阅读说明：本技术 一种调整转子平衡的方法 (Method for adjusting rotor balance ) 是由 张金铠 于 2021-08-11 设计创作，主要内容包括：本发明应用在大型工业转子低速动平衡和高速动平衡试验领域,具体提供了一种调整转子平衡的方法,该方法具体包括如下步骤：1)将转子安装在低速平衡机上,对初始状态的转子主轴进行挠度值恢复调水平；2)升速驱动转子对其进行低速调平衡：以设定转速n驱动转子,记录低速平衡机显示的剩余不平衡量值a,基于a值对转子进行加重或者减重,直至a满足要求,低速调平衡结束；3)将低速调平衡的转子安装在高速平衡机上对其进行调平衡：包括记录高速平衡机显示的剩余不平衡量值,基于该值对转子进行加重或者减重,直至运转至最大连续转速和超转转速下平衡机显示的振动速度符合要求,高速调平衡结束。(The invention is applied to the field of low-speed dynamic balance and high-speed dynamic balance tests of large-scale industrial rotors, and particularly provides a method for adjusting the balance of a rotor, which specifically comprises the following steps: 1) mounting the rotor on a low-speed balancing machine, and restoring and leveling the deflection value of the rotor spindle in an initial state; 2) the rotor is driven by the speed rising to carry out low-speed balance adjustment: driving the rotor at a set rotating speed n, recording a residual unbalance value a displayed by the low-speed balancing machine, and weighting or lightening the rotor based on the value a until the value a meets the requirement and the low-speed balance adjustment is finished; 3) installing a rotor with low-speed balance adjustment on a high-speed balancing machine to adjust balance: recording the residual unbalance value displayed by the high-speed balancing machine, weighting or losing the rotor based on the value until the vibration speed displayed by the balancing machine meets the requirement when the rotor is operated to the maximum continuous rotating speed and the over-rotating speed, and finishing the high-speed balancing.)

1. A method of balancing a rotor, the rotor comprising a main shaft and a plurality of impellers disposed on the main shaft, the method comprising:

s1: mounting the rotor on a low-speed balancing machine, and restoring and leveling the deflection value of the rotor spindle in an initial state;

s2: the rotor is driven by the speed rising to carry out low-speed balance adjustment: driving the rotor at a set rotating speed n, recording a residual unbalance value a displayed by the low-speed balancing machine, and weighting or lightening the rotor based on the value a until the value a meets the requirement and the low-speed balance adjustment is finished;

s3: installing a rotor with low-speed balance adjustment on a high-speed balancing machine to adjust balance: and respectively driving the rotor at the maximum continuous rotating speed and the over-rotating speed, recording the vibration speed value displayed by the high-speed balancing machine at the corresponding rotating speed, weighting or lightening the rotor based on the value, enabling the vibration speed value displayed by the balancing machine at the maximum continuous rotating speed and the over-rotating speed to meet the requirement, and finishing the high-speed balancing.

2. A method of adjusting rotor balance as set forth in claim 1, wherein: in step S1, the method for restoring the deflection value to leveling includes the following steps:

s101: abutting a measuring head of the dial indicator against the edge of the lower end of the rotor impeller, and zeroing data of the dial indicator; the impeller is selected to be located close to the axial middle position of the main shaft, and the periphery of the impeller is a smooth surface;

s102: and driving the rotor at a low speed of 50-100rpm to obtain the variation h of the pointer of the dial indicator, and recovering the deflection value of the main shaft to be in a horizontal state when the variation h is constant.

3. A method of adjusting rotor balance as claimed in claim 1, wherein:

step S2 further includes a detection step, which specifically includes,

1) the rotor with low speed balance adjustment is static for more than or equal to 12 hours;

2) the rotor was rotated at 50-100rpm and the constant deflection value change h1 was measured with a dial gauge: after the rotor is static, the lower end of an impeller of the rotor is in contact with a dial indicator, data of the dial indicator is reset to zero, and the impeller is selected to be positioned at the middle part of a main shaft of the rotor; driving the rotor to rotate at the rotating speed of 50-100rpm until the constant variation h1 of the pointer of the dial indicator is obtained;

3) continuing to drive the rotor at a set rotating speed n, and acquiring a residual unbalance value a1 displayed by the low-speed balancing machine at the rotating speed;

4) if the difference between h1 and h and the difference between a1 and a meet the requirements, the rotor is in a balanced state at low speed, otherwise, the rotor returns to check machine defects, and the steps S1 and S2 are executed again after the defects are removed.

4. A method of adjusting rotor balance as claimed in claim 1, wherein: in S3, the rotor is preprocessed before balancing by the high-speed balancing machine, and the preprocessing steps are:

1) recording a residual unbalance value a2 displayed on the high-speed balancing machine after the rotor operates for more than or equal to 2 hours at a set rotating speed n;

2) comparing a2 with the residual unbalance value a when the low speed balance is qualified in S2, if the difference range meets the requirement, carrying out high speed balance adjustment, otherwise, adjusting the residual unbalance value of the rotor to meet the requirement.

5. A method of adjusting rotor balance as set forth in claim 4, wherein: the method for adjusting the residual unbalance value of the rotor comprises the steps of increasing the speed of the rotor from a set rotating speed n of a high-speed balancing machine to a specific rotating speed, wherein the specific rotating speed is the speed reduced by 500rpm from a first-order critical rotating speed; repeatedly increasing and decreasing the rotating speed to release the stress of the rotor until the residual unbalance value a2 meets the requirement when the rotating speed n is set, and finishing the adjustment; otherwise, the rotor is accelerated to the maximum continuous speed through the first-order critical speed until the rotor low-speed residual unbalance value a2 meets the requirement.

6. A method of adjusting rotor balance as claimed in claim 1, wherein: and step S4, after the rotor with high speed balance adjustment is static for 12 hours, the rotor is accelerated to the maximum continuous rotating speed and the corresponding rotating speed vibration speed value of the rotor is recorded with the rotating speed exceeding the maximum continuous rotating speed, the value is compared with the value recorded in the first high speed balance test in the step S3, and if the difference range meets the requirement, the high speed balance test is ended.

7. A method of adjusting rotor balance as claimed in claim 1, wherein: the shaft diameters of two ends of a rotor rotating shaft on the low-speed balancing machine are supported by a group of roller groups which are oppositely arranged, and the roller groups are arranged on a swing frame of the low-speed balancing machine; the shaft diameters of two ends of the rotor on the high-speed balancing machine are respectively sleeved inside bearings, and the bearings are fixed on a rack of the high-speed balancing machine.

Technical Field

The invention is applied to the field of low-speed dynamic balance and high-speed dynamic balance tests of large industrial rotors, and particularly provides a method for adjusting rotor balance.

Background

Before the rotor leaves a factory, a balance test is needed to adjust the balance of the rotor, for example, a large-sized rotor, a half-coupling is arranged on a shaft head of the rotor, the weight of the rotor is about 30t, the maximum rotating diameter of the rotor is about 1.6m, the shaft diameter sizes of two sides of the rotor are 320mm, the maximum continuous rotating speed of the rotor is 3500rpm, and the bearing span of two sides is about 6 m. Because the rotor has heavy weight and long span, when the shaft diameter parts at two ends of the rotor are supported for balance adjustment, the middle section part of the rotor in the axial direction has larger deflection value, and when the rotor is changed from a static state to a dynamic rotating state, the deflection change of the central part of the rotor is found to be 0.15-0.20mm through measurement.

In the existing method for balancing a large rotor, the deflection change of the rotor in static and dynamic running states is generally considered to be small, and the deflection change factor of the rotor is not considered. Therefore, when the large rotor is subjected to balance tests on a low-speed balancing machine and a high-speed balancing machine, the balance operation such as weighting or de-weighting is carried out on the rotor after the target rotating speed is reached according to a conventional method, and the influence of the static deflection value of the initial state of the rotor on a balance adjusting result is ignored by the balance adjusting method. The result shows that the rotor balanced by the traditional method always changes the unbalance magnitude and the phase in the production process of the large-scale steam turbine, even if the rotor is adjusted to be balanced to be qualified according to the condition, the rotor is accelerated to the balanced rotating speed after being kept still for a period of time, and the remaining unbalance magnitude of the rotor is still greatly changed, so that the displayed remaining unbalance magnitude is poor in repeatability in the operation process of the large-scale rotor every time, and the production process cannot be smoothly carried out.

Disclosure of Invention

In view of the above problems, the present invention provides a method for adjusting the balance of a rotor, which is suitable for a large steam turbine and a compressor, the rotor including a main shaft and a plurality of impellers disposed on the main shaft, comprising the steps of,

s1: mounting the rotor on a low-speed balancing machine, and restoring and leveling the deflection value of the rotor spindle in an initial state;

s2: the rotor is driven by the speed rising to carry out low-speed balance adjustment: driving the rotor at a set rotating speed n, recording a residual unbalance value a displayed by the low-speed balancing machine, and weighting or lightening the rotor based on the value a until the value a meets the requirement and the low-speed balance adjustment is finished;

s3: installing a rotor with low-speed balance adjustment on a high-speed balancing machine to adjust balance: and respectively driving the rotor at the maximum continuous rotating speed and the over-rotating speed, recording the vibration speed value displayed by the high-speed balancing machine at the corresponding rotating speed, weighting or lightening the rotor based on the value, enabling the vibration speed value displayed by the balancing machine at the maximum continuous rotating speed and the over-rotating speed to meet the requirement, and finishing the high-speed balancing.

Further, in step S1, the method for restoring the deflection value and leveling includes the following steps:

s101: abutting a measuring head of the dial indicator against the edge of the lower end of the rotor impeller, and zeroing data of the dial indicator; the impeller is selected to be located close to the axial middle position of the main shaft, and the periphery of the impeller is a smooth surface;

s102: and driving the rotor at a low speed of 50-100rpm to obtain the variation h of the pointer of the dial indicator, and recovering the deflection value of the main shaft to be in a horizontal state when the variation h is constant.

Further, step S2 includes a detection step, which specifically includes,

1) the rotor with low speed balance adjustment is static for more than or equal to 12 hours;

2) the rotor was rotated at 50-100rpm and the constant deflection value change h1 was measured with a dial gauge: after the rotor is static, the lower end of an impeller of the rotor is in contact with a dial indicator, data of the dial indicator is reset to zero, and the impeller is selected to be positioned at the middle part of a main shaft of the rotor; driving the rotor to rotate at the rotating speed of 50-100rpm until the constant variation h1 of the pointer of the dial indicator is obtained;

3) continuing to drive the rotor at a set rotating speed n, and acquiring a residual unbalance value a1 displayed by the low-speed balancing machine at the rotating speed;

4) if the difference between h1 and h and the difference between a1 and a meet the requirements, the rotor is in a balanced state at low speed, otherwise, the rotor returns to check machine defects, and the steps S1 and S2 are executed again after the defects are removed.

Further, in S3, the rotor is preprocessed before the balancing by the high speed balancing machine, where the preprocessing step is:

1) recording a residual unbalance value a2 displayed on the high-speed balancing machine after the rotor operates for more than or equal to 2 hours at a set rotating speed n;

2) comparing a2 with the residual unbalance value a when the low speed balance is qualified in S2, if the difference range meets the requirement, carrying out high speed balance adjustment, otherwise, adjusting the residual unbalance value of the rotor to meet the requirement.

Further, the method for adjusting the residual unbalance value of the rotor comprises the steps of increasing the set rotating speed n of the rotor from the high-speed balancing machine to a specific rotating speed, wherein the specific rotating speed is the first-order critical rotating speed reduced by 500 rpm; repeatedly increasing and decreasing the rotating speed to release the stress of the rotor until the residual unbalance value a2 meets the requirement when the rotating speed n is set, and finishing the adjustment; otherwise, the rotor is accelerated to the maximum continuous speed through the first-order critical speed until the rotor low-speed residual unbalance value a2 meets the requirement.

And further, step S4, after the rotor with high speed balance adjustment is static for 12 hours, the rotor is accelerated to the maximum continuous rotating speed and the corresponding rotating speed vibration speed value of the rotor is recorded with the rotating speed exceeding the maximum continuous rotating speed, the value is compared with the value recorded in the first high speed balance test in the step S3, and if the phase difference range meets the requirement, the high speed balance test is ended.

Further, the shaft diameters of two ends of the rotor rotating shaft on the low-speed balancing machine are supported through a group of roller groups which are arranged oppositely, and the roller groups are arranged on the swing frame of the low-speed balancing machine; the shaft diameters of two ends of the rotor on the high-speed balancing machine are respectively sleeved inside bearings, and the bearings are fixed on a rack of the high-speed balancing machine.

The balancing method for the large rotor is suitable for rotors with large diameters, long spans and heavy weights of compressors or turbines and is also suitable for large rotors provided with half couplings in the balancing process. By adopting the method, the low-speed and high-speed dynamic balance test of the rotor can be efficiently carried out, the balance operation efficiency is improved, the rotor balancing quality is further improved, the operation is more stable through the application on the rotor of the large-scale unit, the working efficiency of large-scale equipment such as a steam turbine is improved, the stability of the large-scale unit is improved, and the service life of the large-scale unit is prolonged.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the production operation of a rotor of a large compressor or a steam turbine, the rotor needs to be adjusted and balanced, and the adjustment and balance comprises two test sections, namely low-speed adjustment and balance on a low-speed balancing machine and high-speed adjustment and balance on a high-speed dynamic balancing machine. The rotor balance test method provided by the invention can guide the dynamic balance process of a large rotor at low speed and high speed, ensure the balance quality and shorten the product manufacturing period, and the technical scheme of the application is also suitable for balancing the shaft end of the rotor directly provided with the half coupling, and comprises the following specific steps:

s1: the rotor is arranged on a low-speed balancing machine, because the large rotor is heavy and the mass is mainly distributed in the axial middle part of the main shaft, and the middle part has a static deflection value, the deflection value of the main shaft of the rotor in the initial state needs to be restored and leveled; the method is specifically adjusted by the following method,

s101: abutting a measuring head of the dial indicator against the edge of the lower end of the rotor impeller, and zeroing data of the dial indicator; the impeller is selected to be located close to the axial middle position of the main shaft, and the periphery of the impeller is a smooth surface; the dial indicator is fixedly supported by the setting support, and because the gap distance between the impeller and the impeller is small, and the length of a measuring rod for supporting the measuring head of the dial indicator is limited, the measuring head of the dial indicator is selected to be abutted against the periphery of the impeller.

S102: and driving the rotor at a low speed of 50-100rpm to obtain the variation h of the pointer of the dial indicator until the variation h is constant, and then recovering the static deflection value of the main shaft to a horizontal state.

The flexibility state of the rotor is different according to the difference of the diameter, span, weight, connection structural form of each section of the main shaft of the rotor and the like, but a large number of experiments show that the rotors of different types need to run for 1-2 hours at the rotating speed, the flexibility value of the rotors is basically stable and unchanged, and the static flexibility recovery of the rotors is explained under the condition that the flexibility value is unchanged.

S2: the rotor is driven by the speed rising to carry out low-speed balance adjustment: specifically, the rotor is driven at a set rotating speed of 300-;

s3: and (3) mounting the rotor subjected to low-speed balance adjustment on a high-speed balancing machine to perform high-speed balance adjustment on the rotor, operating the rotor on the high-speed balancing machine at a specified rotating speed, wherein the specified rotating speed specifically comprises a maximum continuous rotating speed and an over-rotating speed specified according to an API standard, and performing weighting or weight-reducing operation on the rotor based on the vibration speed required by the standard at the specified speed until the vibration speed displayed by the balancing machine at the maximum continuous rotating speed and the over-rotating speed meets the requirement, and finishing the high-speed dynamic balance adjustment.

The API standard specifies the maximum continuous rotational speed: the maximum rotational speed at which the machine can be run continuously after manufacture and during testing. For compressors driven by variable speed drives, this speed is 105% of the nominal speed. For a constant speed motor driven compressor, this speed is dependent on the synchronous speed of the motor. The rotor is balanced in the low speed state based on the residual unbalance value displayed by the balancer, and the change of the value is not obvious in the high speed state, so that the vibration speed parameter is selected to evaluate the balance state of the rotor.

In view of the fact that the low-speed balance test section plays a crucial role in the whole balance test process of the whole rotor, the test cost of the high-speed dynamic balancing machine is high, if the low-speed test section is not subjected to the high-speed test section, the rotor cannot rotate at a preset speed under high-speed rotation due to the non-uniformity of the weight of the rotor, and the quality of equipment of a steam turbine and other units is serious due to the large operation swing amplitude. As an improvement of the scheme, after the dynamic balance of the low-speed balance is qualified, the low-speed balance test process is verified by the following method, which specifically comprises the following steps,

1) the rotor with low speed balance adjustment is static for more than or equal to 12 hours;

2) the rotor was rotated at 50-100rpm and the constant deflection value change h1 was measured with a dial gauge: after the rotor is static, the lower end of an impeller of the rotor is in contact with a dial indicator, data of the dial indicator is reset to zero, and the impeller is selected to be positioned in the middle of a main shaft of the rotor; the rotor is driven to rotate at the rotating speed of 50-100rpm until the dial indicator variable quantity h1 is unchanged;

3) continuously driving the rotor at the set rotating speed of 300-500rpm to obtain the residual unbalance value a1 displayed by the low-speed balancing machine at the rotating speed;

4) if the difference between h1 and h and the difference between a1 and a meet the requirements, the rotor is in a balanced state at low speed, otherwise, the rotor returns to check machine defects, and the steps S1 and S2 are executed again after the defects are removed.

The difference between the two tests in the test times of more than 98% is found to meet the requirements through the verification, and the difference is checked by workers on site under the condition that the difference does not meet the requirements, so that the mechanical defect of the rotor is often found, and the operations of the steps S1 and S2 are carried out again after the defect is removed.

As another embodiment of the present invention, in S3, the rotor is preprocessed before the high-speed balancing machine adjusts the balance, and the preprocessing includes:

1) recording a residual unbalance value a2 displayed on the high-speed balancing machine after the rotor operates for more than or equal to 2 hours at a set rotating speed n;

2) comparing a2 with the residual unbalance value a when the low speed balance is qualified in S2, if the difference range meets the requirement, carrying out high speed balance adjustment, otherwise, adjusting the residual unbalance value of the rotor to meet the requirement.

The low-speed balancing machine adopts the roller to support the rotor, and particularly, the low-speed balancing machine is provided with a group of oppositely arranged swing frames, each swing frame is used for supporting the shaft diameters of two ends of the rotor, a group of oppositely arranged supporting rollers are arranged on each swing frame, each roller is respectively provided with a supporting point for the shaft diameters, and the shaft diameters rotate on a supporting part formed by the group of rollers under the action of a driving motor. The high-speed balancing machine adopts a sliding bearing to support the rotor, the balancing machine is provided with two supporting parts which respectively provide two supporting points for the rotor, each supporting part comprises a frame, a supporting bearing is arranged on the frame, and the shaft diameters of two end parts of the rotor are respectively arranged in the bearing and rotate under the action of a driving motor. The working principle of supporting the rotor by the two balancing machines is different, the rotor needs to be verified and adjusted from the low-speed balancing machine to the high-speed balancing machine, if the difference range of the residual unbalance magnitude meets the requirement, a high-speed balancing test is carried out, and otherwise, the residual unbalance magnitude of the rotor is adjusted to meet the requirement.

In the step, the rotor is balanced on the low-speed balancing machine, the balancing can be carried out only after the deflection value of the rotor is recovered in the high-speed balancing machine, and if the residual unbalance value does not meet the requirement, the stress of the rotor needs to be adjusted, so that the stress is fully released to meet the requirement of the low-speed residual unbalance value. Based on the state, the method for adjusting the residual unbalance value of the rotor comprises the steps of increasing the speed of the rotor from the set rotating speed of 300-500rpm of the high-speed balancing machine to a specific rotating speed which is within the range of reducing the first-order critical rotating speed by 500rpm, repeatedly increasing and reducing the rotating speed to release the stress of the rotor until the low-speed residual unbalance value a2 meets the requirement, and ending the adjustment; otherwise, the rotor is continuously accelerated to the maximum continuous rotating speed through the first-order critical rotating speed in the high-speed balancing machine, the rotor is thrown in a high-rotating-speed state, and the stress is fully released until the low-speed residual unbalance value a2 of the rotor meets the requirement.

The rotor qualified in the test on the low-speed balancing machine is installed on the high-speed dynamic balancing machine swing, and the high-speed dynamic balancing connector is installed on the end face of the half coupling and needs to be subjected to surface beating inspection independently, so that the surface beating data of the outer circle of the connector is not larger than 0.05 mm. And scraping the bearing clearance and the bearing oil inlet oil bag, and pressing the bearing gland to ensure that the interference data meets the requirements. And after the rotor and the high-speed swing enter the high-speed balance vacuum cabin, connecting the universal joint of the driving motor with the high-speed balance joint of the rotor, and performing meter reading on the high-speed dynamic balance joint of the rotor again after connection, wherein the meter reading data of the outer circle of the joint is required to be not more than 0.05mm, and if the rotor and the high-speed swing enter the high-speed balance vacuum cabin, the condition of the joint closing is adjusted.

As another embodiment of the present invention, in order to check the accuracy of the above test, after the high speed balancing is qualified, the rotor with the high speed balancing is stopped for 12 hours, and then the rotor is accelerated to the maximum continuous rotation speed and the over-rotation speed, and the rotation speed vibration speed value of the rotor is recorded, and the value is compared with the value recorded in the first high speed balancing test in S3, if the difference range meets the requirement, the high speed balancing test is ended.

Experiments show that the number of the balance rotors is 100 by the method, and when the balance rotors are found to be mounted on a large-scale steam turbine unit in the field working process subsequently, the vibration detection probe on the steam turbine unit is used for measuring the X axis and the Y axis of the main shaft of the rotor, the vibration amplitude standards of the main shaft of the rotor are found to meet the requirements, and the rotor balance qualified rate reaches 100%. The rotor in the comparison experiment is not subjected to balance adjustment and deflection recovery values of the initial state of the rotor main shaft of the low-speed balancing machine and the high-speed balancing machine, the rotor which is weighted or lightened and balanced is directly subjected to balance adjustment, the vibration amplitude variation measured by running on a steam turbine is large, and the qualification rate is only 40%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.