[problem] the scene for the removal of centrifugal fan dynamic balancing method?
[answer] new dry production line, between the various types of centrifugal fan installed capacity accounted for 30% of the total power production line to 40%, to strengthen the online maintenance and maintenance of centrifugal fan, it is very important; especially the fan impeller abrasion caused by unbalanced rotor, which leads to the wind machine amplitude increase, seriously affect the normal operation of production; therefore, how in the construction site for the wind machine dynamic balance and eliminate imbalances, in fan years of maintenance and management work, the author summed up a set of effective and simple method to identify the location of the impeller; tap by drawing method, and in a position add weight to balance the scavenging fan.
1, introduction
To make the rotor rotor dynamic balance, the key is to find out the position of the impeller, and to determine the quality of the balance block; using the drawing method to find a balance, the specific steps are as follows:
(1) open the fan, stable operation, in the most able to reflect the vibration of the wind turbine M (such as the bearing seat, etc.), with the vibration meter to measure the amplitude of A0, after recording downtime;
(2) the impeller front (or rear) circle of 3 equal, respectively, for the 1 points, 2 points, 3 points;
(3) at the point of the clip on the pre production of the block P (according to the size of the fan impeller to determine the quality of the general mp=150g ~ 300g), repeat step 1, the measured M point amplitude A1;
(4) change the position of the clamping block P to 2 and 3, repeat step 3, and then measure the M point amplitude A2, A3;
(5) mapping; circle with radius A0, Center for O, the circle is divided into 3 parts, respectively, denoted as O1, O2, O3; O1 is central, A1 is the radius of arc; with O2 as the center, A2 is the radius of arc; with O3 as the center, a radius of A3 for the above 3 arc; arc respectively to B, C, D three;
(6) BCD angina O4, O4 point is easy, OO4 connection and extending the circle of O in O5 point, O5 point is the counterweight block; side length of OO4 is L, then O5 is m with counterweight =mp * A0/2L;
(7) the fan impeller front plate (or rear disc) on the circumference to identify the actual O5 position, the weight is m with iron welding; thus, fan balancing finish;
2, examples
Shandong building materials Co. Ltd. 1000t/d cement clinker production line of grate cooler is equipped with 1 sets of air blower, the wind turbine technology index;
The basic structure of the air blower is shown; fan bearings are double row spherical roller bearing, the foundation for the concrete foundation for the rigid rotor rotor; the fan installed before installation due to rapid, only roughly do dynamic balance test and working medium amount of dust is too large, causing serious wear of impeller the result, in May 2002, due to large amplitude; fan vibration amplitude increase, so the scene for the 1 operation risk, 2, 3, 4, four measuring points were tested, the test results are shown in table 2;
On the basis of the re strengthening of the fan base, excluding the factors such as mechanical looseness and bearing failure, the main cause of vibration is the unbalance of the rotor;
(1) the selection of the measuring point; the #4 measuring point is close to the impeller, and the change of the vibration value can directly reflect the size of the unbalance of the impeller, so the #4 measuring point is selected as the measuring point M, and the amplitude of A0=210 is measured by m;
(2) according to the size and vibration of the fan, as well as the operation and maintenance experience, decided to try to add weight mp=180g;
(3) the impeller on the front panel on the circumference of the balance is divided into 3 equal parts, respectively for 1 points, 2 points, 3 points, and in turn the M amplitude of A1=226 m; A2=208 m; A3=256 m;
(4) as mentioned before mapping; O4 is a position O5 with some heavy, measured OO4 long L=25 m, so the actual withcounterweight m with =mp * A0/2L=180 * 210/ (2 * 25) =756g;
(5) the 756g weight is welded on the front plate O5, and the vibration value of the M point is measured as m after the start, and the test results of the measuring points for the dynamic balance of the centrifugal fan are shown in table 2;
3, conclusion
(1) using the drawing method to do the dynamic balance of the centrifugal fan, the method is simple and the price of the instrument is low. The vibration meter mentioned in this paper is GZ-4B type pocket vibration meter, the price is only about 900 yuan;
(2) the method of measured data for the fan during normal operation of the data, the most close to the working conditions of wind machine, than the general dynamic balancing machine (speed is far lower than the normal speed of the fan is generally 300 ~ 500r/min) high accuracy, with great popularization value in general industrial enterprises; the author has used test the type of comparative mapping method results and dynamic balancing instrument is introduced in this paper, the error is less than 2%;
(3) the method does not need to remove the impeller in the fan working site can save a lot of manpower and downtime; master, do a dynamic balance only around 1H, on site after repair for impeller balance especially, the replacement of the new impeller rotor balance and other inspection standard;
(4) the method is only suitable for centrifugal fans, and is not suitable for axial fans and volumetric fans.