To ensure the measurement accuracy of the electromagnetic flowmeter, proper installation is very important.
The transmitter should be installed in a dry and ventilated place indoors. Avoid installation in places where the ambient temperature is too high, should not be subject to strong vibration, try to avoid equipment with strong magnetic fields, such as large motors, transformers, etc. Avoid installation in corrosive gases. The installation location is easy to overhaul. This is the environmental condition to ensure the normal operation of the transmitter.
In order to ensure that the measuring tube of the transmitter is filled with the measured medium, the stacker is preferably installed vertically, and the flow direction is from bottom to top. Especially for liquid-solid two-phase flow, it must be installed vertically. If the site is only allowed to be installed horizontally, it must be ensured that the two electrodes are at the same level.
The transmitter should be equipped with valves and bypass at both ends.
The millivolt AC potential measured by the electrode of the electromagnetic flow transmitter is based on the liquid potential in the transmitter. In order to stabilize the liquid potential and maintain the potential of the transmitter and fluid to ensure stable measurement, the transmitter shell and the metal tube should have good grounding at both ends, and the converter housing should also be grounded. The grounding resistance should not be greater than 10 and cannot be shared with the grounding wire of other electrical equipment. If the transmitter housing is not guaranteed to be in good contact with the metal pipe, connect them with metal wires. Re-reliable grounding.
In order to avoid interference signals, the signal between the transmitter and the converter must be transmitted with shielded wires. It is not allowed to place the signal cable and power cable in parallel in the same cable. The length of the signal cable should generally not exceed 30 m.
Converter installation site should avoid AC and DC strong magnetic field and vibration, ambient temperature is -20 to 50 ° C, does not contain corrosive gases, relative humidity is not more than 80%.
In order to avoid the influence of the flow rate on the relative measurement, the flow regulating valve should be placed downstream of the transmitter. For small-caliber transmitters, since the distance from the center of the electrode to the inlet end of the flowmeter is equivalent to several times the length of the diameter D, the upstream straight pipe may not be specified. However, for a flowmeter with a large diameter, generally there should be a straight pipe section of 5D or more in the upstream, and the downstream pipe section is generally not required.
Third, gas turbine flowmeter daily inspection
1. Look at the display: Observe the total amount, instantaneous, temperature, pressure, and battery power. If the abnormality is reported in time.
2. Listen to the running sound of the flowmeter. (Method) The flowmeter should have no noise when it is running normally. If there is a large abnormal noise, it can be judged as damage to the movement of the movement (for example). It needs to be reported and processed in time.
3, data comparison, the output of the first 3 to 5 days before the statistics, if there is no major change, the flowmeter runs normally, such as the successive decrement phenomenon, the gas turbine flowmeter impeller (shaft, shaft core), filtration There is a problem with the device. Need to be reported in time for processing
4, gas turbine flowmeter filling lubricant
(1) Instrument refueling is an important part of the daily maintenance work of the instrument. Lubricating oil is mainly for instrument bearing; lubricating oil can protect the instrument bearing, reduce friction, reduce wear and prolong the operation cycle of the instrument;
(2) Regularly adding lubricating oil can effectively reduce the maintenance rate of the instrument and reduce the maintenance cost;
(3) Ensure the measurement accuracy of the flowmeter. "Measuring is counting money." why would you said this? The management of production and operation accounting, energy saving, cost accounting, etc. is an important production link of enterprise management. If the measurement is not in place, it will affect the economic efficiency and reputation of the enterprise. Therefore, the daily maintenance of the instrument is very important.
Selection of measurement types for special industrial and commercial users
At present, there are some special users in the supply of industrial and commercial users. On the one hand, the gas points are more dispersed, and the amount of gas used in a single combustion device is small (generally 2 to 9 m3/h); on the other hand, the total amount of gas used is Very large, there are many problems with the accurate measurement of the natural gas supply of such users. This type of industrial and commercial users have multiple fuel appliances with different gas consumption. Different gas consumption at different time periods brings certain difficulties to the accurate measurement of natural gas. Under the condition of satisfying the maximum gas consumption, it cannot be measured under the condition of small flow. The problem.
1. Case 1: A large shopping and entertainment mall
The mall has 22 gas points distributed on the second, fourth and fifth floors. In order to ensure the accuracy of natural gas measurement, the gas supply system has a master meter (turbine flow meter Q650) and 22 sets of compensation functions. As a metering table, the flow meter usually has a gas consumption of about 400m3/d and a holiday of about 800m3/d. It is found through the data collection that the total number of meters and sub-meters is about 17m3 per day; in the initial 54d. The cumulative gas consumption of the master meter and the minute meter differs by 11511.80 m3.