Core Tip: Natural gas flow meters are rotor-type volumetric flow meters, also known as Roots flowmeters. Its existence has been over 100 years old. Its structural features are: in the flow meter housing there is a metering chamber. The metering chamber has a pair of natural gas that can be tangentially rotated (thereby being named natural gas flow meter). Natural gas flow meters can be used to accurately measure the flow of various cleaning liquids, especially for oil metering and gas metering. It has a high measurement accuracy, up to 0.1-0.5; no straight pipe requirements, a large range of advantages. But its shortcomings are also obvious: the structure is complex, bulky, bulky, inconvenient handling, not suitable for the measurement of high-temperature medium, large vibration and noise during operation, and large pressure loss. Used Picanol Air Jet Loom,220cm Air Jet Textile Machine,Used Picanol Omini Plus Air Jet Textile Loom Hicas Textiles Machinery Co., Ltd. , http://www.qdrapierloom.com
A pair of transmission gears are coaxially mounted on the outer surface of the flow meter housing with the two natural gases, and they mesh with each other so that the two natural gas can be linked with each other. The working principle is that the pressure difference between the two ends of the flowmeter causes the measuring element (two natural gas) to rotate, continuously divide the fluid into a single volume portion, and measure the total volume of the fluid using the drive gear and the counting indicator mechanism, and The standard flow rate is calculated by real-time pressure and temperature compensation. figure 1 
ABG Instrument Group has two kinds of natural gas and coke oven gas sources. The natural gas flowmeter has been used for more than ten years. From the upstream gas source plant to the downstream industrial and commercial users, the caliber has applications ranging from 25mm up to 400mm, especially for some non-continuous gas or unstable gas usage (such as the catering industry, boilers. For those users with large fluctuations in gas volume, natural gas flow meters have a low initial flow rate and the advantages of a large range ratio play an important role. Combined with our company's actual use of natural gas flow meters in gas metering, talk about your experience:
In the flow meter installation, as far as possible using the top-down type of installation. This is because, using the top-down approach, the impurities contained in the fuel gas can be carried out through the natural gas and can be partially taken out of the metering chamber to reduce the adhesion on the metering chamber wall; if the left-right-out installation method is used, the impurities will be Will be deposited in the metering chamber wall, can not be discharged in time, easily lead to gas stuck. This point is particularly important in the measurement of coke oven gas.
In normal use, the common causes are as follows:
1 The most common fault is that the gas does not pass through the flowmeter. The counters do not count the following reasons:
(1) The filter and the filter cover are clogged so that the gas cannot pass through the flow meter. This phenomenon often occurs on coal gas with relatively dirty gas. Especially in the winter, impurities such as dust, naphthalene, tar, and moisture contained in the gas easily adhere to the filter and the filter screen, causing blockage. I once had to clean up the filter completely three times a week in the winter. Whether the filter is clogged or not can be judged by comparing the pressure difference between the front and rear ends of the filter. If the pressure difference of the filter is large, the filter clogging is severe, and the filter core should be cleaned or replaced in time.
(2) Foreign objects (such as welding slag, sand, rust, grease, etc.) enter the metering room, causing the natural gas to jam. This phenomenon often happens when the flowmeter is put into use immediately after it is installed. As the pipeline is not cleaned, foreign matter enters the measurement chamber, causing the natural gas to get stuck. At this time, the flowmeter needs to be disassembled, natural gas is pumped out, the measuring chamber is cleaned, and the surface of the natural gas is repaired with burrs caused by foreign matter.
(3) Bearing wear, resulting in sinking of natural gas shafts. Flowmeter bearings generally use rolling bearings, in the early stages of wear, the flow rate of the flowmeter will increase, and the noise during operation will increase, which will produce a metallic sound that the rotor and the measuring chamber rub against each other; the wear of the bearing will be serious and it will cause the natural gas to die. Gas cannot pass through the flow meter. The cause of bearing wear is mainly due to poor lubrication, long-term operation of the bearing in the absence of oil, and shortened service life; or due to impurities in the gas attached to the bearing, causing the bearing ball to be damaged by grinding. This kind of failure is most common in the measurement of coke oven gas, especially in the winter, impurities such as tar and naphthalene in the gas are more likely to adhere to the metering chamber, natural gas surface, and bearings, accelerating bearing wear. In order to prolong the working life of the bearing, it is necessary to pay attention to the usual maintenance work: timely filling of the lubricant, timely cleaning of the filter, and regular replacement of the lubricant, to ensure that the meter works in a lubricated state.
2 The normal gas supply is normal, and the natural gas rotor works normally, but the counter is not working properly. If the counter counts are not continuous, “jump†or “card wheel†phenomenon occurs, and even the count does not occur. At this time, check whether the gears of the counter are worn or detached, whether the transmission shaft is deformed, whether the bracket of the counter is damaged, and whether the magnetic steel of the magnetic coupling is loosened and detached. For the damage of the counter part, replace the new counter; for the magnetic coupling of the magnetic coupling, it is necessary to pay special attention to the loss of magnetic steel may be adsorbed on other parts, causing damage to other parts, and even damage the seal , causing a safety accident. Our company has such an example. After the magnetic steel is detached, it adheres to the surface of the magnetic coupling and rubs against the sealing baffle. When it is found, the sealing baffle will be thoroughly polished. If it is not discovered in time, the consequences will be unimaginable.
3 Natural gas flowmeters equipped with intelligent flow totalizers and natural gas flowmeters equipped with intelligent flow totalizers are sometimes installed. The accumulative device sometimes shows that the display screen is not displayed or data (such as pressure, temperature, flow, etc.) are not displayed. Normally, this will cause the flow totalizer to not accumulate accurately. For the display does not show, the main consideration is to check whether the flow integrator battery is dead. For the display data is not normal, first of all to check whether there is strong electric field, strong magnetic field interference; if not, check the corresponding sensor wiring whether there is a virtual connection, off, open welding phenomenon; if not, you should consider the sensor failure. Find the cause of the failure, do the appropriate treatment to resolve the fault.
4 There is leakage in the flowmeter sealing part. The phenomenon of leakage in the seal part of the flowmeter, such as oil leakage and air leakage in the sealed parts such as the oil injection hole and oil window, will cause a huge potential safety hazard. This is mostly due to the aging failure of the seal ring and the seal must be replaced.
The above is the fault phenomena and reasons that often occur during the operation of natural gas flowmeters. To ensure the long-term stable operation of the flowmeter, we must pay attention to the daily maintenance work. We must make more inspections, observe carefully, and make records. We must maintain the ground, add oil and clean the filter in time, and add the flowmeter in winter. Install auxiliary heat devices and keep warm, keep the flowmeter and the corresponding temperature of the filter; do not let the flowmeter run over a long period of time; be sure to deal with minor faults in a timely manner, do not let the flowmeter with "disease" work, Avoid more serious consequences. In short, as long as the daily maintenance work is done well, the natural gas flow meter is an accurate and stable measuring instrument.