阅读说明：本技术 一种中高压螺杆压缩机及排气量和气容比的控制方法 (Medium-high pressure screw compressor and control method of air displacement and air-to-volume ratio ) 是由 不公告发明人 于 2021-08-10 设计创作，主要内容包括：本发明公开了一种中高压螺杆压缩机及排气量和气容比的控制方法,其中,中高压螺杆压缩机中,第一腔室设有能够变速驱动第一级螺杆转子的低压级驱动电机,第二腔室能够变速驱动第二级螺杆转子的高压级驱动电机,检测装置能够检测压缩气体的压力和/或温度,控制单元根据检测信号调节低压级驱动电机以及高压级驱动电机的转速,以调节排气端的排气量；第一腔室和/或第二腔室还设有调节阀,调节阀包括阀体和转轴,转轴与阀体相连,旋转转轴能够使阀体沿螺杆转子的轴线方向往复移动,并使阀体在移动过程中改变所述中高压螺杆压缩机的排气量。本发明所公开的中高压螺杆压缩机具有方便调节排气量和气容比、结构简单、应用范围广泛等优点。(The invention discloses a medium-high pressure screw compressor and a control method of air displacement and air-volume ratio, wherein in the medium-high pressure screw compressor, a first chamber is provided with a low-pressure stage driving motor capable of driving a first stage screw rotor in a variable speed manner, a second chamber is capable of driving a high-pressure stage driving motor of a second stage screw rotor in a variable speed manner, a detection device is capable of detecting the pressure and/or temperature of compressed air, and a control unit adjusts the rotating speed of the low-pressure stage driving motor and the high-pressure stage driving motor according to a detection signal so as to adjust the air displacement of an air exhaust end; the first chamber and/or the second chamber are/is also provided with a regulating valve, the regulating valve comprises a valve body and a rotating shaft, the rotating shaft is connected with the valve body, the rotating shaft can enable the valve body to move in a reciprocating mode along the axis direction of the screw rotor, and the valve body can change the displacement of the medium-high pressure screw compressor in the moving process. The medium-high pressure screw compressor disclosed by the invention has the advantages of convenience in regulating the air displacement and the air-volume ratio, simple structure, wide application range and the like.)

1. A middle-high pressure screw compressor is characterized by comprising a shell, a control unit and a compression chamber arranged in the shell, wherein the compression chamber comprises a first chamber and a second chamber, a first-stage screw rotor is arranged in the first chamber, a second-stage screw rotor is arranged in the second chamber, the compression chamber is provided with an air inlet end arranged in the first chamber and an air outlet end arranged in the second chamber, an air outlet of the first chamber is communicated with an air inlet of the second chamber, so that air enters the compression chamber from the air inlet end and is discharged from the air outlet end after being compressed twice by the first-stage screw rotor and the second-stage screw rotor;

the first chamber is provided with a low-pressure stage driving motor, the low-pressure stage driving motor can drive the first stage screw rotor in a variable speed manner, the second chamber is provided with a high-pressure stage driving motor, the high-pressure stage driving motor can drive the second stage screw rotor in a variable speed manner, the medium-high pressure screw compressor further comprises a detection device arranged in the compression chamber, the detection device can detect the pressure and/or the temperature of compressed gas, and the control unit can receive signals detected by the detection device and adjust the rotating speed of the low-pressure stage driving motor and the rotating speed of the high-pressure stage driving motor so as to adjust the exhaust amount of the exhaust end;

the first cavity and/or the second cavity still is equipped with the governing valve, the governing valve includes valve body and pivot, the pivot with the valve body links to each other, and is rotatory the pivot can make the valve body is followed screw rotor's axis direction reciprocating motion, and make the valve body changes at the removal in-process the displacement of middle and high pressure screw compressor.

2. Medium-high pressure screw compressor according to claim 1,

the first chamber is provided with the regulating valve;

the exhaust volume of the first chamber adopts a formulaChanging the rotating speed of the low-pressure-level driving motor and/or changing the regulating coefficient of the regulating valve to regulate the air displacement of the medium-high pressure screw compressor, wherein C is the air displacement, X is the regulating coefficient of the regulating valve, n is the rotating speed of the low-pressure-level driving motor, T is the rated torque of the low-pressure-level driving motor, eta is the efficiency, Q_SIs the initial air inflow of the air inlet end, t is the running time of the low-voltage level driving motor, m is the initial air inlet mass, omega_sFor the isentropic compression process specific work, n_tThe number of revolutions of the low pressure stage drive motor required for each cycle of the first stage screw rotor.

3. Medium-high pressure screw compressor according to claim 1,

the control unit comprises a frequency converter, and the running rotating speed and power parameters of the low-voltage-level driving motor and the high-voltage-level driving motor are controlled through the frequency converter.

4. Medium-high pressure screw compressor according to claim 1,

the detection device is set as a multi-parameter detection integrated composite sensor, the multi-parameter detection integrated composite sensor is arranged at the air inlet end, the air outlet, the air inlet and/or the air outlet end, and the multi-parameter detection integrated composite sensor can at least detect pressure and temperature signals.

5. Medium-high pressure screw compressor according to claim 1,

one end of the rotating shaft is connected with the valve body, and the other end of the rotating shaft extends to the outside of the shell and is provided with a handle used for rotating the rotating shaft to move the adjusting valve.

6. Medium-high pressure screw compressor according to claim 1,

the first chamber is provided with the regulating valve;

the valve body comprises an exhaust volume adjusting valve part arranged close to the air inlet end and an air volume ratio adjusting valve part arranged close to the air outlet, the exhaust volume adjusting valve part is in threaded connection with the rotating shaft, the exhaust volume adjusting valve part has a first position abutting against the air volume ratio adjusting valve part and a second position separated from the first position, the rotating shaft is rotated to separate the exhaust volume adjusting valve part from the air volume ratio adjusting valve part so as to form an exhaust channel between the exhaust volume adjusting valve part and the air volume ratio adjusting valve part, and gas in the first chamber can be exhausted through the exhaust channel;

the gas-to-liquid ratio adjusting valve part is sleeved on the rotating shaft and can slide on the rotating shaft, so that the adjusting valve can adjust the gas-to-liquid ratio of the medium-high pressure screw compressor.

7. Medium-high pressure screw compressor according to claim 6,

the gas capacity is than regulation valve portion has along a plurality of location portions that the axis direction of screw rotor set up, well high pressure screw compressor still including set firmly in the fixing device of first cavity, the gas capacity is in when the regulation valve portion slides in the pivot, fixing device can with a plurality of one cooperation in the location portion, with it is fixed to the gas capacity is than regulation valve portion.

8. Medium-high pressure screw compressor according to claim 6,

the medium-high pressure screw compressor further comprises a circulating pipeline, one end of the circulating pipeline is communicated with the exhaust channel, and the other end of the circulating pipeline is communicated with the air inlet end of the first cavity.

9. A method for controlling the air displacement of a medium-high pressure screw compressor is characterized in that,

the method comprises the following steps:

the method comprises the following steps: setting a plurality of initial pressure values and the rotating speed of a driving motor corresponding to the initial pressure values in a compression chamber in a medium-high pressure screw compressor;

step two: detecting the exhaust pressure of the compression chamber at the exhaust end through a detection device, and comparing the exhaust pressure with an initial pressure value;

step three: when the exhaust pressure is equal to the initial pressure value, the gas is conveyed and the driving motor is operated at the maximum speed under the condition that the exhaust volume adjusting valve part is abutted with the gas-to-volume ratio adjusting valve part, namely the exhaust channel is closed;

step four: the rotation speed of the driving motor is adjusted through the frequency converter to change the air displacement, so that the expected air displacement is realized.

10. A control method for the air displacement and the air-to-volume ratio of a medium-high pressure screw compressor is characterized in that,

the method comprises the following steps:

the method comprises the following steps: rotating the rotating shaft to make the gas-to-volume ratio regulating valve part slide on the rotating shaft to change the gas-to-volume ratio in the compression chamber, and fixing the gas-to-volume ratio regulating valve part which slides in place through the cooperation of the fixing device and the positioning part to make the gas-to-volume ratio in the compression chamber constant;

step two: rotating the rotating shaft to move the air displacement regulating valve part in the axial direction of the screw rotor, separating the air displacement regulating valve part from the air volume ratio regulating valve part, opening the air exhaust channel, and exhausting a part of compressed air entering the compression chamber through the air exhaust channel;

step three: the gas exhausted from the exhaust passage is returned to the air inlet end via the circulating pipeline for recompression.

Technical Field

The invention relates to the technical field of air compressors, in particular to a medium-high pressure screw compressor and a control method of air displacement and air-volume ratio.

Background

The air compressor is a device for compressing gas, and is widely applied to many fields, and particularly, the positive displacement screw compressor has the advantages of high reliability, convenience in operation, stable power, strong practicability and the like. The screw compressor mainly utilizes the mutual meshing of tooth space volumes of screw rotors to cause the change of element volume consisting of tooth space to complete the processes of gas suction, compression and discharge.

The existing screw compressor is mainly a single-stage or two-stage screw compressor, and particularly the two-stage screw compressor can obtain compressed gas with higher air pressure. The conventional single screw compressor mainly adjusts the air displacement through a slide valve, the slide valve can change the effective working length of a screw rotor when moving along the axial direction of the screw rotor in a slide valve cavity so as to change the air displacement, and the slide valve is mainly driven by a hydraulic structure. However, the difficulty coefficient of adjusting the displacement of the two-stage or more screw compressors only by means of the slide valve is high, the working efficiency of the whole screw compressor is reduced, the application of the multi-stage screw compressor in many fields is limited, and the multi-stage screw compressor can only be applied to places with small requirements on displacement change.

Therefore, it is highly desirable to invent a middle and high pressure screw compressor which facilitates the adjustment of the displacement so that the multistage screw compressor can be more widely used.

Disclosure of Invention

The invention provides a medium-high pressure screw compressor, which aims to solve at least one technical problem in the technical problems.

The medium-high pressure screw compressor provided by the invention is realized by the following technical scheme:

a middle-high pressure screw compressor comprises a shell, a control unit and a compression chamber arranged in the shell, wherein the compression chamber comprises a first chamber and a second chamber, a first-stage screw rotor is arranged in the first chamber, a second-stage screw rotor is arranged in the second chamber, the compression chamber is provided with an air inlet end arranged in the first chamber and an air outlet end arranged in the second chamber, an air outlet of the first chamber is communicated with an air inlet of the second chamber, so that air enters the compression chamber from the air inlet end and is discharged from the air outlet end after being compressed twice by the first-stage screw rotor and the second-stage screw rotor; the first chamber is provided with a low-pressure stage driving motor, the low-pressure stage driving motor can drive the first stage screw rotor in a variable speed manner, the second chamber is provided with a high-pressure stage driving motor, the high-pressure stage driving motor can drive the second stage screw rotor in a variable speed manner, the medium-high pressure screw compressor further comprises a detection device arranged in the compression chamber, the detection device can detect the pressure and/or the temperature of compressed gas, and the control unit can receive signals detected by the detection device and adjust the rotating speed of the low-pressure stage driving motor and the rotating speed of the high-pressure stage driving motor so as to adjust the exhaust amount of the exhaust end; the first cavity and/or the second cavity still is equipped with the governing valve, the governing valve includes valve body and pivot, the pivot with the valve body links to each other, and is rotatory the pivot can make the valve body is followed screw rotor's axis direction reciprocating motion, and make the valve body changes at the removal in-process the displacement of middle and high pressure screw compressor.

Further, the first chamber is provided with the regulating valve; the exhaust volume of the first chamber adopts a formulaChanging the rotating speed of the low-pressure-level driving motor and/or changing the regulating coefficient of the regulating valve to regulate the air displacement of the medium-high pressure screw compressor, wherein C is the air displacement, X is the regulating coefficient of the regulating valve, n is the rotating speed of the low-pressure-level driving motor, T is the rated torque of the low-pressure-level driving motor, eta is the efficiency, Q_SIs the initial air inflow of the air inlet end, t is the running time of the low-voltage level driving motor, m is the initial air inlet mass, omega_sFor the isentropic compression process specific work, n_tThe number of revolutions of the low pressure stage drive motor required for each cycle of the first stage screw rotor.

Further, the control unit comprises a frequency converter, and the frequency converter is used for controlling the running rotating speed and power parameters of the low-voltage-level driving motor and the high-voltage-level driving motor.

Furthermore, the detection device is set as a multi-parameter detection integrated composite sensor, the multi-parameter detection integrated composite sensor is arranged at the air inlet end, the air outlet, the air inlet and/or the air outlet end, and the multi-parameter detection integrated composite sensor can at least detect pressure and temperature signals.

Furthermore, one end of the rotating shaft is connected with the valve body, and the other end of the rotating shaft extends to the outside of the shell and is provided with a handle used for rotating the rotating shaft to move the adjusting valve.

Further, the first chamber is provided with the regulating valve; the valve body comprises an exhaust volume adjusting valve part arranged close to the air inlet end and an air volume ratio adjusting valve part arranged close to the air outlet, the exhaust volume adjusting valve part is in threaded connection with the rotating shaft, the exhaust volume adjusting valve part has a first position abutting against the air volume ratio adjusting valve part and a second position separated from the first position, the rotating shaft is rotated to separate the exhaust volume adjusting valve part from the air volume ratio adjusting valve part so as to form an exhaust channel between the exhaust volume adjusting valve part and the air volume ratio adjusting valve part, and gas in the first chamber can be exhausted through the exhaust channel; the gas-to-liquid ratio adjusting valve part is sleeved on the rotating shaft and can slide on the rotating shaft, so that the adjusting valve can adjust the gas-to-liquid ratio of the medium-high pressure screw compressor.

Further, the gas capacity ratio adjusting valve portion has a plurality of positioning portions arranged in the axial direction of the screw rotor, the medium-high pressure screw compressor further comprises a fixing device fixedly arranged in the first chamber, and when the gas capacity ratio adjusting valve portion slides on the rotating shaft, the fixing device can be matched with one of the plurality of positioning portions to fix the gas capacity ratio adjusting valve portion.

Furthermore, the medium-high pressure screw compressor further comprises a circulating pipeline, one end of the circulating pipeline is communicated with the exhaust channel, and the other end of the circulating pipeline is communicated with the air inlet end of the first cavity.

The invention also provides a control method of the air displacement of the medium-high pressure screw compressor, which comprises the following steps: the method comprises the following steps: setting a plurality of initial pressure values and the rotating speed of a driving motor corresponding to the initial pressure values in a compression chamber in a medium-high pressure screw compressor; step two: detecting the exhaust pressure of the compression chamber at the exhaust end through a detection device, and comparing the exhaust pressure with an initial pressure value; step three: when the exhaust pressure is equal to the initial pressure value, the gas is conveyed and the driving motor is operated at the maximum speed under the condition that the exhaust volume adjusting valve part is abutted with the gas-to-volume ratio adjusting valve part, namely the exhaust channel is closed; step four: the rotation speed of the driving motor is adjusted through the frequency converter to change the air displacement, so that the expected air displacement is realized.

The invention also provides a control method of the air displacement and the air-to-volume ratio of the medium-high pressure screw compressor, which comprises the following steps: the method comprises the following steps: rotating the rotating shaft to make the gas-to-volume ratio regulating valve part slide on the rotating shaft to change the gas-to-volume ratio in the compression chamber, and fixing the gas-to-volume ratio regulating valve part which slides in place through the cooperation of the fixing device and the positioning part to make the gas-to-volume ratio in the compression chamber constant; step two: rotating the rotating shaft to move the air displacement regulating valve part in the axial direction of the screw rotor, separating the air displacement regulating valve part from the air volume ratio regulating valve part, opening the air exhaust channel, and exhausting a part of compressed air entering the compression chamber through the air exhaust channel; step three: the gas exhausted from the exhaust passage is returned to the air inlet end via the circulating pipeline for recompression.

Due to the adoption of the technical scheme, the invention has the technical effects that:

1. in the medium-high pressure screw compressor provided by the invention, the first-stage screw rotor is driven by the low-pressure-stage driving motor in a variable speed manner, the second-stage screw rotor is driven by the high-pressure-stage driving motor in a variable speed manner, and the displacement of the medium-high pressure screw compressor is adjusted by moving the adjusting valve in a combined manner, so that the medium-high pressure screw compressor can be suitable for different working environments, and the application field is wider. The rotating speed of the low-pressure-level driving motor and the rotating speed of the high-pressure-level driving motor can be accurately changed to each revolution through the control of the control unit, so that the adjustment of the displacement can be accurately and slightly changed, and the medium-high pressure screw compressor can be applied to a working environment with high requirements on the adjustment precision of the displacement. In addition, the valve body moves in the chamber by rotating the rotating shaft, and compared with the adjusting mode of changing the rotating speed of the driving motor, the adjusting mode enables the degree of change of the exhaust gas volume in the moving process of the adjusting valve to be larger, and belongs to a coarse adjusting mode.

2. In a preferred embodiment of the present invention, the exhaust volume of the first chamber is expressed by a formulaThrough the formula, the air displacement of the medium-high pressure screw compressor can be adjusted only by changing the rotating speed of the low-pressure stage driving motor and/or changing the adjusting coefficient of the adjusting valve, and the combination of the two adjusting modes is more convenient to adjust to the expected air displacement. The cooperation of two kinds of regulation modes is used to make well high-pressure screw compressor switch over at will in the mode of fine setting and coarse adjustment displacement more humanized, for example, can adjust driving motor's rotational speed to a definite value, make initial displacement be in the floating range around required displacement volume, when the displacement needs roughly to change, only need just can realize through removing the governing valve for driving motor can guarantee certain energy-conserving effect.

3. As a preferred embodiment of the present invention, the first chamber is provided with the regulating valve; the valve body comprises an exhaust volume adjusting valve part arranged close to the air inlet end and an air volume ratio adjusting valve part arranged close to the air outlet, the exhaust volume adjusting valve part is in threaded connection with the rotating shaft, the exhaust volume adjusting valve part has a first position abutting against the air volume ratio adjusting valve part and a second position separated from the first position, the rotating shaft is rotated to separate the exhaust volume adjusting valve part from the air volume ratio adjusting valve part so as to form an exhaust channel between the exhaust volume adjusting valve part and the air volume ratio adjusting valve part, and gas in the first chamber can be exhausted through the exhaust channel; the gas-to-liquid ratio adjusting valve part is sleeved on the rotating shaft and can slide on the rotating shaft, so that the adjusting valve can adjust the gas-to-liquid ratio of the medium-high pressure screw compressor. The regulating valve integrates double functions of air displacement regulation and air-to-volume ratio regulation, and compared with a structure that two valves, namely the air displacement regulating valve and the air-to-volume ratio regulating valve, are arranged in the compression chamber at the same time, the structure is simple, the internal space of the compression chamber is saved, and the air displacement and the air-to-volume ratio can be regulated simultaneously by rotating one regulating valve.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a first sectional view showing the inside of a first chamber of a medium-high pressure screw compressor according to the present invention, in which a discharge air volume adjusting valve portion is in contact with a gas capacity ratio adjusting valve portion, that is, a discharge passage is closed;

FIG. 2 is a second sectional view of the interior of the first chamber of the medium-high pressure screw compressor according to the present invention, showing a state in which the discharge amount adjusting valve section is separated from the gas capacity ratio adjusting valve section, i.e., the discharge passage is opened;

fig. 3 is a circuit diagram of a medium-high pressure screw compressor provided by the invention.

Reference numerals:

1 shell, 11 first chamber, 12 first stage screw rotor, 121 air inlet end, 122 air outlet, 13 second stage screw rotor, 131 air inlet, 132 air outlet end, 14 low pressure stage driving motor, 15 high pressure stage driving motor, 16 regulating valve, 161 valve body, 1611 air displacement regulating valve portion, 1612 air-to-air ratio regulating valve portion, 1613 air outlet channel, 1614 positioning portion, 162 rotating shaft, 163 handle, 164 elastic element, 17 circulation pipeline and 18 fixing device.

Detailed Description

In order to more clearly explain the overall concept of the invention, the following detailed description is given by way of example in conjunction with the accompanying drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

In addition, in the description of the present invention, it is to be understood that the terms "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present invention and simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus are not to be construed as limiting the present invention.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The middle-high pressure screw compressor shown in fig. 1 to 3 includes a casing 1, a control unit, and a compression chamber disposed in the casing 1, where the compression chamber includes a first chamber 11 and a second chamber, a first stage screw rotor 12 is disposed in the first chamber 11, a second stage screw rotor 13 is disposed in the second chamber, the compression chamber has an air inlet 121 disposed in the first chamber 11, and an air outlet 132 disposed in the second chamber, and an air outlet 122 of the first chamber 11 is communicated with an air inlet 131 of the second chamber, so that air enters the compression chamber from the air inlet 121, and is compressed twice by the first stage screw rotor 12 and the second stage screw rotor 13, and then is discharged from the air outlet 132. First cavity 11 is equipped with low pressure level driving motor 14, low pressure level driving motor 14 can the variable speed drive first level screw rotor 12, the second cavity is equipped with high pressure level driving motor 15, high pressure level driving motor 15 can the variable speed drive second level screw rotor 13, well high pressure screw compressor is still including locating detection device in the compression cavity, detection device can detect compressed gas's pressure and/or temperature, the control unit can accept the signal that detection device detected and adjust low pressure level driving motor 14 and high pressure level driving motor 15's rotational speed, in order to adjust the displacement of exhaust end 132 department. In specific implementation, the first chamber 11 or the second chamber is further provided with a regulating valve 16, the regulating valve 16 comprises a valve body 161 and a rotating shaft 162, the rotating shaft 162 is connected with the valve body 161, the rotating shaft 162 is rotated to enable the valve body 161 to move in a reciprocating manner along the axis direction of the screw rotor, and the valve body 161 changes the exhaust gas volume of the medium-high pressure screw compressor in the moving process. As an alternative embodiment, both the first chamber 11 and the second chamber are provided with a regulating valve 16.

Fig. 1 to 2 only show the sectional structure of the first chamber, and the internal structure of the second chamber may refer to the sectional structure of the first chamber.

In the medium-high pressure screw compressor provided by the invention, the first-stage screw rotor 12 is driven by the low-pressure-stage driving motor 14 in a variable speed manner, the second-stage screw rotor 13 is driven by the high-pressure-stage driving motor 15 in a variable speed manner, and the displacement is adjusted by the movable adjusting valve 16, so that the medium-high pressure screw compressor can be suitable for different working environments and has wider application fields. Specifically, the rotation speeds of the low-pressure stage drive motor 14 and the high-pressure stage drive motor 15 can be accurately changed to each revolution by the control of the control unit, so that the adjustment of the displacement can be accurately changed to a very small change, and the medium-high pressure screw compressor can be applied to working environments with very high requirements on the adjustment accuracy of the displacement, such as the manufacturing of precision instruments in aerospace, fuel cells, refrigerators, air-conditioning refrigerators and the like. Taking an air-conditioning refrigerator as an example, the adjustment of the air-conditioning refrigerator is more accurate, and each degree of increase and decrease can slightly change the internal gas compression. In addition, the valve body 161 is moved in the chamber by rotating the rotating shaft 162, and compared with an adjusting mode of changing the rotating speed of the driving motor, the adjusting mode of the adjusting mode enables the degree of change of the air displacement during the moving process of the valve body 161 to be larger, belongs to a coarse adjusting mode, and is particularly suitable for working environments with low requirements on air displacement adjusting precision, such as food, light textile industry, glass bottle blowing processing and the like. The rotation of the rotating shaft 162 can be controlled hydraulically and manually, and particularly, the medium-high pressure screw compressor which controls the regulating valve 16 manually is suitable for working environments where power supply is stopped, the compressor is stopped, and power supply is difficult, such as in the field, mining areas, and other areas, or in environments where the driving motor is driven by a gas engine and the regulating valve 16 cannot be regulated by using hydraulic pressure and a stepping motor, so that the regulating valve 16 can be regulated manually. Furthermore, the use of the manually controlled compressor saves the use costs of the fittings, in particular the hydraulic arrangement. In specific implementation, one end of the rotating shaft 162 is connected to the valve body 161, and the other end of the rotating shaft extends to the outside of the housing 1 and is provided with a handle 163 for rotating the rotating shaft 162 to move the adjusting valve 16, so that manual adjustment from the outside of the high-pressure screw compressor is facilitated.

As a preferred embodiment of the present inventionThe first chamber 11 is provided with the regulating valve 16 for illustration, and certainly, the second chamber may also be provided with the regulating valve 16, which is not described herein again. The exhaust volume of the first chamber 11 adopts a formulaWherein C is the displacement, X is the regulating coefficient of the regulating valve 16, n is the rotating speed of the low-pressure driving motor 14, T is the rated torque of the low-pressure driving motor 14, eta is the efficiency, and Q_SIs the initial air inflow of the air inlet end 121, t is the running time of the low-voltage level driving motor 14, m is the initial air inlet mass, omega_sFor the isentropic compression process specific work, n_tThe number of revolutions of the low pressure stage drive motor 14 required for each cycle of the first stage screw rotor 12. Specifically, the rated torque T of the low-voltage stage drive motor 14 is constant after it is determined. Efficiency is the total efficiency in the low pressure stage compression process, which mainly includes the product of motor efficiency, gas-to-volume ratio efficiency, internal leakage efficiency, etc. X is a regulation coefficient of the regulation valve 16, and specifically, since a movement length of the regulation valve 16 in the first chamber 11 is determined, a change in the amount of exhaust gas is a certain value every time the regulation valve 16 moves the same distance, for example, the regulation coefficient X of the regulation valve 16 is 0.5 when the regulation valve 16 moves from the initial end portion to the intermediate position, and the regulation coefficient X of the regulation valve 16 is 0.9 when the regulation valve 16 moves from the initial end portion by a length of one-tenth. The rotation speed n of the low-pressure stage drive motor 14 is changed or the regulating valve 16 is moved to change X by the above formula to adjust the displacement of the medium-high pressure screw compressor, but it is also possible to adjust the displacement by changing the rotation speed n of the low-pressure stage drive motor 14 and moving the regulating valve 16 at the same time. The cooperation of two kinds of regulation modes is used to make well high-pressure screw compressor switch over at will in the mode of fine setting and coarse adjustment displacement more humanized, for example, can adjust driving motor's rotational speed to a definite value, make initial displacement be in the floating range around required displacement volume, when the displacement needs roughly to change, only need just can realize through removing governing valve 16 for driving motor can guarantee certain energy-conserving effect.

The control unit controls the low-voltage stage driving motor 14 and the high-voltage stage driving motor 15 mainly in the following modes: and a detection device arranged in the compression chamber and used for measuring pressure and/or temperature change in the form of signals, wherein the signal converter is connected with the control unit and the detection device and transmits the signals measured by the detection device to the control unit, and the control unit adjusts the speed of the driving motor to provide the required air flow conveying speed and pressure. In the invention, the low-voltage stage driving motor 14 and the high-voltage stage driving motor 15 independently drive each stage of screw rotor, and each driving motor is not mechanically connected. The characteristics of each drive motor are matched to the respective compression stage, i.e. the low pressure stage drive motor 14 is matched to the low pressure compression of the first stage screw rotor 12 in the first chamber 11, and the high pressure stage drive motor 15 is matched to the high pressure compression of the second stage screw rotor 13 in the second chamber. When the rotation speed of the high-pressure stage driving motor 15 is adjusted, the exhaust amount of the second chamber can be adjusted; when the rotation speed of the low-pressure stage drive motor 14 is adjusted, the amount of exhaust gas in the first chamber 11 can be adjusted, and when the amount of exhaust gas in the first chamber 11 is changed, the amount of intake air entering the second chamber from the intake port 131 is changed, so that the amount of exhaust gas in the second chamber is changed. Of course, the two drive motors can be adjusted simultaneously to achieve the desired displacement at a faster rate.

In a preferred embodiment of the present invention, the control unit includes a frequency converter, and the frequency converter controls the operating speed and power parameters of the low-voltage stage driving motor 14 and the high-voltage stage driving motor 15. The speed of the low-stage drive motor 14 and the high-stage drive motor 15 is controlled by the frequency converter. The basic control parameter is the desired final supply air pressure or volume. The speed of each stage of the drive motor is increased to produce a greater airflow or decreased to produce a smaller airflow. The maximum rotational speed is limited to a predetermined level based on mechanical considerations. The minimum speed can be predetermined or determined by measuring the delivery temperature for each compression stage. For example, as the rotor speed of any stage slows, the efficiency of that stage decreases, resulting in an increase in temperature. This control of the frequency converter is achieved by continuously measuring the pressure and temperature of the air flow delivery at each stage, as well as the input torque and speed at each stage. These parameters are measured using a detection device and transmitted to a frequency converter, which processes the signals and sets the drive motor to a corresponding speed in order to obtain the desired delivery air flow and pressure.

In a preferred embodiment of the present invention, the detecting device is a multi-parameter detecting integrated composite sensor, the composite sensor itself is an assembly that can be understood as a whole, and two or more sensor units for detecting different physical quantities are integrated in the assembly, and the multi-parameter detecting integrated composite sensor is disposed at the air inlet 121, the air outlet 122, the air inlet 131 or the air outlet 132 in the present invention, and preferably, the multi-parameter detecting integrated composite sensor is disposed at the air inlet 121, the air outlet 122, the air inlet 131 and the air outlet 132, so that the change of the physical quantities of the first chamber 11 and the second chamber caused by the initial air inlet and the final air outlet can be detected. The multi-parameter detection integrated composite sensor can at least detect pressure and temperature signals so as to transmit the signals such as pressure or temperature to the control unit, and the control unit can adjust the low-voltage-level driving motor 14 and/or the high-voltage-level driving motor 15 according to the signals.

As a preferred embodiment of the present invention, as shown in fig. 1 to 2, the first chamber 11 is provided with the regulating valve 16, the valve body 161 includes an exhaust amount regulating valve portion 1611 provided near the intake end 121 and a gas capacity ratio regulating valve portion 1612 provided near the exhaust port 122, the exhaust amount regulating valve portion 1611 is screwed to the rotating shaft 162, the exhaust amount regulating valve portion 1611 has a first position in contact with the gas capacity ratio regulating valve portion 1612 and a second position in which it is disengaged, and the rotating shaft 162 is rotated to disengage the exhaust amount regulating valve portion 1611 from the gas capacity ratio regulating valve portion 1612 to form an exhaust passage 1613 between the exhaust amount regulating valve portion 1611 and the gas capacity ratio regulating valve portion 1612, and gas in the first chamber 11 can be exhausted through the exhaust passage 1613; the air-volume ratio adjusting valve portion 1612 is sleeved on the rotating shaft 162 and can slide on the rotating shaft 162, so that the adjusting valve 16 can adjust the air-volume ratio of the medium-high pressure screw compressor. The regulating valve 16 integrates dual functions of air displacement regulation and air-to-volume ratio regulation, and compared with a structure that two valves, namely the air displacement regulating valve 16 and the air-to-volume ratio regulating valve 16, are arranged in the compression chamber at the same time, the invention has simple structure, is beneficial to saving the internal space of the compression chamber, and also ensures that the air displacement and the air-to-volume ratio can be regulated at the same time by rotating one regulating valve 16.

Specifically, the air displacement adjustment valve portion 1611 is screwed and tightened with the rotation shaft 162, the air volume ratio adjustment valve portion 1612 is slid on the rotation shaft 162 on the side of the air intake end 121, the air volume ratio adjustment valve portion 1612 is pushed toward the air displacement adjustment valve portion 1611 by the elastic member 164, and the air volume ratio adjustment valve portion 1612 is always held in contact with the air displacement adjustment valve portion 1611 when the air volume ratio adjustment valve portion 1612 is not fixed in position, so that when the air volume ratio adjustment valve portion 1612 is to be moved toward the air intake end 121, that is, when the air volume ratio is to be decreased, the air displacement adjustment valve portion 1611 is moved toward the air intake end 121 by rotating the rotation shaft 162, and the air volume ratio adjustment valve portion 1612 is moved together with the air displacement adjustment valve portion 1611; when the air-volume ratio adjustment valve portion 1612 moves toward the exhaust port 122, that is, when the air-volume ratio is increased, the air-volume ratio adjustment valve portion 1612 is always urged toward the exhaust amount adjustment valve portion 1611 by the elastic member 164, and therefore, the air-volume ratio adjustment valve portion 1612 moves toward the exhaust port 122 by rotating the rotating shaft 162. Therefore, when the gas capacity ratio adjustment valve portion 1612 is not fixed in position, the gas capacity ratio adjustment valve portion 1612 and the air displacement adjustment valve portion 1611 can be moved together in any direction by rotating the rotating shaft 162. When the air volume ratio adjusting valve portion 1612 is fixed in position, if the air displacement adjusting valve portion 1611 is moved by the rotating shaft 162, the air displacement is changed.

As a preferred example in the present embodiment, the gas capacity ratio adjustment valve portion 1612 has a plurality of positioning portions 1614 provided along the axial direction of the screw rotor, and the medium-high pressure screw compressor further includes a fixing device 18 fixed to the first chamber 11, and when the gas capacity ratio adjustment valve portion 1612 slides on the rotating shaft 162, the fixing device 18 can engage with one of the plurality of positioning portions 1614 to fix the gas capacity ratio adjustment valve portion 1612. The position of the positioning portion 1614 in the sliding direction on the outer periphery of the gas capacity ratio adjustment valve portion 1612 and the position inside the first chamber 11 are determined so as to correspond to a predetermined gas capacity ratio. The gas-to-capacity ratio change is achieved by fixing the gas-to-capacity ratio adjustment valve portion 1612 at a different position by the fixing means 18. Since the air-capacity ratio adjusting valve portion 1612 can be moved in any sliding direction by the rotating shaft 162, an appropriate fixing position can be selected conveniently.

As a preferred example in the present embodiment, as shown in fig. 3, the medium-high pressure screw compressor further includes a circulation pipeline 17, one end of the circulation pipeline 17 is communicated with the exhaust channel 1613, and the other end is communicated with the gas inlet end 121 of the first chamber 11, so that the circulation compression of gas can be realized, the gas consumption can be reduced, and the cost can be saved.

The invention also provides a control method of the air displacement of the medium-high pressure screw compressor, which comprises the following steps:

the method comprises the following steps: setting a plurality of initial pressure values and the rotating speed of a driving motor of each stage corresponding to the initial pressure values in a compression chamber in a medium-high pressure screw compressor;

step two: detecting the exhaust pressure of the compression chamber at the exhaust end 132 through a detection device, and comparing the exhaust pressure with the initial pressure value;

step three: when the discharge pressure is equal to the initial pressure value, the gas is delivered and the driving motor of each stage is operated at the maximum speed with the discharge capacity adjustment valve portion 1611 abutting against the gas capacity ratio adjustment valve portion 1612, i.e., with the discharge passage 1613 closed;

step four: the rotating speed of each stage of driving motor is adjusted through the frequency converter to change the air displacement, so that the expected air displacement is realized.

The invention also provides a control method of the air displacement and the air-to-volume ratio of the medium-high pressure screw compressor, which comprises the following steps:

the method comprises the following steps: rotating the rotating shaft 162 to slide the gas-to-capacity ratio adjusting valve portion 1612 on the rotating shaft 162 to change the gas-to-capacity ratio in the compression chamber, and fixing the gas-to-capacity ratio adjusting valve portion 1612 slid in place by engaging the fixing means 18 with the positioning portion 1614 to make the gas-to-capacity ratio in the compression chamber constant;

step two: rotating the rotating shaft 162 to move the air displacement adjusting valve portion 1611 in the axial direction of the screw rotor, disengaging the air displacement adjusting valve portion 1611 from the air capacity ratio adjusting valve portion 1612, opening the air discharge passage 1613, and discharging a part of the compressed air introduced into the compression chamber through the air discharge passage 1613;

step three: the gas exhausted from the exhaust channel 1613 is returned to the intake end 121 via the recirculation line 17 and is recompressed.

The method can be realized by adopting or referring to the prior art in places which are not described in the invention.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments.

The above description is only an example of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.