做为差压式流量计的一种，和孔板流量计一样也用于非常长的的使用历史。 As a type of differential pressure flowmeter, V-cone flowmeter is also used for very long use history like orifice flowmeter. The production of V-cone flowmeters makes up for the lack of orifice plate flowmeters in some cases. For corrosive occasions.
The design principle of the V-cone flowmeter is no longer that of an orifice plate, and the fluid is forced to contract near the centerline of the pipe, nor is it a sudden change in direction of the fluid due to a barrier. Instead, the inner cone-type throttling device is used to gradually shrink the fluid toward the inner wall of the tube, so that the V-shaped inner cone throttling device has a series of unique advantages. However, it also has disadvantages. In order to obtain higher accuracy, it must be calibrated by real flow, unlike the orifice plate flow meter, which only needs to be calculated.
The advantages of V-cone flowmeters are:
The throttling of this throttling device is gradually produced, so it does not have high requirements on the flow of fluid, and it has the function of automatically correcting the velocity distribution of the distorted stream, it has a rectifying effect, and it can largely eliminate vortex II. Secondary flow, which makes this throttling device greatly reduce the requirements of the front and back straight pipe sections. In addition, this throttling device can only generate high-frequency and low-amplitude surge (small eddy current) downstream, so the differential pressure signal measured by the differential pressure transmitter is a low-noise signal. Pressures with resolution better than 25PA can be measured. In this way, only a differential pressure transmitter can be used to obtain a wide range ratio (the range ratio can be greater than 15: 1) and good repeatability (better than 0.1%). 在很多方面弥补了孔板流量计的不足。 Dongxiang Instrument V cone flowmeter is designed and manufactured on the basis of the orifice plate flowmeter. It has the technical basis of the orifice plate flowmeter manufacture. The designed and manufactured V cone flowmeter makes up for the orifice plate flowmeter in many aspects. insufficient. More professionally continue to develop the differential pressure flowmeter technology to ensure the market position of traditional flowmeters, and to help customers save costs very well from the customer's standpoint.
The main sources of measurement errors of V-cone flowmeters are caused by improper installation, untimely maintenance, or changes in process system operating parameters. Today I will summarize the faulty operation of the V-cone flowmeter.
1. The first is irregular installation
There are several main reasons for the irregular installation of V-cone flowmeters in the field: the lack of straight pipe sections before and after the process pipeline causes fluid instability and affects the measurement accuracy; there is a problem with the installation direction. Of course, this problem will basically not occur. Unless it is caused by an error in the field installation; when measuring steam, the condensing device does not cool down completely and the installation height varies
2, followed by the misoperation of the secondary instrument
现场使用的时候，都要配备差压变送器才能正常使用，所以，差压变送器性能和安装的正确与否直接影响V锥流量计的整体精度。 When the V-cone flowmeter is used in the field, a differential pressure transmitter must be equipped for normal use. Therefore, the performance and installation of the differential pressure transmitter directly affect the overall accuracy of the V-cone flowmeter. The V-cone flowmeter still has successful operation experience in measuring mixed fluids, but it is necessary to pay attention to the corrosion protection of the differential pressure transmitter and periodically open the drain valve.
3, the final impulse tube is blocked or leaking
When measuring viscous and crystalline media, the pressure guiding tube and the shut-off valve are often blocked due to heat tracing and other reasons, which causes the differential pressure value input to the differential pressure transmitter to change, resulting in measurement errors. Elimination methods are to conduct inspections on time, clean the sewage or clean with a hand pressure pump. When measuring high-pressure or corrosive media, pressure leaks or joints often leak, causing pressure loss and differential pressure deviation. The solution is to conduct inspections on time and plug the loopholes. Through the above description, our on-site maintenance technicians can easily find the fault of the V-cone flowmeter and reduce the on-site economic loss.