Roots blower with energy recovery device

Abstract

The utility model discloses a Roots blower with an energy recovery device, which comprises a Roots blower unit and an energy recovery unit, and an exhaust pipe of the Roots blower unit is connected with an air return branch pipe; the energy recovery unit comprises two rotors, and the rotating directions of the two rotors are consistent with the rotating direction of a fan rotor of the Roots fan unit; the air return branch pipe is connected with an air inlet of the energy recovery unit, and an air outlet of the energy recovery unit is communicated with the closed cavity of the Roots blower unit through a pipeline. Part of high-pressure gas output by the Roots blower unit flows through the gas return branch pipe to reach the interior of the energy recovery unit, two rotors of the energy recovery unit are pushed to rotate to do work, obtained power conveys energy to the Roots blower unit through the transmission shaft, and energy consumption can be saved. Meanwhile, the gas after acting flows into the closed cavity of the Roots blower unit, so that the pressure in the closed cavity of the Roots blower unit can be increased, and the exhaust noise is effectively reduced.

Description

Technical Field

[0001] The utility model relates to a Roots blower, in particular to a Roots blower provided with an energy recovery device. Background Art

[0002] Roots blower is a positive displacement blower. The principle is that it is a rotary compressor that compresses and conveys gas by using two blade-shaped rotors to make relative motion in the cylinder. This blower has a simple structure and is easy to manufacture. It is widely used in aquaculture oxygenation, sewage treatment aeration, cement transportation, and is more suitable for gas transportation and pressurization systems in low-pressure situations. It can also be used as a vacuum pump, etc. It has the advantages of forced gas transportation, is durable, and is inexpensive, and is very popular among users.

[0003] But Roots blower has the following obvious defects:

[0004] First, the efficiency is low, and the aerodynamic efficiency is usually below 70%. The main reason is that the Roots blower has no internal compression mechanism. During operation, the volume of the sealed cavity formed between the rotor teeth and the shell does not change, and the internal gas cannot be compressed. When this sealed cavity rotates to the exhaust port, the compressed high-pressure gas 25 in the exhaust pipe will recoil into the closed cavity 24 until the gas pressure in the sealed cavity rises above the pressure in the exhaust pipe. Only then can the gas in the sealed cavity be discharged to the outside. We know that the pressure of the gas in the sealed cavity formed between the screw rotor teeth and the shell is equivalent to the atmospheric pressure before it reaches the exhaust port, and the relative pressure value of the gas in the exhaust pipe is often above tens of kPa. This pressure difference causes a strong exhaust recoil phenomenon, that is, the backwash airflow 26 is recoiled from the exhaust port to the sealed cavity formed between the Roots rotor teeth and the shell, see Figure 2 , and then press it out again. This process causes a huge waste of energy. As the exhaust pressure increases, the efficiency of the Roots blower decreases sharply! The pressure ratio of a single-stage Roots blower is often limited to less than 1.0.

[0005] Second, the noise caused by airflow impact is very loud. The exhaust noise of most Roots blowers is above 100db(A). The main reason is the strong exhaust pulsation impact, especially the high-speed gas backflow during the exhaust process, which causes high sound pressure level gas dynamic noise. Even if a muffler or soundproof cover is used, it is difficult to meet environmental protection requirements.

[0006] Third, the high exhaust temperature limits the use range of the Roots blower.

[0007] Due to the above reasons, the exhaust pressure of Roots blower is greatly limited and cannot be used in many occasions. Utility Model Content

[0008] Aiming at the defects of Roots blower, the utility model adds an energy recovery device on the basis of the original Roots blower, thereby solving the problems of low efficiency and high noise of Roots blower in the prior art.

[0009] A Roots blower with an energy recovery device comprises a Roots blower unit, wherein the Roots blower unit comprises a pair of blower rotors arranged in a Roots blower unit housing, a closed cavity is defined between the blower rotors and the Roots blower unit housing, a Roots blower unit air inlet and a Roots blower unit exhaust pipe are arranged on the Roots blower unit housing, and the Roots blower unit exhaust pipe is characterized in that a return air branch pipe is connected to the Roots blower unit exhaust pipe;

[0010] It also includes an energy recovery unit, the energy recovery unit includes two rotors that can be driven by high-pressure gas and are arranged in a housing of the energy recovery unit, and the two rotors are connected to a pair of fan rotors of the Roots blower unit in a one-to-one correspondence, and the energy recovery unit housing is provided with an energy recovery unit air inlet and an energy recovery unit exhaust port; and the air intake direction of the energy recovery unit air inlet is arranged to facilitate the intake gas to act on the surfaces of the two rotors of the energy recovery unit, and the direction of driving the two rotors to rotate is consistent with the rotation direction of the fan rotor of the Roots blower unit;

[0011] The return air branch pipe is connected to the air inlet of the energy recovery unit, and the exhaust port of the energy recovery unit is connected to the closed cavity of the Roots blower unit through a pipeline.

[0012] In a preferred embodiment of the utility model, the Roots blower unit and the energy recovery unit share a housing, and the two units are separated by an intermediate wall plate. Further, the two rotors of the energy recovery unit correspond one-to-one to a pair of rotors of the Roots blower unit, and the two corresponding rotors share a transmission shaft.

[0013] In a preferred embodiment of the utility model, the two rotors of the energy recovery unit are a pair of Roots blower rotors. Alternatively, the two rotors of the energy recovery unit are a pair of screw male and female rotors, and the impeller size thereof is adapted to the housing of the energy recovery unit.

[0014] In the preferred embodiment of the utility model, the pipeline includes an A-side air intake branch pipe and a B-side air intake branch pipe arranged on the side walls of the Roots blower unit housing. The A-side air intake branch pipe and the B-side air intake branch pipe are each a group of pipes, which are arranged in a line and are respectively connected to the housing. The A-side air intake branch pipe and the B-side air intake branch pipe are in turn connected to the exhaust port of the energy recovery unit. The exhaust port of the energy recovery unit is connected to the closed cavity of the Roots blower unit through the A-side air intake branch pipe and the B-side air intake branch pipe.

[0015] In a preferred embodiment of the utility model, a gas cooler is provided on the return air branch pipe, and the outlet of the gas cooler is connected to the air inlet of the energy recovery unit.

[0016] The beneficial effects of the utility model are:

[0017] 1. A part of the high-pressure gas output by the Roots blower unit flows through the return air branch pipe and the air inlet of the energy recovery unit, reaches the inside of the energy recovery unit, and drives the two rotors of the energy recovery unit to rotate and do work. The power obtained transmits the energy to the Roots blower unit through the transmission shaft. The power required for the operation of the Roots blower unit is obtained by the transmission shaft from the external power device. The power obtained from the energy recovery unit can reduce the load of the external power device after being transmitted to the Roots blower unit, which can save energy consumption. Especially when the exhaust pressure is high, the energy-saving effect is significant.

[0018] 2. At the same time, the gas after work still has a certain pressure, which is output from the exhaust port of the energy recovery unit and flows into the closed cavity of the Roots blower unit through the A-side intake branch pipe and the B-side intake branch pipe. The pressure in the closed cavity of the Roots blower unit can be increased, that is, the gas density therein will be increased. The strong gas dynamic impact in the exhaust process of ordinary Roots blowers can be effectively reduced and avoided, and the exhaust noise can be significantly and effectively controlled.

[0019] 3. In addition, by adding a gas cooler on the return air branch pipe, the exhaust temperature can be reduced. The reduction of exhaust temperature can not only expand and increase the exhaust pressure of the Roots blower, but also play an important role in improving the reliability of the Roots blower and ensuring long-term safe operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The overall structure diagram of a Roots blower embodiment 1 provided with an energy recovery device

[0021] Figure 2 Schematic diagram of the existing Roots blower structure

[0022] Figure 3 Schematic diagram of the independent structures of the Roots blower unit and the energy recovery unit of Example 2

[0023] Figure 4 The two rotors of the energy recovery unit of Example 3 are a pair of screw yin and yang rotors.

[0024] Figure 5 Schematic diagram of a gas cooler provided in Example 4

[0025] Energy recovery unit---1 Roots blower unit---2 Housing--3

[0026] Roots blower rotor A---4 A side air inlet branch---5 Roots blower unit air inlet---6

[0027] Synchronous gear---7 B side intake branch pipe---8 Return branch pipe---9

[0028] Air return port---10 Roots blower exhaust port---11 Roots blower unit exhaust pipe---12

[0029] Roots blower rotor B---13 Middle wall plate---14 Base---15

[0030] B side air supply main pipe---16 Energy recovery unit exhaust port---17 Drive shaft B---18

[0031] Energy recovery rotor B---19 Transmission shaft A---20 Energy recovery rotor A---21

[0032] A-side air supply main pipe--22 Energy recovery unit air inlet---23 Closed cavity---24

[0033] High Pressure Gas --- 25 Backwash Air --- 26 Gas Cooler --- 27

[0034] Energy recovery independent unit---28 Roots blower independent unit---29

[0035] Coupling---30 Screw female rotor---31 Screw male rotor---32 DETAILED DESCRIPTION

[0036] The technical solution of the utility model will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the implementation methods of the present application, not all of the implementation methods; and the structures shown in the accompanying drawings are only schematic and do not represent physical objects. It should be noted that based on these embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0037] It should be noted that the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion in this article, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical or equivalent elements in the process, method, article or device including the elements.

[0038] The terms "upper", "lower", "inner", "outer", etc. do not constitute absolute spatial relationship limitations, but are only concepts of relative positions, which can be understood by those skilled in the art. Example 1

[0039] A Roots blower with an energy recovery device comprises a housing 3, which can be arranged on a platform through a base 15. An intermediate wall plate 14 is arranged inside the housing 3 to divide the interior of the housing into two parts, one side of the intermediate wall plate 14 is a Roots blower unit 2, and the other side is an energy recovery unit 1.

[0040] The Roots blower unit 1 comprises a Roots blower rotor A (4), a Roots blower rotor B (13), a Roots blower unit air inlet 6, a Roots blower unit exhaust pipe 12, and a Roots blower exhaust port 11; the Roots blower rotor is adapted to the housing 3, and a closed cavity 24 is defined between the Roots blower rotor and the Roots blower unit housing. The Roots blower rotor A (4) and the Roots blower rotor B (13) are transmission-connected to an external power device (not shown) via a synchronous gear 7.

[0041] The energy recovery unit 1 comprises an energy recovery rotor A (21), an energy recovery rotor B (19), an energy recovery unit air inlet 23, and an energy recovery unit air outlet 17; the energy recovery rotor A (21) and the energy recovery rotor B (19) are also a pair of Roots blower rotors. The Roots blower rotor A (4) and the energy recovery rotor A (21) share a transmission shaft A (20); the Roots blower rotor B (13) and the energy recovery rotor B (19) share a transmission shaft B (18). The energy recovery unit air outlet 17 is respectively connected to the A-side air supply main pipe 22 and the B-side air supply main pipe 16. The air intake direction of the energy recovery unit air inlet 23 is set to facilitate the intake gas to act on the two rotor surfaces of the energy recovery unit, and to drive the two rotors to rotate in the same direction as the blower rotor of the Roots blower unit. The purpose is: the high-pressure gas output by the Roots blower unit drives the two rotors of the energy recovery unit to rotate and work, and the power obtained is transmitted to the Roots blower unit through the transmission shaft, which can reduce the load of the external power device of the Roots blower unit and save energy. Especially when the exhaust pressure is high, the energy-saving effect is significant.

[0042] The exhaust pipe 12 of the Roots blower unit is provided with a return port 10, and the return port 10 is connected to a return branch pipe 9, and the return branch pipe 9 is connected to the air inlet 23 of the energy recovery unit. The side walls of the shell of the Roots blower unit 2 are respectively provided with an A-side intake branch pipe 5 and a B-side intake branch pipe 8. The A-side intake branch pipe 5 and the B-side intake branch pipe 8 are a group of pipes, which are arranged in a line. One end of them points to the shell and penetrates (communicates) with the shell and is flush with the inner wall of the shell. The other ends of the A-side intake branch pipe 5 and the B-side intake branch pipe 8 are respectively connected to the A-side air supply main pipe 22 and the B-side air supply main pipe 16.

[0043] A portion of the high-pressure gas 25 output by the Roots blower flows through the return air branch pipe 9 and the air inlet 23 of the energy recovery unit to reach the interior of the energy recovery unit, thereby driving the energy recovery rotor A (21) and the energy recovery rotor B (19) to rotate and perform work. The power obtained is transmitted to the Roots blower unit 2 via the transmission shaft A (20) and the transmission shaft B (18), thereby reducing the load of the external power device of the Roots blower unit and saving energy consumption.

[0044] The gas after work still has a certain pressure, and is output at the exhaust port of the energy recovery unit, passes through the A-side gas supply main pipe 22 and the B-side gas supply main pipe 16, and flows into the closed cavity 24 of the Roots blower unit from the A-side intake branch pipe 5 and the B-side intake branch pipe 8. The pressure in the closed cavity of the Roots blower unit can be increased, that is, the gas density therein can be increased. The strong gas dynamic impact in the exhaust process of the ordinary Roots blower is effectively reduced and avoided, and the backwash noise at the exhaust port of the Roots blower is reduced. Example 2

[0045] See also Figure 3 The difference from the first embodiment is that the independent Roots blower unit 29 and the independent energy recovery unit 28 are independent devices, which are fixedly installed by the base. The two rotors of the energy recovery unit are connected to the pair of blower rotors of the Roots blower unit by the coupling 30 in a one-to-one correspondence. Example 3

[0046] See also Figure 4 , which is different from Example 1 in that the two rotors of the energy recovery unit are a pair of screw male and female rotors (31, 32), whose sizes are adapted to the housing. The energy recovery unit and the Roots blower unit share a housing, and the two units are separated by an intermediate wall plate 14. The Roots blower rotor A (4) and the screw female rotor (31) share a transmission shaft; the Roots blower rotor B (13) and the screw male rotor (32) share a transmission shaft.

[0047] The air intake direction of the air intake port of the energy recovery unit is arranged so that the intake gas drives the rotation direction of the screw male and female rotors to be consistent with the rotation direction of the blower rotor of the Roots blower unit. Example 4

[0048] See also Figure 5 The difference from Example 1 is that a gas cooler 27 is provided in the connecting pipeline of the exhaust port of the energy recovery unit, and the outlet of the gas cooler is connected to the A-side gas supply main pipe (22) and the B-side gas supply main pipe (16).

[0049] After the high-temperature gas discharged from the energy recovery unit is cooled, it passes through the A-side air supply main pipe 22 and the B-side air supply main pipe 16, and flows into the closed cavity of the Roots blower unit from the A-side air intake branch pipe 5 and the B-side air intake branch pipe 8. After the low-temperature gas enters the closed cavity of the Roots blower unit, the gas temperature in the closed cavity of the Roots blower unit will inevitably drop, resulting in a decrease in the exhaust temperature of the Roots blower unit. The reduction in exhaust temperature can not only expand and increase the exhaust pressure of the Roots blower, but also plays an important role in improving the reliability of the Roots blower and ensuring long-term safe operation.

[0050] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and the specification only describe the principles of the utility model. The utility model may be subject to various changes and improvements without departing from the spirit and scope of the utility model. These changes and improvements fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A Roots blower with an energy recovery device, comprising a Roots blower unit, wherein the Roots blower unit comprises a pair of blower rotors arranged in a Roots blower unit housing, wherein a closed cavity is defined between the blower rotors and the Roots blower unit housing, and a Roots blower unit air inlet and a Roots blower unit exhaust pipe are arranged on the Roots blower unit housing, wherein: The exhaust pipe of the Roots blower unit is connected with a return air branch pipe; It also includes an energy recovery unit, the energy recovery unit includes two rotors that can be driven by high-pressure gas and are arranged in a housing of the energy recovery unit, and the two rotors are connected to a pair of fan rotors of the Roots blower unit in a one-to-one correspondence, and the energy recovery unit housing is provided with an energy recovery unit air inlet and an energy recovery unit exhaust port; and the air intake direction of the energy recovery unit air inlet is arranged to facilitate the intake gas to act on the surfaces of the two rotors of the energy recovery unit, and the direction of driving the two rotors to rotate is consistent with the rotation direction of the fan rotor of the Roots blower unit; The return air branch pipe is connected to the air inlet of the energy recovery unit, and the exhaust port of the energy recovery unit is connected to the closed cavity of the Roots blower unit through a pipeline.

2. The Roots blower with an energy recovery device according to claim 1, characterized in that: The Roots blower unit and the energy recovery unit share a shell, and the two units are separated by an intermediate wall plate.

3. The Roots blower with an energy recovery device according to claim 2, characterized in that: The two rotors of the energy recovery unit correspond one to one with a pair of rotors of the Roots blower unit, and the two corresponding rotors share a transmission shaft.

4. The Roots blower with an energy recovery device according to claim 1, characterized in that: The two rotors of the energy recovery unit are a pair of Roots blower rotors.

5. The Roots blower with an energy recovery device according to claim 1, characterized in that: The two rotors of the energy recovery unit are a pair of screw male and female rotors.

6. The Roots blower with an energy recovery device according to claim 1, characterized in that: The pipeline includes an A-side air intake branch pipe and a B-side air intake branch pipe arranged on the side walls of the Roots blower unit housing. The A-side air intake branch pipe and the B-side air intake branch pipe are each a group of pipes, which are arranged in a line and are respectively connected to the Roots blower unit housing. The A-side air intake branch pipe and the B-side air intake branch pipe are in turn connected to the exhaust port of the energy recovery unit. The exhaust port of the energy recovery unit is connected to the closed cavity of the Roots blower unit through the A-side air intake branch pipe and the B-side air intake branch pipe.

7. The Roots blower with an energy recovery device according to claim 1, characterized in that: A gas cooler is provided on the return air branch pipe, and an outlet of the gas cooler is communicated with an air inlet of the energy recovery unit.

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