CN2095405U

CN2095405U - Mass flowmeter

Info

Publication number: CN2095405U
Application number: CN 91206054
Authority: CN
Inventors: 赵景周; 王文福; 苏化莲
Original assignee: Shanxi Institute of Coal Chemistry of CAS
Current assignee: Shanxi Institute of Coal Chemistry of CAS
Priority date: 1991-04-11
Filing date: 1991-04-11
Publication date: 1992-02-05

Abstract

The utility model provides a mass flowmeter which measures flow by measuring temperature changes at both ends of fluid. The utility model comprises a gas inlet, a gas outlet, and a capillary pipe which is communicated with the gas inlet and the gas outlet. The capillary pipe is wound with a heating coil of which both ends are respectively provided with a temperature sensitive element to measure the temperature difference between both ends of the heating coil. The middle part of a channel where the gas inlet and the gas outlet are communicated is provided with a metering range adjusting valve which is composed of a valve seat and a metering range adjusting rod, wherein, the head part of the metering range adjusting rod forms a needle shape and the metering range adjusting rod controls the open-close degree of the valve seat. The utility model has wide use range due to the adjustable metering range.

Description

Mass flowmeter

The utility model belongs to the measurement mechanism of mass rate, particularly a kind of mass flowmeter of measuring flow to measure fluid two ends temperature variation indirectly.

Laboratory mass flowmeter commonly used generally is that fluid is heated by a kapillary that is wound with heater coil, set up sampled point at two ends near heater coil, temperature variation with its upstream and downstream of temperature sensor measurement, thereby temperature difference of demonstrating (potential difference (PD)), form one regularly when fluid, the flow and the temperature difference are linear in a certain flow rates.This thermal type mass flowmeter structure is comparatively simple, but that shortcoming is a range is non-adjustable, and as 5800 series mass flowmeters from U.S.'s import, outward appearance is small and exquisite, costs an arm and a leg, but because range is non-adjustable, its use is restricted.In addition, the thermal type mass flowmeter that uses and sell mostly adopts thermal sensing element to come detected temperatures at present, thereby must use complicated bridge circuit that detection signal is carried out linear process in Circuits System.

The purpose of this utility model is to provide a kind of mass flowmeter of measuring range adjustable, adopts temperature sensing element to detect the pest degree, can not only widen usable range greatly, and circuit is simpler.

Mass flowmeter of the present utility model is such: it comprises the passage of gas inlet and outlet and connection, at the kapillary that a semicircular in shape is installed near the two ends of gas inlet and outlet, gas is passed through, electrically-heated coil is twined on top capillaceous, the coil two ends are provided with temperature sensing element, the channel middle that is communicated with at gas inlet and outlet is provided with a range variable valve and regulates in order to the range to gas, and the range variable valve is made of the range adjuster bar of the may command valve seat folding degree that a valve seat and head are needle-like.

Mass flowmeter of the present utility model is used the shunting principle of fluid, at the medium position of gas inlet and outlet passage the range variable valve is set, and has solved all nonadjustable shortcoming of present mass flowmeter range, thereby has widened its usable range greatly.This flowmeter is owing to adopt temperature sensing element to detect the temperature at heater coil two ends, thereby saved the bridge diagram that the run-of-the-mill flowmeter is adopted, and Circuits System simplified, and had advantages of higher stability and degree of accuracy.

To provide embodiment of the present utility model by accompanying drawing below, and elaborate.

Fig. 1 is according to the mass flowmeter sectional view that the utility model proposes.

Fig. 2 is the Circuits System block diagram of this flowmeter.

1 is the gas access among the figure, the 2nd, and temperature sensing element, the 3rd, kapillary, the 4th, heater coil, the 5th, gas vent, the 6th, mass flowmeter housing, the 7th, valve seat, the 8th, pressure cap, the 9th, sealing ring, the 10th, range adjuster bar, the 11st, adjusting handle.

Housing 6 both sides are opened gas access 1 respectively, gas vent 5 and corresponding gas communication passage thereof, the kapillary 3 of a semicircular in shape is installed on top, and air inlet/outlet capillaceous is communicated with the access way of gas, and a range variable valve is set at the middle part of gas inlet and outlet passage.Gas enters mass flowmeter by inlet 1, there is portion gas can flow through kapillary 3 and is heated thin circle 4 heating backs and pass through outlet, the two ends of heater coil are provided with temperature detecting point, measure temperature with temperature sensing element 2, demonstrate the temperature difference (being potential difference (PD)) therefrom, when gas composition one timing, the flow and the temperature difference are linear in a certain flow rates, obtain needed flow indication after can handling the signal that collects by corresponding circuit.By inlet 1 gas that enters except that part by the kapillary 3, major part will be flowed through behind the range variable valve by outlet.The range variable valve is that the range adjuster bar 10 of needle-like constitutes by valve seat 7 and head mainly, for preventing gas leakage, adjuster bar top seals with sealing ring 9, pressure cap 8 is connected with adjuster bar 10 usefulness engage thread, an adjusting handle 11 is installed in the bottom of adjuster bar, rotate adjusting handle 11, the adjuster bar head that makes needle-like that moves up and down is in the different foldings position of valve seat, thereby realizes the purpose of measuring range adjustable.

Mass flowmeter of the present utility model can select for use metal material to make, as stainless steel, valve seat bore is 1.2mm, selected temperature sensitive original paper can be AD590, select for use this element directly to provide potential difference signal, in Circuits System, can save bridge diagram, adopt direct computing amplification after the mode of analog to digital conversion input single-chip microcomputer, circuit is simpler, and circuit block diagram is seen Fig. 2.The components and parts of circuit are selected and are communicated with all is that those skilled in the art can accomplish.Its basic mechanical design feature of the mass flowmeter of the foregoing description is: working pressure: normal pressure-22MPa; Serviceability temperature: 10 ℃-40 ℃; Can regulate continuously between range ability: the 0-1.5L/h to 0-600L/h; Output signal: 200mv; Precision: 1.5% shows: instantaneous delivery, integrated flow and clock show that by numeral there is power-off protection in system.

Claims

1, a kind of mass flowmeter that comes measurement of discharge with measurement fluid two ends temperature variation, comprise gas inlet and outlet and the kapillary that communicates with import and export, be wound with heater coil on the kapillary, it is characterized in that the temperature difference that a temperature sensing element is measured the coil two ends being set respectively at the two ends of heater coil, the channel middle that is communicated with at gas inlet and outlet is provided with a range variable valve, and the range variable valve is made of the range adjuster bar of the may command valve seat folding degree that a valve seat and head are needle-like.