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Why is the orifice flowmeter deformed?

Author:    Source:    Date: 2021-05-27 14:29:51
Orifice flowmeters often deform under working conditions, resulting in the inaccurate measurement of the instrument. The deformed orifice plate is often an orifice flowmeter with a larger diameter, and the temperature of the measuring medium is higher, such as superheated steam, an annular pressure throttling device with a relatively thin orifice plate thickness.
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Take the expansion coefficient as 5≤amp≤multiply and measure as the expansion coefficient material, so the line of steel 16≤amp≤10≤6℃~(-1) room is general, 10≤6℃~(-1)11≤amp≤10 ≤6℃~(-1), the hole is stainless steel, the plate is generally online but the carbon ring is poor, and the expansion coefficient of the material is 304. , The expansion part of the device plate used is corresponding to the expansion of the chamber orifice plate, and the inner diameter of the orifice is expanded at high temperature. The outer diameter of the ring is larger than the increase in the outer diameter of the ring fluid when it is put into contact. The increase in the chamber is actual. In between, it must be higher than the processing and the board is relatively in the room temperature room gap, so the hole expansion changes the size of the board. Our low room is manufactured enough "General ring geometry, the use of the plate they are ringed because it is significant. Therefore, The hole, and the temperature, but the temperature, manufacturing.

So, who is responsible for the deformation of the orifice flowmeter? Today, after on-site investigation and on-site analysis, the staff of Mingyu Automatic Control Equipment found clues related to it. One thing is certain, that is, the deformation of the orifice plate is caused by thermal expansion. The gap between the outer diameter of the orifice plate and the annular chamber disappears. When the orifice plate continues to expand, the orifice plate cannot move toward the outer diameter. Expansion, so under the action of the pressure difference on both sides of the orifice, the convex deformation of the outlet side occurs.

The first point is related to the weather. There is no air leakage in the throttle device, because the weather is cold and the northwest wind blows badly, causing water leakage at the junction of the positive and negative ring chambers.

Again, this is related to poor insulation of the throttle device. The throttling device has no water leakage and has good heat preservation performance.

The third type is related to the leakage at the joints of the positive and negative annular chambers. The tightening bolts cannot eliminate the leakage. Therefore, the throttle valve device was disassembled and the sealing gasket was replaced. It was found that the orifice plate was deformed.

In the design and calculation of the throttle device, the gap between the outer diameter of the orifice plate and the annular chamber is large enough, and it can be assumed that the temperature of the orifice plate and the annular chamber are the same, but in fact it is impossible to be the same. The orifice plate is surrounded by an annular cavity, and there is a high temperature fluid to provide heat, the temperature is high, and the temperature is completely expanded. However, the inner ring of the ring is in contact with the fluid, the outer ring is in contact with the atmosphere, coupled with poor insulation, the weather is extremely cold; the northwest wind is blowing; and other factors, the temperature drops very low, resulting in insufficient retention gaps, resulting in deformation of the orifice plate .

In addition, the deformation of the orifice is closely related to the leakage of the positive and negative annular chambers. If it is not caused by the damage of the sealing gasket, it is because the gap between the positive and negative ring cavities increases after the orifice plate is deformed, and the gap between the sealing gasket and the ring cavity causes leakage.

Guanghua Rd, Qingyang Dist, Chengdu, Sichuan Province, China 备案号:蜀ICP备13021392号-1