Positive pressure or negative pressure Roots blower structure with reverse flow ports on two sides pointing to exhaust port

Abstract

The utility model relates to the technical field of Roots blowers, in particular to a positive-pressure or negative-pressure Roots blower structure with countercurrent ports at two sides pointing to an exhaust port, which comprises a casing, a rotor, a countercurrent chamber and countercurrent ports, and two groups of countercurrent ports pointing to the exhaust port are distributed on two sides of the casing close to the exhaust port. After exhaust gas of the positive pressure Roots blower is cooled by the heat exchanger (normal-temperature and normal-pressure air is introduced by the negative pressure Roots blower), the exhaust gas enters the machine shell from the reverse flow port in the direction pointing to the exhaust port, and when the exhaust port is opened, high-pressure gas in the area between the machine shell and the rotor can directly impact backflow of the exhaust port along the reverse flow port. On the basis that the advantages of a conventional countercurrent cooling Roots blower are kept, the shaft power, the exhaust temperature and the exhaust flow pulsation of the countercurrent cooling Roots blower can be reduced, meanwhile, due to the fact that a countercurrent opening is close to an exhaust opening, flow and leakage flow participating in internal circulation are small, flow and pressure parameters can replace an existing conventional countercurrent cooling blower, and energy conservation, noise reduction and vibration reduction are achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to roots blower technical field especially one kind is directed to the positive pressure or negative pressure roots blower structure of two sides counter current port pointing exhaust port. BACKGROUND

[0002] Roots blower has the advantages of simple structure, easy to use and maintain, and stable flow when system resistance changes. However, the gas compression degree in the roots blower is low, the efficiency is low, the power consumption is large, there is a large backflow impact when exhausting, the pneumatic noise and vibration are large. When the positive pressure roots blower adopts the counterflow cooling structure, the high pressure and low temperature counterflow gas can be used to increase the pressure of the element volume chamber between the casing and the rotor, reduce the pressure difference on both sides of the rotor when the exhaust port is opened, reduce the backflow impact and exhaust temperature of the exhaust gas flow, and the negative pressure roots blower also adopts a similar counterflow structure to introduce normal temperature and pressure air, which can also reduce the pressure difference on both sides of the rotor when the exhaust port is opened, reduce the backflow impact and exhaust temperature of the exhaust gas flow, reduce the gas pulsation, reduce the noise of the roots blower, improve the pressure ratio of the roots blower conveying medium, and widen the application range of the roots blower. However, the power of the conventional counterflow roots blower does not change much compared with the roots blower without counterflow, so reducing the power consumption of the counterflow cooling roots blower and further reducing the noise are of great significance to widening the application field of the counterflow cooling roots blower and realizing energy saving and emission reduction. The counterflow port of the common counterflow cooling roots blower generally enters the casing horizontally near the exhaust port on both sides of the casing or enters the casing in the opposite direction of the gas inlet direction of the roots blower, and some horizontal roots blowers also enter the casing from the inner wall of the exhaust end in the opposite direction of the gas inlet direction of the roots blower. This mainly plays the effect of increasing the pressure of the element volume chamber, and entering the casing in the opposite direction of the gas inlet direction of the roots blower is not conducive to the rotation of the rotor and is easy to cause rotor vibration. The patent CN 118008797 A provides a low-noise energy-saving roots pump, the center axis of the counterflow channel on both sides of the pump casing passes through the outermost point of the center of the casing, the center lines of the counterflow channels are tangent to the base circle of the rotor, and the center lines of the counterflow channels are tangent to the base circle of the rotor. The counterflow gas flow can be used to impact the rotor and provide additional torque to the rotor to reduce energy consumption, but the high-pressure counterflow gas enters from the center of the pump casing, and the path to the exhaust port is long, so that more medium is in the internal circulation loop. The medium entering from the counterflow port stays in the pump body for a long time, the leakage flow through the gap between the casing and the rotor is large, the effective flow is reduced more than the roots pump without counterflow port, the counterflow gas flow direction is tangent to the base circle of the rotor, which is easy to form vortex in the exhaust port, and affects the performance parameters of the roots pump. The utility model discloses a counterflow port pointing to the exhaust port is arranged on both sides of the roots blower near the exhaust port, and the high-pressure counterflow gas directly counterattacks the backflow impact when the exhaust port is opened, effectively reduces the backflow impact of the exhaust gas flow, reduces the rotor power, the exhaust temperature and the gas pulsation, and can greatly reduce the medium flow participating in the internal circulation. Compared with the structure of the conventional counterflow port structure of the roots blower, the flow loss is less, energy saving, noise reduction and vibration reduction are realized, and the engineering application value is strong. Utility model content

[0003] The utility model discloses a main purpose is on the basis of keeping traditional counterflow cooling roots blower's advantage, provide a kind of counterflow cooling roots blower that both can reduce power consumption and make flow loss less, to solve the problem proposed in background art.

[0004] To achieve the above object, the utility model provides following technical scheme: a kind of positive pressure or negative pressure roots blower structure of two sides counterflow port pointing exhaust port, including shell, two mutually meshing rotors being arranged in the shell interior, two groups of counterflow ports being distributed in the horizontal plane formed by the center axis of two rotors and between exhaust port and exhaust port and pointing exhaust port, counterflow chamber;The exhaust section of the counterflow cooling positive pressure roots blower is distributed with heat exchanger, exhaust gas is cooled by heat exchanger, and after reducing certain pressure loss, it is backflowed to exhaust port in the direction of pointing exhaust port from the counterflow port;There is no heat exchanger on the exhaust pipeline of the counterflow cooling negative pressure roots blower, introduce normal temperature and normal pressure air as counterflow gas, and counterflow gas is backflowed to exhaust port in the direction of pointing exhaust port.

[0005] The counterflow port is inclined into the shell from the two sides of the shell, and the upper and lower edges or the inside of the counterflow port point to the edges or the inside of the exhaust port, so that the high-pressure counterflow gas directly collides with the exhaust backflow, the vortex intensity caused by the exhaust backflow can be reduced, the shaft power, the exhaust temperature and the exhaust flow pulsation can be reduced, and the internal circulation flow caused by the counterflow is less due to the close distance between the counterflow port and the exhaust port, the leakage amount of the gas flowing into the shell through the gap between the rotor and the shell is also less, and the actual flow is less reduced than the conventional counterflow cooling roots blower.

[0006] The rotor can be a two-blade rotor, a three-blade rotor or a four-blade rotor, the rotor can be a straight-blade rotor or a twisted-blade rotor, and the blade peaks and valleys of the rotor are mutually meshed.

[0007] The counterflow port can be quadrilateral, circular, elliptical or other polygonal, the two side connecting portions of the quadrilateral or other polygonal are rounded, the quadrilateral counterflow ports are arranged on the two sides of the shell along the length direction of the shell, the number of the single-side counterflow ports is n, and 1≤n≤100 is satisfied, the length of a single quadrilateral counterflow port is length, the width of a single quadrilateral counterflow port is width, and 0.01≤length / width≤100 is satisfied, the total area of all the quadrilateral counterflow ports satisfies the required counterflow cooling gas amount, the total area of the polygonal counterflow ports satisfies the required counterflow cooling gas amount, the number of the circular or elliptical counterflow ports on a single side of the shell is m, and 1≤m≤100 is satisfied, and the total area of the circular or elliptical counterflow ports satisfies the required counterflow cooling gas amount.

[0008] The counterflow ports are distributed in the counterflow chamber, the counterflow chamber is connected with the shell, and the counterflow chamber of the positive pressure roots blower is connected with the heat exchanger cooling gas pipeline.

[0009] The single-side reverse flow port of the casing is a single reverse flow pipe with the same flow passage cross-sectional area, or multiple reverse flow pipes with the same total flow passage cross-sectional area, the single reverse flow pipe is located at the middle position of the length direction of the two sides of the casing, the multiple reverse flow pipes are distributed at the positions of the two sides of the casing, the single or multiple reverse flow pipes are distributed between the horizontal plane formed by the central axes of the two rotors and the exhaust port in the height direction, and the upper and lower edges or the inside of the reverse flow pipe is directed to the edge or the inside of the exhaust port.

[0010] The casing of the Roots blower is a vertical structure or a horizontal structure.

[0011] The lower edge of the reverse flow port close to the side of the exhaust port is directed to the edge of the exhaust port (109) on the same side, and high-pressure reverse flow gas can directly collide with the strongest exhaust backflow at the starting moment when the exhaust port is opened, so that the exhaust flow pulsation is reduced, and stable airflow is obtained.

[0012] Beneficial effects

[0013] (1) The reverse flow cooling positive pressure or negative pressure Roots blower can reduce the shaft power of the Roots blower by about 8.5% at most under the premise that the flow rate of the original Roots blower without reverse flow and with the same size is reduced less, and the shaft power is reduced by 5.0% compared with a conventional horizontal reverse flow pipe type Roots blower, the high-pressure reverse flow gas directly collides with the exhaust backflow, the rotor rotation resistance is reduced, and the blower shaft power is reduced.

[0014] (2) The reverse flow cooling positive pressure or negative pressure Roots blower can greatly reduce the higher airflow pulsation, larger noise and vibration problems caused by backflow impact, because the reverse flow gas directly collides with the exhaust backflow.

[0015] (3) The reverse flow cooling positive pressure or negative pressure Roots blower has less difference compared with a conventional reverse flow cooling structure, the flow rate and pressure range are basically the same, the existing structure can be directly energy-savingly transformed by transforming the angle of the reverse flow port or replacing the casing, and has great engineering application value. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a positive pressure vertical reverse flow cooling Roots blower system diagram;

[0017] Figure 2 is a negative pressure vertical reverse flow cooling Roots blower system diagram;

[0018] Figure 3 is a positive pressure horizontal reverse flow cooling Roots blower system diagram;

[0019] Figure 4 is a negative pressure horizontal reverse flow cooling Roots blower system diagram;

[0020] Figure 5Schematic diagram of single-sided counter-flow port shape of quadrilateral (large aspect ratio);

[0021] Figure 6 Schematic diagram of single-sided counter-flow port shape of quadrilateral (small aspect ratio);

[0022] Figure 7 Schematic diagram of single-sided counter-flow port shape of quadrilateral (small aspect ratio);

[0023] Figure 8 Schematic diagram of front view of counter-flow pipe type Roots blower pointing to exhaust port;

[0024] Figure 9 Schematic diagram of side view of counter-flow pipe type Roots blower pointing to exhaust port;

[0025] Figure 10 Schematic diagram of horizontal counter-flow pipe type Roots blower housing;

[0026] Figure 11 Schematic diagram of counter-flow pipe type Roots blower housing pointing to exhaust port;

[0027] Figure 12 Schematic diagram of counter-flow pipe type Roots blower housing pointing to exhaust port;

[0028] Figure 13 Schematic diagram of counter-flow pipe type Roots blower housing pointing to exhaust port;

[0029] Figure 14 Schematic diagram of counter-flow pipe type Roots blower housing pointing to exhaust port;

[0030] Figure 15 Schematic diagram of counter-flow pipe type Roots blower housing pointing to exhaust port;

[0031] Figure 16 Schematic diagram of counter-flow pipe type Roots blower housing pointing to exhaust port;

[0032] Figure 17 Schematic diagram of counter-flow pipe type Roots blower housing pointing to exhaust port;

[0033] Figure 18Figure for relative position of 3-blade Roots blower rotor and counter-flow port when the former intersects with the latter for the counter-flow port of quadrilateral (large length-width ratio) pointing to exhaust port,

[0034] Figure 19 Figure for relative position of 3-blade Roots blower rotor and counter-flow port when the former intersects with the latter for the counter-flow port of quadrilateral (large length-width ratio) pointing to exhaust port,

[0035] In the figure: 100, counter-flow cooling Roots blower structure; 101, casing; 102, rotor; 103, counter-flow port (large length-width ratio quadrilateral); 104, counter-flow chamber; 105, heat exchanger; 106, circular counter-flow port; 107, counter-flow port (small length-width ratio quadrilateral); 108, counter-flow pipe; 109, exhaust port; length, length of single-segment quadrilateral counter-flow port; width, width of single-segment quadrilateral counter-flow port; D, diameter of counter-flow pipe. DETAILED DESCRIPTION

[0036] The specific implementation of the present application will be further described in detail below in combination with the drawings and examples. The following is used to explain the present application, but is not used to limit the scope of the present application.

[0037] Example 1:

[0038] Reference Figure 1 and Figure 5 As shown in the figure, two involute rotors are distributed on the center of the vertical casing of the positive pressure Roots blower, exhaust gas enters the counter-flow chamber and the quadrilateral counter-flow port after being cooled by the heat exchanger, three quadrilateral counter-flow ports are distributed on each side of the casing along the length direction, and a gap is left between the counter-flow ports on the same side to increase the strength of the casing at the position of the counter-flow port, the longest counter-flow port length is set on the premise of ensuring the strength of the casing, the width of the quadrilateral counter-flow port is set according to the required counter-flow cooling gas volume, and the lower edge contour line of the quadrilateral counter-flow port close to the exhaust port side intersects with the side edge line of the same side exhaust port, so that the counter-flow gas in the quadrilateral counter-flow port can directly impact the backflow impact of the exhaust gas flow when the exhaust port is opened, greatly reducing the exhaust gas flow pulsation and improving the performance of the Roots blower.

[0039] Example 2:

[0040] This example is basically the same as example 1, and the difference is as shown in the figure Figure 2 This example is a counter-flow negative pressure Roots blower for conveying air, there is no heat exchanger on the exhaust pipeline, the quadrilateral counter-flow port introduces external normal temperature and pressure atmosphere, and collides with the exhaust backflow in the direction pointing to the edge of the same side exhaust port, thereby reducing the rotor power, reducing the exhaust pulsation, noise and vibration.

[0041] Example 3:

[0042] This example is basically the same as example 1 and example 2, respectively, and the difference is as shown in the figureFigure 3 , 4 As shown, in this embodiment, the Roots blower casing is a horizontal structure, the rotor is a three-lobe rotor, the Roots blower intake direction is perpendicular to the exhaust direction, the counterflow chamber near the exhaust port is connected to the exhaust port, and the counterflow port near the lower edge of the exhaust port points to the same side exhaust port edge.

[0043] Example 4:

[0044] This embodiment is basically the same as Embodiment 1, except that, as follows: Figure 6 As shown, in this embodiment, the shape of the backflow port is circular, and a row of circular backflow ports is distributed along the length of the casing in the backflow chambers on both sides of the casing. The lower edge of the circular backflow port near the exhaust port points to the edge of the exhaust port on the same side.

[0045] Example 5:

[0046] This embodiment is basically the same as Embodiment 1, except that, as follows: Figure 7 As shown, in this embodiment, a row of quadrilateral counterflow ports with a small aspect ratio are distributed in the counterflow chambers on both sides of the housing along the length of the housing. The lower edge of the counterflow port near the exhaust port points to the edge of the exhaust port on the same side.

[0047] Example 6:

[0048] This embodiment is basically the same as Embodiment 1, except that, as follows: Figure 8 , 9 As shown, in this embodiment, the counterflow port is a counterflow pipe, which is located at the center of the casing length. The height direction is distributed between the horizontal plane formed by the center line of the two rotors and the exhaust port. The lower edge of the counterflow pipe near the exhaust port points to the edge of the exhaust port on the same side.

[0049] Based on flow field simulation, the shaft power, actual flow rate, and exhaust temperature of two-lobe Roots blowers with the same structural dimensions, equal counterflow inlet area, and identical inlet and outlet conditions were compared: non-counterflow type, horizontal counterflow pipe type on both sides of the exhaust port, counterflow pipe type pointing towards the exhaust port (the center of the counterflow pipe enters the casing at the same position as the horizontal counterflow pipe type), type with counterflow pipes tangent to the rotor base circle at the center of the casing on both sides, and large aspect ratio quadrilateral counterflow inlet type pointing towards the exhaust port (the center of the counterflow inlet enters the casing at the same position as the horizontal counterflow pipe type). Different casing structures were also compared. Figures 10-13 As shown, the fan performance is as follows Figure 14 and 15As shown, the energy saving rate of the 2-blade Roots blower with the large aspect ratio quadrilateral counter-flow port pointing to the exhaust port is 6.7% higher than that without the counter-flow port, the energy saving rate of the 2-blade Roots blower with the counter-flow pipe tangent to the base circle of the rotor is only 1.5%, and the energy saving rate of the 2-blade Roots blower with the counter-flow pipe pointing to the exhaust port is 2.3%. This is mainly because the high-pressure counter-flow gas of the large aspect ratio quadrilateral counter-flow port pointing to the exhaust port can directly collide with the backflow of the exhaust port when it is opened, thereby reducing the rotor rotation resistance and the gas temperature rise caused by the backflow of the exhaust port. The flow loss rate of the 2-blade Roots blower with the large aspect ratio quadrilateral counter-flow port pointing to the exhaust port, the counter-flow pipe on both sides of the exhaust port, and the counter-flow pipe pointing to the exhaust port is basically between 11.1%-13.9% higher than that without the counter-flow port, while the flow loss rate of the 2-blade counter-flow cooling Roots blower with the counter-flow pipe tangent to the base circle of the rotor is as high as 50.5%. This is related to the large base element volume of the 2-blade Roots blower and the large leakage amount of the counter-flow pipe passing through the gap between the casing and the rotor. Figure 17 The comparison of the single-side counter-flow port flow of the 2-blade Roots blowers with the large aspect ratio quadrilateral counter-flow port pointing to the exhaust port, the counter-flow pipe pointing to the exhaust port, and the counter-flow pipe tangent to the base circle of the rotor shows that the flow of the counter-flow pipe passing through the casing and the rotor is larger, i.e., the flow participating in the internal circulation is larger, so the actual flow of the 2-blade Roots blower with the counter-flow pipe passing through the casing and the rotor is smaller. The single-side counter-flow pipe flow of the 2-blade Roots blower with the large aspect ratio quadrilateral counter-flow port pointing to the exhaust port is the smallest, i.e., the flow participating in the internal circulation is the least. This is related to the fact that the large aspect ratio quadrilateral counter-flow port is close to the exhaust port, and the leakage amount of the gas flowing into the casing through the gap between the rotor and the casing is smaller. It is also related to the fact that the sealing area formed when the rotor blade tip contacts the large aspect ratio quadrilateral counter-flow port is larger.

[0050] Figure 16The shaft power, actual flow rate and exhaust temperature of 3-blade counter-flow cooling Roots blowers of the same structure size, equal counter-flow port area, same inlet and outlet conditions, no counter-flow type, exhaust port two sides horizontal counter-flow pipe type, pointing to the exhaust port counter-flow pipe type (the center of the counter-flow port entering the shell position is the same as the horizontal counter-flow pipe type), through the shell two sides center counter-flow pipe and the rotor base circle tangent type, and the large aspect ratio quadrilateral counter-flow port type (the center of the counter-flow port entering the shell position is the same as the horizontal counter-flow pipe type) are compared, it can be seen that the energy saving rate of the 3-blade Roots blower of the large aspect ratio quadrilateral counter-flow port type pointing to the exhaust port is 8.5% higher than that of the no counter-flow type, the energy saving rate of the 3-blade Roots blower of the through the shell two sides center counter-flow pipe and the rotor base circle tangent type is 6.5%, the energy saving rate of the 3-blade Roots blower of the counter-flow pipe type pointing to the exhaust port is 3.8%, the flow rate loss rate of the 3-blade Roots blower of the exhaust port two sides horizontal counter-flow pipe type, the counter-flow pipe type pointing to the exhaust port and the large aspect ratio quadrilateral counter-flow port type is basically between 3.3%-3.8% compared with the no counter-flow type 3-blade Roots blower, and the flow rate loss rate of the 3-blade counter-flow cooling Roots blower of the through the shell two sides center counter-flow pipe and the rotor base circle tangent type is also reduced due to the reduction of the base element volume, but the flow rate loss is still close to 10%. Figure 18 and 19 As shown in the relative position diagram of the rotor and the counter-flow port of the large aspect ratio quadrilateral counter-flow port type and the through the shell two sides center counter-flow pipe and the rotor base circle tangent type 3-blade Roots blower, the contact area of the rotor and the counter-flow port of the large aspect ratio quadrilateral counter-flow port type is larger when they intersect, the sealing area is larger in the contact time, the leakage is less, and under the premise that the counter-flow port meets the maximum exhaust backflow, reducing the width of the quadrilateral counter-flow port is beneficial to reducing the leakage flow.

[0051] The above examples only express the implementation of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the application, and it should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which belong to the protection scope of the present application.

Claims

1. A positive or negative pressure Roots blower structure with two sides counter-flow port pointing to exhaust port, comprising a counter-flow cooling Roots blower (100), characterized in that, The counterflow cooling Roots blower comprises a casing (101), two mutually meshed rotors (102) arranged inside the casing (101), two groups of counterflow ports (103) distributed on both sides of the exhaust port (109) and located between the horizontal plane formed by the central axes of the two rotors and the exhaust port and pointing to the exhaust port (109), and a counterflow chamber (104).

2. A positive or negative pressure Roots blower structure with two sides counter-flow and finger-pointing exhaust ports according to claim 1, characterized in that The counterflow ports (103) are inclined to enter the casing (101) from both sides of the casing (101), and the upper and lower edges or the inside of the counterflow ports (103) point to the edges or the inside of the exhaust port (109).

3. A positive or negative pressure Roots blower structure with two sides counter-flow and finger-pointing exhaust ports according to claim 1, characterized in that The rotors (102) are two-blade rotors, three-blade rotors or four-blade rotors, and the rotors (102) are straight-blade rotors or twisted-blade rotors, and the blade peaks and blade valleys of the rotors (102) are mutually meshed.

4. A positive or negative pressure Roots blower structure with two sides counter-flow and finger-pointing exhaust ports according to claim 1, characterized in that The counterflow ports (103) are in the shape of quadrilaterals, circles, ellipses or other polygons, the two edges of the quadrilaterals or other polygons are connected with rounded corners, the quadrilateral counterflow ports are arranged on both sides of the casing (101) along the length direction of the casing, the number of the single-sided counterflow ports is n, and 1≤n≤100 is satisfied, the length of a single quadrilateral counterflow port is length, the width of a single quadrilateral counterflow port is width, and 0.01≤length / width≤100 is satisfied, and the total area of all the quadrilateral counterflow ports satisfies the required counterflow cooling air volume, the total area of the polygonal counterflow ports satisfies the required counterflow cooling air volume, the number of the circular or elliptical counterflow ports on a single side of the casing is m, and 1≤m≤100 is satisfied, and the total area of the circular or elliptical counterflow ports satisfies the required counterflow cooling air volume; one row or multiple rows or scattered distribution of the single-sided counterflow ports (103) are arranged in the counterflow chamber (104) in parallel to the length direction of the casing.

5. A positive or negative pressure Roots blower structure with two sides counter-flow and finger-pointing exhaust ports according to claim 1, characterized in that The counterflow ports (103) are distributed in the counterflow chamber (104), the counterflow chamber (104) is connected with the casing (101), and the counterflow chamber (104) of the positive pressure Roots blower is connected in communication with the cooling gas pipeline of the heat exchanger (105).

6. A positive or negative pressure Roots blower structure with two sides counter-flow and finger-pointing exhaust ports according to claim 1, characterized in that The single-sided counterflow port of the casing is in the shape of a single counterflow pipe (108) with the same flow passage cross-sectional area or multiple counterflow pipes with equal total flow passage cross-sectional areas, the single counterflow pipe (108) is located at the middle position of the length direction of both sides of the casing (101), the multiple counterflow pipes are distributed at the positions of both sides of the casing, and the single or multiple counterflow pipes are distributed in the height direction between the horizontal plane formed by the central axes of the two rotors and the exhaust port (109), and the upper and lower edges or the inside of the counterflow pipes point to the edges or the inside of the exhaust port (109).

7. A positive or negative pressure Roots blower structure with two sides counter-flow and finger-pointing exhaust ports according to claim 1, characterized in that The casing (101) of the Roots blower is in a vertical structure or a horizontal structure.

8. A positive or negative pressure Roots blower structure with two sides counter-flow and finger-pointing exhaust ports according to claim 1, characterized in that The counterflow port (103) is directed toward the edge of the same side exhaust port (109) near the lower edge of the exhaust port side.

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