CN202329695U - Probe structure of vortex shedding flowmeter - Google Patents

Abstract

The utility model provides a probe structure of a vortex flowmeter, which includes a first probe and a second probe, the first probe and the second probe respectively include a shell and a center column fixed in the shell, each Two piezoelectric ceramic sheets with positive and negative phases are respectively bonded to the core column by conductive glue, and the piezoelectric ceramic sheet is wrapped with a filling layer, and each core column is connected with two external signal lines; the first probe The housing of the second probe is welded and fixed, and there is a distance between the center stem of the first probe and the center stem of the second probe. The utility model comprises a first probe and a second probe. The first probe is used to detect flow signals, and the second probe is used to detect interference signals such as pipeline mechanical vibration. The parameters of the interference signals detected by the second probe are used as reference samples to filter 1. Shielding the interference signal doped in the flow signal of the first probe, so as to achieve the purpose of purifying the flow signal detected by the first probe.

Description

Probe structure of vortex flowmeter

technical field

The utility model relates to a vortex flowmeter, in particular to a probe structure of the vortex flowmeter.

Background technique

The vortex flowmeter is a flow meter that detects fluid oscillation signals based on the "Karman vortex street" principle. When a cylinder with a bluff cross section is inserted into a flowing fluid, two columns of vortices are generated in a staggered arrangement on both sides of the rear of the cylinder. The separation frequency f of the vortex is proportional to the column side flow velocity V and inversely proportional to the column width d. Fluid velocity and instantaneous flow can be measured by measuring the separation frequency of the vortex. Therefore, as a speed flow meter, the vortex flowmeter is one of the main flow meter products in the world at present, and is widely used in petroleum, chemical, metallurgical and other industrial sectors, municipal construction and environmental protection projects.

The measurement of the vortex flowmeter requires the clearer the effective signal collected, the better, which requires that the sensitivity of the vortex probe receiving the signal is relatively higher, the better. However, due to the higher sensitivity of the vortex street probe, the received interference signal is relatively more obvious. In the environment with a lot of interference, the vortex flowmeter cannot effectively identify the effective flow signal, resulting in excessive measurement errors and frequent failures in the operation of the flowmeter. faults etc.

The measurement of the flow signal of the vortex flowmeter is realized by the probe of the vortex flowmeter. Referring to Fig. 2, the probe structure of the existing vortex flowmeter includes a probe shell 3, and a central core column 4 fixed in the shell 3. The central core column 4 is made of a stainless steel bar, and the central core column 4 is passed through a conductive There are four positive and negative piezoelectric ceramic sheets bonded by glue, and the piezoelectric ceramic sheets are wrapped with a filling layer 5. The material of the filling layer 5 is cured epoxy resin or inorganic glue. Two external signal lines 6a, 6b is connected to the core column 4. When in use, the probe is installed in the tube body. When the vortex hits the sensing surface of the probe, the piezoelectric ceramic sheet produces a charge change and generates a flow signal. At the same time, the flow signal is mixed with interference signals. This kind of probe structure has the disadvantage of not being able to distinguish the flow signal from the interference signal, which leads to many field problems in the measurement of the vortex flowmeter. For example: there is no flow in the pipeline, but the vortex flowmeter shows a fixed flow value, which is actually the flow calculated by the interference signal; or the pipeline has a stable flow, but the flow rate displayed by the vortex flowmeter fluctuates greatly, which is a lot In some cases, the interference signal is too strong. The interference signals here are mainly manifested as 50Hz power frequency interference, motor operation interference, pipeline vibration, etc. Due to the existence of the above problems, ordinary vortex flowmeters cannot be used in working environments with complex working conditions, but are mostly used in working environments with weaker vibration and better site conditions.

Utility model content

The technical problem solved by the utility model is to provide a probe structure of a street flowmeter, which can distinguish flow signals and interference signals, thereby filtering and shielding the interference signals.

The technical scheme of the utility model is: a probe structure of a vortex flowmeter, which is characterized in that it includes a first probe and a second probe, and the first probe and the second probe respectively include a housing and are fixed on the housing. The core pillars in the body, each core pillar is respectively bonded with two piezoelectric ceramic sheets with positive and negative phases through conductive glue, the piezoelectric ceramic sheets are wrapped with a filling layer, and each central pillar is connected with two An external signal line; the shell of the first probe and the shell of the second probe are welded and fixed, and there is a distance between the central stem of the first probe and the central stem of the second probe.

The core column of the first probe and the core column of the second probe are made of stainless steel strips.

The material of each filling layer is cured epoxy resin or inorganic glue.

The central stem of the first probe and the central stem of the second probe are located on the same central axis.

The two external signal wires on the central stem of the first probe pass through the shell of the second probe.

The beneficial effects of the utility model are: the utility model now has two probes for the single probe of the prior art, that is, the first probe and the second probe, and the center stem of the first probe and the center stem on the center stem The piezoelectric ceramic sheet is separated from the center column of the second probe and the piezoelectric ceramic sheet on the center column respectively. The first probe is used to detect the flow signal, and the second probe is used to detect interference signals such as mechanical vibration of the pipeline. The parameters of the interference signal detected by the second probe are reference samples, which filter and shield the interference signal doped in the flow signal of the first probe, so as to achieve the purpose of purifying the flow signal detected by the first probe and make the vortex flowmeter in the pipeline In the case of strong vibration interference with a vibration intensity of up to 3g, the vortex flowmeter can still accurately detect the effective flow signal of the vortex, and achieve accurate measurement, reflecting high stability and super vibration resistance, so that the vortex flowmeter can In a more complex working environment, the field of use of the vortex flowmeter has been greatly expanded.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is a schematic structural diagram of the prior art.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described:

Referring to Fig. 1, a probe structure of a vortex flowmeter includes a first probe 1 and a second probe 2, and the first probe 1 includes a first housing 3 and a first central stem fixed in the first housing 3 4. The first central pillar 4 is bonded with two first piezoelectric ceramic sheets with positive and negative phases through conductive glue, the first piezoelectric ceramic sheet is wrapped with a first filling layer 5, and the first central pillar 4 is respectively Two first external signal wires 6a, 6b are connected, the material of the first core post 4 of the first probe is a stainless steel strip, and the material of the first filling layer 5 is cured epoxy resin, which can also be cured Inorganic glue. The second probe 2 includes a second housing 7 and a second central stem 8 fixed in the second housing 7, and the second central stem 8 is bonded with two pieces of second piezoelectric electrodes with positive and negative phases through conductive glue. A ceramic sheet, the second piezoelectric ceramic sheet is wrapped with a second filling layer 9, the second central stem 8 is connected with two second external signal lines 10a, 10b, and the material of the second central stem 8 of the second probe is For the stainless steel bar, the material of the second filling layer 9 is cured epoxy resin, or cured inorganic glue. Welding is fixed between the first housing 3 of the first probe and the second housing 7 of the second probe, and there is a gap between the first middle stem 4 of the first probe and the second middle stem 8 of the second probe. There is also a separation distance between the first piezoelectric ceramic sheet and the first filling layer 5 and the second piezoelectric ceramic sheet and the second filling layer 9 . The first central stem 4 of the first probe and the second central stem 8 of the second probe are located on the same central axis. The two first external signal wires 10a, 10b on the first central stem of the first probe pass through the second housing 7 of the second probe.

The working principle of the utility model is as follows:

The first probe is installed inside the pipe body to receive the impact of the vortex vortex, so as to measure the flow signal, and the second probe is installed outside the pipe body to measure the vibration of the pipe body and the interference signal generated when the motor is running. The parameter of the interference signal detected by the probe is a reference sample, and the interference signal doped in the flow signal of the first probe is filtered and shielded, so as to purify the flow signal detected by the first probe.

Claims (5)

1. the sonde configuration of a vortex shedding flow meter; It is characterized in that: comprise first probe and second probe; Said first probe and said second probe comprise housing respectively and are fixed on the middle stem stem in the housing; The piezoelectric ceramic piece of two alternate positive and negatives is arranged through conductive adhesive respectively on the stem stem in each, and said piezoelectric ceramic piece is wrapped with packed layer, and stem stem is connected with two outer signal lines respectively in each; Welding is fixed between the housing of the housing of first probe and second probe, and leaves spacing distance between the middle stem stem of the middle stem stem of first probe and second probe.

2. according to the sonde configuration of the described vortex shedding flow meter of claim 1, it is characterized in that: the material of the middle stem stem of the middle stem stem of first probe and second probe is stainless steel strip.

3. according to the sonde configuration of the described vortex shedding flow meter of claim 1, it is characterized in that: the material of each packed layer is epoxy resin or the inorganic glue of having solidified.

4. according to the sonde configuration of the described vortex shedding flow meter of claim 1, it is characterized in that: the middle stem stem of the middle stem stem of first probe and second probe is positioned on the same axis.

5. according to the sonde configuration of the described vortex shedding flow meter of claim 1, it is characterized in that: two outer signal lines on the middle stem stem of first probe pass from the housing of second probe.

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