CN2121015U - On-line variable capacity luquid flowmeter - Google Patents

Abstract

The utility model discloses an on-line variable measuring range liquid flowmeter which is used for the measurement of the flow rate of liquid in a pipe, comprising a flow rate sensor, a pressure difference transmitter, and a secondary instrument, wherein, the flow rate sensor is an elbow pipe which is connected with a liquid channel; the inner pipe wall of the inner turning angle of the elbow pipe is provided with a wedge-shaped convex arris; the front and the back pipe walls of the convex arris are respectively provided with a pressure fetching hole; pressure difference generated between the two pressure fetching holes is used to display the flow rate in the pipe through calculating programs which are solidified in the pressure difference transmitter and the secondary instrument. The utility model has the advantages of wide measuring range for flow rate, good measuring accuracy, firmness, and durability.

Description

On-line variable capacity luquid flowmeter

The utility model relates to a kind of online changeable fluid liquid flowmeter that fluid flow is used in the pipeline that detects.

In having the industrial production facilities of line device, often to detect the flow in pipeline, to meet the needs of production, the detection method of not interrupting current previously, mostly be that a throttling device such as orifice plate is installed in pipeline, utilize current to flow through before and after the orifice plate pressure differential that is produced, come calculated flow rate, this method, because restricting element immobilizes, its range is subjected to certain limitation, both be worn easily, the fluid pressure loss is also very big; Recently, produce a kind of orifice valve, this valve can not interrupt current, promptly under online situation, change different orifice plates, to enlarge its sensing range, but this will prepare the polylith orifice plate, structure more complicated, cost height, when changing orifice plate, sometimes because orifice plate is stuck in pipeline, corrosion is changed very difficult, and still can not solve the big problem of fluid pressure loss, so can not satisfy request for utilization.

The purpose of this utility model is that a kind of improved online changeable fluid liquid flowmeter will be provided, and it is simple in structure, and is sturdy and durable, and cost is low, and is easy to use, because of its range can change, so the corresponding sensing range that enlarged has improved measuring accuracy.

The purpose of this utility model is achieved in that this online changeable fluid liquid flowmeter is the liquid that utilizes in flowing, in the pipeline of bending during constricted flow, under the effect of centrifugal force and restricting element, the flow difference, diverse location place at inner-walls of duct, the pressure that is born is also inequality, and following funtcional relationship is arranged between its flow and the two point pressure differences:

$Q=0.003999\·{\mathrm{KD}}^2\sqrt{\frac{\mathrm{\ΔP}}{\mathrm{\ρ}}}$ In the formula

Q: flow m ³/ h; K: coefficient of flow, demarcate by actual measurement;

D: bend pipe internal diameter mm; ρ: fluid density kg/m ³

Δ P: the pressure differential Pa between 2 pressure points; 0.003999: the conversion factor that unit conversion produces;

Change the different pressure taps on the tube wall, and compare its pressure differential, can record the flow in maximum magnitude flow range inequality, thus the corresponding measuring accuracy that improved.

According to above-mentioned principle, this liquid flowmeter is made of flow sensor, pressure difference transmitter and secondary instrument, flow sensor is made of the square bend pipe that two ends connect liquid line, on the inwall of inboard, bend pipe corner, be provided with the wedge shape fin, before and after fin,, be provided with and the extraneous hydraulic pressure pressure tappings that is connected and has valve along on the tube wall of bend pipe; The input end of pressure difference transmitter has two pipe interfaces, can be connected with the pressure pipeline of two various combinations, and the output terminal of pressure difference transmitter is connected with secondary instrument with lead, and the pressure differential of two sample tap place liquid is sent to secondary instrument with electric signal; Secondary instrument is one with the electric signal of receiving, carries out data processing, and the microcomputer device that shows and print provides instantaneous, the integrated flux of liquid in the pipeline.

The utlity model has following advantage:

1) flow measurement range is wide, easy to use: because of changing measuring sensor, and the hydraulic pressure pressure tappings that only changes diverse location combination can change the range ability ratio of flow and reaches 1:7～9, and as carrying out the adjustment of the range of pressure difference transmitter own again, the range ratio of its flow also can strengthen.

2) measuring accuracy height: measure flow in the pipeline because of available with the different ranges that actual flow adapts, so the corresponding measuring accuracy that improved.

The hydraulic pressure loss is little when 3) measuring, and hydraulic pressure transducer is simple in structure, and is sturdy and durable, easily maintenance.

Describe concrete structure of the present utility model and working condition thereof for example in detail below in conjunction with accompanying drawing.

Fig. 1 is that this flowmeter is installed the back process flow diagram.

Fig. 2 is a flow sensor enlarged diagram in this flowmeter.

With reference to Fig. 1,2, liquid to flow sensor 6, on the inwall of the inboard, corner of sensor 6 bend pipes, is provided with wedge shape fin 7 through pump 5 force feeds, on the tube wall before and after the fin, is provided with the hydraulic pressure sample tap 1,2,3,4 that has valve 8; By the pressure tappings trickle, through the last lower valve of sealing chamber 9, wherein gas and impurity are discharged, and do not make it enter pressure difference transmitter and rest in the pipeline, three valve groups set pipe joint about in the of 10, be connected with pressure difference transmitter 11 and sealing chamber 9 respectively in twos, be provided with equalizing valve in the three valve groups 10, as required, different pressure tappings can be connected, so that veritify the zero point of pressure reduction variator 11,12 is secondary instrument, and 13 is the liquid storehouse.

During use, detailed process is as follows:

1) according to the approximate range of institute's measurement of discharge, selected a pair of pressure tappings, and with valve open on it;

2) open the last valve of sealing chamber 9, will close after discharging by gas in the pipeline;

3) open the lower valve of sealing chamber 9, will be in the liquid precipitation and impurity close after discharging;

4) open two valves and the equalizing valve (not drawing among the figure) that three valve groups are led to pressure difference transmitter, when the electric current of observation pressure difference transmitter 11 outputs is 4mA, show that zero point is normal, close equalizing valve, pressure difference transmitter 11 outputs and the corresponding electric signal of pressure reduction are to secondary instrument;

5) secondary instrument 12 utilization has been solidificated in the calculation procedure in the instrument, changes into input signal instantaneous or integrated flow shows or is printed as literal.

Have in the present embodiment and the contents are as follows:

1) tested condition:

(1) measured medium: water

(2) Media density: 998kg/m ³

(3) working temperature: 20 ℃

(4) working pressure: 2MPa

(5) internal diameter of the pipeline: 50mm

(6) prediction maximum flow: 22t/h

2) adopt the flowmeter situation:

(1) flow sensor internal diameter: D=50mm

(2) select 1151 type condenser type pressure difference transmitters for use, range Δ P=1 * 10 of dispatching from the factory ⁴Pa

(3) according to the spot pressure of flow and differential manometer range employing 2～4 pressure tappings, the flow coefficient k of this combination is demarcated according to test, is input in the computing machine.

(3) measured result

Flow value=22t/h

Pressure differential: 9460Pa

When taking the pressure point of various combination among the utility model embodiment, it is as shown in the table that each group is measured range:

Pressure point array mode	Measurement range
					△Pmin Pa	Qmin?m 3/h	△Pmax Pa	Qmax?m 3/h
	2～3 2～4 1～3 1～4 2～1	880 5000 3170 3000 2930	6.4 16 13 15 26	9500 9460 9920 9720 10000					21 22 23 27 48

As can be seen from the above table, when taking different pressure point array mode, its minimum flow and maximum flow are than being 6.4:48=1:7.5.

Claims (1)

1, the online changeable fluid liquid flowmeter that fluid flow is used in a kind of measuring channel is made of flow sensor, pressure difference transmitter and secondary instrument, it is characterized in that:

1) flow sensor is made of the square bend pipe that two ends connect liquid line, on the inwall of inboard, bend pipe corner, is provided with the wedge shape fin, before and after fin, along on the tube wall of bend pipe, is provided with and the extraneous hydraulic pressure pressure tappings that is connected and has valve 8;

2) input end of pressure difference transmitter 11 has two pipe interfaces, can be connected with the pressure pipeline of two various combinations, the output terminal of pressure difference transmitter is connected with secondary instrument with lead, and the pressure differential of two sample tap place liquid is sent to secondary instrument 12 with electric signal.

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