vacuum pump structure with a countercurrent device according to claim 1, wherein the number of multi-lobe impeller blades η is 3, 4, 5, or more, two The center angle α between adjacent blades is 120 °, 90 °, 72 ° or 360 η.

3. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 2, wherein the multi-lobe impeller is a three-lobe type, that is, the number of multi-lobe impeller blades η = At 3 o'clock, the center angle βm formed by the top width of the blade top of the impeller and the axis is 15 °-25. When the number of blades of the multi-leaf impeller is 11 ≥ 4, the width of the leaves at the top of the blades can be 0.

4. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 1 or 2 or 3, characterized in that a labyrinth is set on the top width of the top of the blade of the multi-lobe impeller. groove.

5. A multi-lobe impeller roots blower with a countercurrent device according to claim 1 or 2 or 3, roots The structure of the vacuum pump is characterized in that the Roots blower and the Roots vacuum pump are Roots vacuum pumps that directly pass into the atmosphere, and the countercurrent supply device can directly communicate with the atmosphere, and the countercurrent intake air is directly provided by the atmosphere.

6. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 4, characterized in that the Roots blower and Roots vacuum pump are Roots vacuum pumps whose exhaust gas directly flows into the atmosphere. Its countercurrent supply device is in communication with the atmosphere, and its countercurrent supply is directly provided by the atmosphere.

7. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 1 or 2 or 3, characterized in that the countercurrent supply device is provided with an intake air filter and an intake muffler.

8. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 4, wherein the countercurrent supply device is provided with an air intake filter and an air muffler.

9. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 1 or 2 or 3, characterized in that said Roots blower and Roots vacuum pump are Roots blower and exhaust The Roots vacuum pump not connected to the atmosphere, the countercurrent supply device is in communication with the Roots blower and the exhaust end of the Roots vacuum pump, and the countercurrent supply is provided by high-pressure exhaust.

10. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 4, wherein the Roots blower and Roots vacuum pump are Roots blowers and the exhaust gas is not connected to the atmosphere. In the roots vacuum pump, the countercurrent supply device is in communication with the exhaust end of the roots blower and the roots vacuum pump, and the countercurrent supply is provided by high-pressure exhaust.

11. The structure of the multi-lobe impeller Roots blower and Roots vacuum pump with a countercurrent device according to claim 9, wherein the countercurrent supply device is provided with an intercooler.

12. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 10, wherein the countercurrent supply device is provided with an intercooler.

13. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 9, characterized in that the countercurrent supply device is provided with a return muffler.

14. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 10, wherein the countercurrent supply device is provided with a return muffler.

15. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 9, wherein the countercurrent supply device is provided with an intercooler and a return muffler connected in series.

16. The multi-lobe impeller Roots blower and Roots vacuum pump structure with a countercurrent device according to claim 10, wherein the countercurrent supply device has an intercooler and a return muffler connected in series.