1. The static balance is carried out on one modified surface of the rotor to detect the balance, and the remaining unbalance after the correction is to ensure that the rotor is within the allowable range of unbalance in the static state, and the static balance is also known as the single-sided balance.

2, the dynamic balance is in the rotor on the two modified surface together to detect the balance, the balance of the remaining unbalance, to ensure that the rotor in the rotation is in the allowable unbalance requirements, the dynamic balance is called the two-sided balance.

3. Selection and confirmation of rotor balance

How to choose the balance method of rotor is an important problem.Its selection has such a standard: if the rotor balance is satisfied after the use of the need for conditions, can do static balance, do not do dynamic balance, can do dynamic balance, do not do static and dynamic balance.The reason is very simple, the static balance is easier to do than the dynamic balance, the dynamic balance is more accurate than the static and dynamic balance, save labor, labor and cost.So how to confirm the type of rotor balance?

The following elements and bases must be identified:

(1) the geometric shape and size of the rotor, especially the ratio between the diameter of the rotor (D) and the spacing between the two positive faces of the rotor (b), as well as the supporting distance of the rotor.

(2) working speed of the rotor.

(3) relevant technical standards for rotor balancing technology requirements, such as GB3215, API610 8th edition, GB9239 and ISO1940, etc.

4. The rotor is used for static equilibrium condition

In GB9239-88 balance in the specification, standard of rigid rotor do static balance is defined as: "if the disc rotor support distance is big enough and rotating disc position when the axial shaking, small, and can be ignored accidentally imbalance (dynamic balancing), the school with a positive measure not balance the balance of single (static), to be sure to know whether these standards to meet the actual rotor.After balancing some kinds of rotors in large number on one plane, the maximum residual couple unbalance quantity can be obtained and divided by the support spacing.If be below the most adverse condition this one value does not exceed allow to use the half that leaves unbalanced quantity, criterion choose one side (static) balance enough?Quot;From this definition, it is not difficult to see that the standard key for a rotor to do only one side (static) balance has three aspects: 1.1 is the rotor in the balance machine to do the balance of the support distance to be large;Another one is that the end face jitter of the correction surface is extremely small when the rotor rotates.

Explain the above three standards:

(1) what is a disc-shaped rotor is confirmed by the ratio of the diameter D of the rotor to the pitch size b between the two school facades of the rotor.In the API610 eighth edition standard, when D/b < 6, the rotor only needs to be balanced on one side.D/b 6 can be used as the rotor is not disk rotor standard requirements, but can not be absolute, because the rotor to do what kind of balance should also consider the rotor speed.

(2) the support distance shall be large without specific parameter requirements, but the support distance shall be deemed to be large if the ratio of the positive pitch b to the rotor alignment is greater than 5.

(3) axial vibration of the rotor

The key point is the end face jitter of the correction surface when the rotor rotates. Since any rotor has to undergo fine machining for the balance test, the behavioral tolerance between the hole of the rotor and the front of the alignment has been ensured after the machining, and the end face jitter is very small.According to the standard for single (static) balance of the rotor mentioned above, and in combination with the standard specification for related pumps (such as GB3215 and API610 eighth edition), the standard for status-only balance of the rotor is as follows:

(1) for the rotor of single-stage pump and two-stage pump, when the working speed is less than 1800 rotations/min, only the static balance can be performed regardless of D/b < 6 or D/b 6.But if the regulation does when moving balance, must make sure D/b < 6, do static balance only otherwise.

(2) for the rotor of single-stage pump and two-stage pump, if the working speed is 1800 rotations/min, if D/b 6, only the static balance can be done.But the remaining unbalance should be equal to or less than 1/2 of the allowable unbalance.If the regulation makes move balance, need to see 2 correct the balance of the face to be able to separate on balancing machine, if cent cannot leave, do static balance only.

(3) for some open wind wheel rotor, if can not maintain the support on both sides, only static balance can be done.Because the two sides can not support, it is necessary to carry out cantilever, so in the balance machine to do dynamic balance is very dangerous, only in the platform to carry out one side (static) balance.

5. Conditions for dynamic balance of the rotor

In GB9239 specification requirements: "where the rigid rotor if it can not meet the requirements of the disc rotor static balance, it is necessary to carry out 2 planes to balance, that is, dynamic balance.The standard of rotor for static balance only is as follows (balance static G0.4 is the highest precision, and G6.3 or G2.5 is selected for the dynamic balance static of the pump rotor under normal conditions) :

(1) for the rotor of single-stage pump and two-stage pump, when the working speed is 1800 rotations/min, as long as D/b < 6, the dynamic balance should be done.

(2) for the multi-stage pump and the rotor (3 or more than 3 stages), regardless of the working speed, should do the group of rotor dynamic balance.