CN115406494A - Novel method and structure with sealing structure capable of being connected in series in closed pipeline for weighing liquid mass flow - Google Patents

Abstract

An instrument that adopts the method of direct weighing, has a closed structure, can be connected in series in a closed infusion pipeline, and directly measures the mass flow rate of the liquid flowing through the pipeline. It has two sealed containers with dynamic gas-liquid isolation inside. The device divides the inner cavity of the container into two parts, the upper part is filled with gas, and the lower part is filled with the liquid to be measured; the upper part of the gas is connected through the trachea, and cooperates with the measurement process for two-way flow; the lower parts of the two containers are respectively connected to the reversing valve through the lower standpipe, Under the control of the reversing valve, one of the two containers is filled with liquid, while the other is drained (that is, the weight is reduced). This process is carried out continuously and alternately. The weight is gradually reduced) to carry out continuous weighing measurement, so as to complete the purpose of mass flow measurement. This instrument uses a simple weighing method and a fairly mature weighing sensor, combined with a special structural design and data processing system, to perfectly realize the accurate measurement of liquid mass flow (including instantaneous and cumulative mass flow) in a closed pipeline.

Description

A weighing type with a sealed structure that can be connected in series in a closed pipeline to measure the quality of liquids The new method of flow and its structure

technical field

The invention belongs to the field of general testing instruments, relates to the measurement of liquid mass flow, and belongs to the category of measurement and testing.

Background technique

In today's social production and life, the measurement of liquid substances is mostly marked by volume and measured by volume flowmeter. However, there are still many industries that use the method of measuring volume is not rigorous enough, and only the way of marking the quality is the most reasonable. For this reason, after years of hard work, flow measurement workers have developed a variety of flowmeters or combined measurement systems for measuring quality, the most representative of which is the Coriolis force mass flowmeter, because of its profound measurement principle and special structure, The product has been launched for decades, but there are still some problems that have not been well resolved, such as high requirements for the installation environment of the instrument, complex structure, difficult maintenance, zero drift, hidden dangers of fatigue fracture of the detection tube, high price, etc., making the product still in a state of imperfection and Continuous improvement.

Contents of the invention

This patent proposes a weighing method and a supporting weighing structure for the liquid transported through a closed pipeline to achieve the purpose of directly measuring the mass flow rate. Compared with the existing mass flowmeter, the method is clear, the structure is simple, the installation is convenient (directly connected in series with the pipeline for conveying liquid), and the closed structure is almost suitable for mass flow measurement of various easy-flowing liquids. (1)

Detailed ways

The weighing method is adopted, and the electromechanical integrated structure is adopted. The real object of this instrument includes a mass flow meter (hereinafter referred to as the flow meter) and a secondary instrument. and continuous measurement. See "Schematic Diagram of Flow Meter Structure" for the structure.

Description of the drawings: Figure 1 shows the schematic diagram of the structure of the mass flowmeter in this instrument;

In the figure: (1) load cell; (2) upper leaf spring; (3) dynamic liquid-gas isolation device;

(4) Air chamber; (5) Sealed container; (6) Liquid chamber; (7) Lower leaf spring;

(8) Infusion pipeline; (9) Lower riser; (10) Reversing valve;

(11) connecting trachea; (12) hanging wire;

(2) Structural characteristics of the flowmeter (combined with the "Schematic Diagram of Flowmeter Structure")

Two juxtaposed airtight containers 5 (referred to as the right container and the left container respectively) are elastically consolidated with the base body by the leaf springs 2, 7 respectively, and the container is hung by the load cell 1 fixed on the base body through the hanging wire 12 (or from the hold below). The container is equipped with a dynamic liquid-gas isolation device 3, which divides the container into two parts, the upper part is called the air chamber 4, and the lower part is called the liquid chamber 6. The gas chambers of the two containers are communicated with the connecting air pipe 11, and the liquid chamber is connected with the reversing valve 10 by the lower standpipe 9. The right end of the reversing valve has an inlet A and the left end has an outlet B and the infusion pipe 8 (also called right pipe and left pipe respectively). in series.

Now combine the working process of this instrument for elaboration:

After the flowmeter is connected in series to the pipeline, its working process enters the following stages:

The first stage:

After the flowmeter is connected in series with the infusion pipeline 8, the lower parts (liquid chambers) of the two containers are gradually filled with the measured liquid, and the liquid level gradually rises; the gas in the upper gas chamber is compressed by the dynamic liquid-gas isolation device until it is in contact with the liquid chamber Until the liquid pressure (that is, the pressure in the infusion pipeline 8) reaches a balanced state, the liquid level does not rise any more, and the liquid level is adjusted to the middle position of the container.

Phase II Measurement phase:

When it is necessary to measure the mass flow rate of the liquid in the infusion pipeline, start the measurement function of the instrument, and the output port B of the reversing valve 10 is automatically connected to the lower standpipe 9 of the right container (called the lower right pipe), and the liquid in the right container 5 passes through B flows out, the liquid level of the right container gradually decreases, and the weight of the right container gradually decreases; this process is converted into a voltage signal by the load cell 1 (this process is called right container weighing), and is sent to the secondary instrument for data processing, and the display Mass flow rate; while the liquid is continuously flowing out from the right container, the input port A of the reversing valve 10 and the lower vertical pipe of the left container (called the lower left pipe) are also in a connected state, and the liquid in the right infusion pipe 8 flows into the left container. liquid chamber, and the gas in the air chamber of the left container flows into the air chamber of the right container through the communicating gas pipe 11. The liquid in the left container continues to increase, and the liquid level in the left container rises gradually; when the liquid level in the right container drops to a certain level (shown by the dotted line), the reversing valve 10 is quickly switched to make the high-level liquid in the left container (shown by the dotted line) ) began to flow out from the lower left pipe through port B; the liquid level of the left container gradually decreased, and the weight of the left container gradually decreased. Secondary instrument data processing, display mass flow.

In a word, the above-mentioned process is carried out continuously, and the two containers are repeatedly weighed successively, thereby realizing the continuous mass flow measurement of the liquid flowing through the pipeline.

(3) Advantages of this instrument

1) The installation and debugging are simple and can be calibrated in due course;

2) It has a wide range of applications and can be used for mass flow measurement of liquids with different properties, including volatile liquids and liquids harmful to the human body;

3) High measurement accuracy, stable and reliable performance; this instrument adopts the method of direct weighing, organically combines the mature weighing sensor and the special structure of the flow meter, and connects it in series in the infusion pipeline, and uses it as a high-precision online instrument;

4) Simple structure, high cost performance, easy to use, easy to promote;

(4) Further description of the structural features of this mass flowmeter

Based on the weighing method of this mass flowmeter, the realization of its function is inseparable from the characteristics of the container and its internal structure.

1) The shells of the left and right containers have reliable sealing performance, and are connected in series with the closed infusion pipeline to be used as an online instrument.

2) A dynamic liquid-gas separation device is installed inside the container, which divides the container into two parts; the upper part is called the air chamber (inflated body); the lower part is called the liquid chamber (filled with the liquid to be measured), to prevent gas-liquid contact.

3) The container is connected to the base body through two leaf springs up and down, which only allow the container to move up and down.

4) For the two containers of this flowmeter, the upper air chambers are connected by air pipes, and the gas in the air chambers is isolated from the atmosphere. The lower liquid chambers are respectively connected with the reversing valves through respective lower risers.

5) Each container is lifted from the upper part (or lifted from the lower part) by the load cell fixed to the base for weighing measurement.

6) There is a liquid conversion channel inside the reversing valve, and there are four ports on the outside, two of which are respectively connected to the lower risers of the two containers, and the other two ports are the inlet and outlet ports A and B connected in series with the infusion pipeline 8 . Under the control of the secondary instrument signal, the channel in the valve is quickly switched, and the opposite filling and discharging process of the lower parts of the two containers can be instantly changed, so that the liquid in the infusion pipeline 8 flows through the flow meter and is continuously weighed by the sensor on the upper part of the two containers. Weighing, the weighing data is transmitted to the secondary instrument for data processing, so as to complete uninterrupted mass flow measurement.

Claims (6)

1. An electromechanical combination liquid mass flow measuring instrument, comprising two parallel containers 5 , two weighing sensors 1 , and one liquid reversing valve 10 . 2. The flowmeter according to claim (1), characterized in that the two containers are fixed by two parallel leaf springs 2 and 7 above and below, allowing only vertical displacement. 3. The flowmeter according to claim (1), each container is lifted by its upper load cell (or lifted from the lower part), when the liquid in one container flows out (while the other container flows into liquid), the reduction in the total weight of the container is measured. 4. The flow meter according to claim (1), characterized in that each container has a dynamic gas-liquid isolation device, which divides the container into upper and lower parts; the upper air chamber 4 is filled with compressed gas, and the lower liquid chamber 6 is filled with the liquid to be measured. 5. The flow meter according to claim (1), characterized in that the upper parts of the two containers are communicated by the connecting gas pipe 11 to form a gas transfer channel. 6. The flow meter according to claim (1), characterized in that there is a liquid reversing valve 10, which switches the liquid path under the control of the secondary instrument, so that the process of entering and discharging the liquid in the two containers (gas in the upper part of the container) Corresponding transfer) can be carried out continuously, so that the liquid in the closed infusion pipeline can be directly weighed to realize the continuous on-line measurement of the liquid mass flow rate.

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