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Hydrostatic Test

Hydrostatic test, widely used in daily life, hydraulic flaw detection, small valves, pressure vessels, pressure and burst test of various metal and non-metallic pipes; hydraulic pressure strength and sealing performance test of various petroleum tools; pressure instruments Instrument pressure detection and calibration; pressure and blast test of fire fighting equipment such as fire hose and fire extinguisher.

Common problems of hydrostatic test

Q:What are the conditions of the hydrostatic test? How to carry out hydraulic pressure test and hydraulic pressure test qualification standard?

1. Purpose of water pressure test of coal-fired steam boiler

Boiler pressure-bearing components must be tested for water pressure after overhaul, in order to make a thorough and meticulous inspection under cold conditions to check the tightness and strength of the pressure-bearing components.
During the water pressure test, the pressure-bearing system is filled with high-pressure water. Because the compressibility of the water is very small, the pressure can be transmitted to all parts evenly. If there are small pores on the pressure-bearing parts, or the welds, flanges, valves, hand holes, plugs, etc. are not tight, water will leak out; or a weak part of the pressure-bearing parts cannot withstand high pressure, it will occur Permanent deformation to rupture, so that the location of the defect of the pressure-bearing component can be checked according to the leakage, deformation and damage of the hydraulic test, and processed and eliminated in time.

2. Types and qualification standards of hydraulic test

There are two types of hydraulic tests, one is the hydraulic test with the test pressure at the working pressure: the other is the overpressure hydraulic test with the test pressure at 1.25 times the working pressure. After the boiler is overhauled, the working pressure and water pressure test should be done. The overpressure test will cause additional stress on the boiler and affect the life of the boiler. Therefore, it is only carried out under the following conditions:

a. The boiler in operation shall be carried out once every six years.

b. When a newly installed or relocated boiler is put into operation.

c. Boilers that have been out of service for more than one year will resume operation.

d. After the boiler is reformed, the pressure components have undergone major repairs or replacements, such as when the number of water-wall replacement tubes is more than 50%; when the superheater, reheater, economizer and other components are replaced in groups: the steam drum has undergone major repairs Time.

3. The eligibility criteria for hydrostatic testing are:

a. Under the test pressure, when the pressure drop in the boiler does not exceed 98 kPa/min;

b. The metal wall and welding seam of the pressure element are free of any traces of water beads and water mist, and there is no water leakage at the bulge;

c. There are no obvious residual deformation and abnormal conditions of the pressure-bearing parts.

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