measurement method to determine the selection instrument on performance requirements to consider are: the content of the instantaneous flow rate and total (
The cumulative flow)
, degrees, repeatability, linearity and flow range and scope of degree, the pressure loss, output signal characteristics and response time, etc.
Different objects have their respective measurement purposes, have different emphasis on its performance in the instrument.
For example, business accounting and storage requirements for degrees is higher;
Continuous measurement process control usually require only good reliability and repeatability, sometimes also requires a wide range of degrees, while also measuring degree of subsidiary;
Ratio of bulk production is hope to have good degrees.
1, measuring flow rate or the purpose of the object is used to measure the total there are two types, namely the measurement of flow and measuring the total.
Use place main pipe ratio of continuous production or process control measuring instantaneous flow rate;
Filling the container batch production and business accounting, storage and distribution and other places of use most as long as the total amount or complementary with traffic.
Two kinds of different functional requirements, and then choose some measuring methods have different emphases on instruments such as volumetric flowmeter, turbine flowmeter, with mechanical technology on measuring principle or pulse frequency output, directly get total amount, so has the height, is suitable for measuring the total.
Electromagnetic flowmeter, ultrasonic flowmeter, the throttle flowmeter instrument principle is deduced based on measurement of fluid flow on flow, fast response, suitable for process control, but also has the function of integrating link after the amount can be obtained.
Vortex street flowmeter has the most advantages, but its earthquake, anti-interference performance is poor, not suitable for process control and is suitable for measuring the total.
2, electromagnetic flowmeter measurement of whole degrees requirements?
In a particular flow, or within a flow range to use?
What the measurement range of the above?
The selected instrument degrees can maintain how long?
Easy to check again?
Whether or not to (
Online check instrument?
These issues must be carefully considered.
If not simply measuring the total, but the application in the fluid flow control system, the determination of instrument measuring of degrees to as required by the control degree of the whole system, because the whole system not only has the traffic detection error, also contains a signal transmission, control and operation error and various influence factors, such as operation link tend to have about 2% back to the poor, for measuring instrument to determine higher degrees (
Such as 0.
It is not reasonable and not economic.
In terms of flow meter itself, the detecting element (
And conversion/only degree should also be appropriate to determine between display instrument, such as without real velocity-equalizing tube flow calibration, wedge pipe, pipe bending arithmetic device error between 1% and 5%, choose high precision differential pressure gauge to match has no meaning.
Electromagnetic flowmeter flow meter specifications set by the grade is works in a wide flow rate range, if the conditions of use in a particular flow or flow range is very narrow, with turbine flowmeter metering of the oil distribution in, for example, only under the condition of the valve fully open, basic constant flow, or change only in a small scope, the use of measuring e. high degree comparable.
If you can in this special calibration measurement point, can improve the degree, for example from 0.
Level 5 to 0.
25 level or higher.
Used in business accounting, storage and transportation and material balance requirement is high, degree of persistence, should also be considered whether key factors such as easy to check again, and the possibility of online check.
In comparing the manufacturer of the instrument performance specification, pay attention to the error is guided with the percentage of error (
Measurement limit or range of percentage, commonly used % F.
, and relative error (
Measured values, the percentage of commonly used % R said)
Usually sample or specification only error %, and did not indicate the % F.
S or % R, often refers to % F.
S, because the flow meter instantaneous flow error % F.
S for many, this is not rigorous.
If can do % R, for its superior performance, must be indicated.
Also note that factory product manuals, degree is refers to the basic error using the environment at the scene, power, fluid will produce additional error conditions change.
Field use degrees shall be the basic error and affect the amount of additional error synthesis, such as large amount of influence, additional error could be far more than the basic error.
Guangdong Kaidi Energy Technology Co., Ltd. guarantees to providing quality products and services.
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