Question regarding the allowable value for radial misalignment in diaphragm couplings
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As the title suggests, I would like to ask about the allowable value for radial misalignment in diaphragm couplings. Many manufacturers’ product manuals do not specify this value, and it is not provided either in GB9147. However, some manufacturers specify 0.04 or 0.02 mm (depending on the journal). I would like to ask everyone for their help; please, experts, give me some insights!
Do you mean coupling manufacturers when you talk about manufacturers?
It’s better to simply adjust according to the deviation of the rigidly connected coupling. It can be found in the Mechanical Design Handbook.
It is related to the rotation speed; at high speeds, it is 0.02
It is mentioned in SH/T3538
Yes, some coupling manufacturers provide radial misalignment specifications, while others do not.
Larger manufacturers will provide it, while smaller ones usually don’t have much of anything
For diaphragm couplings, it depends on whether it has a single diaphragm or a double diaphragm with an intermediate connecting element; for those with a single diaphragm, the value is 0.04, while for those with a double diaphragm, a difference of up to 0.5 mm is usually not a problem. The above applies to ordinary centrifugal pumps with a speed of 3,000 revolutions or less. If it is a multi-stage pump or one with a high speed, 0.04 is still required.
According to the instructions provided by membrane coupling manufacturers, for dual-membrane couplings, the value should be within 0.08 after 3,000 revolutions; for high-speed applications, this value should be within 0.04. For single-membrane couplings, this value should be one level higher
The misalignment angle, axis spacing, and radial misalignment are the three parameters of a right triangle; the misalignment angle corresponds to the radial misalignment. Given the axis spacing and angular misalignment, the radial misalignment can be calculated using trigonometric functions