CN109060884A - A kind of liquid natural gas gasification rate measurement method - Google Patents
A kind of liquid natural gas gasification rate measurement method Download PDFInfo
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- CN109060884A CN109060884A CN201810716483.3A CN201810716483A CN109060884A CN 109060884 A CN109060884 A CN 109060884A CN 201810716483 A CN201810716483 A CN 201810716483A CN 109060884 A CN109060884 A CN 109060884A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
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Abstract
The invention discloses a kind of liquid natural gas gasification rate Detection & Controling methods, comprising the following steps: meter ontology is connected to the vaporizer of testing liquid natural gas；Thermistor and flow velocity compensation resistance is respectively set in the air inlet and inside exhaust ports of the vaporizer, constitutes bridge circuit with the intrinsic precision resistance of meter and amendable precision resistance；The temperature difference of temperature and flow velocity the compensation resistance of thermistor is definite value, and when the gasification rate of liquid natural gas in vaporizer changes, temperature and resistance value added with the thermistor of electric current, which will change, makes bridge circuit deviate balance, exports unbalanced signal；The amplified feedback of the unbalanced signal, by adjusting the voltage between flow velocity compensation resistance and thermistor, makes bridge circuit restore balance, gasification rate is made to restore normal into bridge circuit.The present invention realizes the high-acruracy survey and control of liquid natural gas gasification rate, save the cost and reduction environmental pollution.
Description
Technical field
The present invention relates to field of measuring technique, and in particular to a kind of liquid natural gas gasification rate measurement method.
Background technique
Natural gas is essential important energy source in people's life and work, and wherein liquefied natural gas is the shape with liquid
Formula storage usually utilizes the natural gas of gas but when practical application, therefore, it is necessary to by liquefied natural gas into
Promoting the circulation of qi.In the gasification to liquefied natural gas, gasification deficiency can then cause failure, and gasification is excessive then to will lead to natural gas
Waste and environmental pollution.Therefore, it in the gasification of liquefied natural gas, needs to carry out essence to the gasification rate of liquid natural gas
True measurement is precisely controlled liquefied natural gas gasifying process to realize.
For the problems in the relevant technologies, currently no effective solution has been proposed.
Summary of the invention
The technical problem to be solved by the present invention is to how to be accurately measured to liquid natural gas boil-off rate, to realize
The problem of liquid natural gas gasification is precisely controlled.
In order to solve the above-mentioned technical problem, the technical scheme adopted by the invention is that providing a kind of liquid natural gas gasification speed
Rate Detection & Controling method, comprising the following steps:
Meter ontology is connected to the vaporizer of testing liquid natural gas；
Thermistor and flow velocity compensation resistance is respectively set in the air inlet and inside exhaust ports of the vaporizer, with measurement
It counts intrinsic precision resistance and amendable precision resistance constitutes bridge circuit；
Wherein, the temperature difference of the temperature of thermistor and flow velocity compensation resistance is definite value, when gasification indoor liquid is natural
When the gasification rate of gas changes, temperature and resistance value added with the thermistor of electric current will change and deviate bridge circuit
Balance, to export unbalanced signal；The amplified feedback of the unbalanced signal is into bridge circuit, by adjusting flow velocity compensation
Voltage between resistance and thermistor, makes bridge circuit restore balance, so that gasification rate be made to restore normal.
In the above scheme, when the indoor flow that gasifies changes, the gasification rate of liquid natural gas changes therewith,
Voltage between temperature, resistance value and thermistor and flow velocity the compensation resistance of thermistor is directly proportional to the size of gasification rate
Variation, the voltage swing between load voltage and thermistor and flow velocity the compensation resistance of servo amplifier is inversely proportional variation, hot
The variation directly proportional to the load voltage size of servo amplifier of the voltage of quick resistance both end voltage and bridge circuit.
In the above scheme, when the gasification rate of liquid natural gas becomes larger, the temperature and resistance value of thermistor are reduced, heat
Voltage between quick resistance and flow velocity compensation resistance decreases；The reduction of voltage is drawn between thermistor and flow velocity compensation resistance
The load voltage for having played servo amplifier increases, so that the voltage of the increase of thermistor both end voltage and bridge circuit be made to increase
Add；The voltage increase of bridge circuit causes to increase by the electric current of thermistor, and it is quick to reheat the integrated temperature of thermistor
Sensing unit makes thermistor and flow velocity compensate the voltage between resistance and increases, reduces thermistor both end voltage, restore electric bridge
Balance makes gasification rate restore normal.
In the above scheme, the resistance value of precision resistance is 100 Ω；The Standard resistance range of amendable precision resistance is 0-200
Ω；The water triple point resistance that thermistor passes through thermometer measure is (100 ± 1) Ω；Flow velocity compensates resistance and is measured by temperature
The water triple point resistance of amount is (25 ± 1) Ω.
In the above scheme, the temperature-sensing element (device) and thermistor temperature coefficient having the same.
In the above scheme, the temperature-sensing element (device) is made of the coil with larger area.
In the above scheme, the precision resistance is connected with the thermistor, and by the two of the precision resistance
Output signal of the voltage swing as the liquid natural gas gasification rate size is held, when the both end voltage of the precision resistance increases
When big, indicate that the liquid natural gas gasification rate becomes larger, otherwise, it means that the liquid natural gas gasification rate becomes smaller.
The present invention be directed to liquefied natural gas gasifying during, how the size of accurate perception amount of vaporization, provide a kind of liquid
Body natural gas gasifying rate Detection & Controling method can be drawn in gasification by temperature change by detecting liquefied natural gas
The mode of the resistance variation risen, indirectly accurately measures the size of the gasification rate of liquid natural gas, passes through tune
It is uneven to save the electric bridge due to caused by the variation of gasification rate, keeps the electric bridge rate recovery that restores balance and gasify normal, thus
Realization is precisely controlled liquefied natural gas gasifying process.Measurement method of the invention is simple and reliable, and measurement range is wider, and surveys
Accuracy of measurement is higher, can prevent liquid natural gas gasification is insufficient to cause natural gas waste and environment caused by failure and gasification excess
Pollution, to realize the high-acruracy survey of liquid natural gas gasification rate, save the cost and reduce environmental pollution.
Detailed description of the invention
Fig. 1 is a kind of liquid natural gas gasification rate Detection & Controling method flow diagram of the invention.
Specific embodiment
The present invention is described in detail with reference to the accompanying drawings of the specification.
As shown in Figure 1, a kind of liquid natural gas gasification rate Detection & Controling method provided by the invention, including following step
It is rapid:
S101, the vaporizer that meter ontology is connected to testing liquid natural gas；
S102, vaporizer air inlet and inside exhaust ports be respectively set thermistor and flow velocity compensation resistance, with survey
The intrinsic precision resistance of meter and amendable precision resistance constitute bridge circuit；
The temperature difference of S103, the temperature of thermistor and flow velocity compensation resistance are definite value, when gasification indoor liquid is natural
When the gasification rate of gas changes, temperature and resistance value added with the thermistor of electric current will change and deviate bridge circuit
Balance, to export unbalanced signal；
The amplified feedback of S104, the unbalanced signal compensates resistance and temperature-sensitive into bridge circuit, by adjusting flow velocity
Voltage between resistance, makes bridge circuit restore balance, so that gasification rate be made to restore normal.
Optionally, when the indoor flow that gasifies changes, the gasification rate of liquid natural gas changes therewith, temperature-sensitive electricity
Voltage variation directly proportional to the size of gasification rate between temperature, resistance value and thermistor and flow velocity the compensation resistance of resistance,
Voltage swing between load voltage and thermistor and flow velocity the compensation resistance of servo amplifier is inversely proportional variation, thermistor
The variation directly proportional to the load voltage size of servo amplifier of the voltage of both end voltage and bridge circuit.
Optionally, when the gasification rate of liquid natural gas becomes larger, the temperature and resistance value of thermistor are reduced, thermistor
Voltage between flow velocity compensation resistance decreases；The reduction of voltage, which causes, between thermistor and flow velocity compensation resistance watches
The load voltage for taking amplifier increases, so that the voltage of the increase of thermistor both end voltage and bridge circuit be made to increase；Electric bridge
The voltage increase of circuit causes to increase by the electric current of thermistor, reheats the integrated temperature-sensing element (device) of thermistor,
Make thermistor and flow velocity compensate the voltage between resistance to increase, reduces thermistor both end voltage, so that electric bridge is restored balance, make
Gasification rate restores normal.
Optionally, the resistance value of precision resistance is 100 Ω；The Standard resistance range of amendable precision resistance is 0-200 Ω；Temperature-sensitive
The water triple point resistance that resistance passes through thermometer measure is (100 ± 1) Ω；Flow velocity compensates the water three that resistance passes through thermometer measure
Phase point resistance is (25 ± 1) Ω.In addition, those skilled in the art can also choose suitable resistance according to actual needs,
Which is not limited by the present invention.
Optionally, the resistance wire of temperature-sensing element (device) and thermistor temperature coefficient having the same, thermistor uses
Platinum wire material.
Optionally, temperature-sensing element (device) is made of the coil with larger area.
Optionally, precision resistance is connected with thermistor, and using the both end voltage size of precision resistance as liquid
The output signal of natural gas gasifying rate size indicates liquid natural gas gasification speed when the both end voltage of precision resistance increases
Rate becomes larger, otherwise, it means that liquid natural gas gasification rate becomes smaller.
Optionally, meter body interior is integrated with the adjustable of integrated circuit and the power supply size for adjusting bridge circuit
Voltage source, integrated circuit amplify output signal, while being converted to number for controlling outputting and inputting for bridge circuit
Word signal；Output end includes for measuring the potentiometer of precision resistance both end voltage size, putting down for adjusting bridge circuit voltage
The bridge balance potentiometer of weighing apparatus and for measuring the electric current for flowing through two bridge arm size of current of thermistor and precision resistance
Meter.
Technical solution to facilitate the understanding of the present invention, is below described in detail technical solution of the present invention.
Arrange that thermistor, liquefied natural gas become gaseous process from liquid evaporation and take away heat in liquefied natural gas gasifying room
It measures and declines thermistor temp, liquefied natural gas gasifying rate is faster, then it is more to take away heat, at a temperature of thermistor
It drops more.An arm of the thermistor as electric bridge, it is the resistance with positive temperature coefficient, then electric upon a drop in temperature
Resistance value becomes smaller, and becoming smaller for resistance value causes bridge circuit uneven at this time.When bridge circuit imbalance occurs, bridge balance electricity
Pressure meter inputs unbalanced signal to integrated circuit, and integrated circuit amplifies unbalanced signal and is converted to digital signal output
Thermistor is set to keep constant temperature to adjustable voltage power supply and galvanometer, it is constant and make bridge circuit to reach thermistor resistance value
It restores balance, if gasification rate increases at this time, electric current increases；Gasification rate reduces, then electric current reduces.
Wherein, the temperature difference of the temperature of thermistor and flow velocity compensation resistance is definite value, is controlled under normal circumstances 100
DEG C, when the thermistor added with electric current is placed in flow field, due to fluid-flow relation, thermistor temp changes,
This change immediately results in electric bridge and deviates balance, so that unbalanced signal is exported, the amplified feedback of the unbalanced signal to electricity
In bridge circuit, to inhibit the temperature of thermistor to change, the variation of thermistor resistance is compensated, so that bridge circuit be made to restore flat
Weighing apparatus.
Control process is as follows: when the flow inside vaporizer increases, thermistor temp is reduced, thermistor resistance value drop
Low, the voltage between thermistor and flow velocity compensation resistance decreases；Voltage between thermistor and flow velocity compensation resistance
The load voltage increase for causing servo amplifier is reduced, so that thermistor both end voltage be made to increase；So as to cause electric bridge electricity
The increase of pressure；The increase of bridge voltage causes to increase by the electric current of thermistor, then reheats thermistor and be internally integrated
Temperature-sensing element (device), increased so that thermistor and flow velocity be made to compensate the voltage between resistance, reduce thermistor both ends electricity
Pressure, makes bridge circuit restore balance.
Precision resistance is connected with thermistor, and the electric current of series circuit is equal, and the electric current of thermistor again flows through precision
At this moment the power cathode of resistance generates a voltage, the variation of this voltage swing and size of current variation on precision resistance
The variation of directly proportional and gasification rate is directly proportional.The voltage swing at the precision resistance both ends is believed as the output of gasification rate size
Number.
In the case where liquefied natural gas gasifying amount is constant, when gas flow rate is different, the heat taken away from thermistor
Also different, therefore resistance is compensated using flow velocity in bridge circuit.After flow velocity compensation resistance is arranged in liquefied natural gas gasifying
Pipeline in, flow velocity compensation resistance change in resistance with gasification rate change and change, thus change bridge circuit balance, make
Measurement error caused by flow velocity is different is compensated, to guarantee the accuracy of measurement.
Flow velocity compensation resistance is integrated by series and parallel compensated resistance, and one of resistance is temperature-sensing element (device), it is arranged on
In flow field identical with thermistor, and with thermistor temperature coefficient having the same.Manufacturing the sensitive member of the upper temperature
Part is made of the coil with larger area.When known to the resistance value of series and parallel compensated resistance, voltages keep constant can be extrapolated
Series resistance and parallel resistance resistance value.
The present invention be directed to liquefied natural gas gasifying during, how the size of accurate perception amount of vaporization, provide a kind of liquid
Body natural gas gasifying rate Detection & Controling method can be drawn in gasification by temperature change by detecting liquefied natural gas
The mode of the resistance variation risen, indirectly accurately measures the size of the gasification rate of liquid natural gas, passes through tune
It is uneven to save the electric bridge due to caused by the variation of gasification rate, keeps the electric bridge rate recovery that restores balance and gasify normal, thus
Realization is precisely controlled liquefied natural gas gasifying process.Measurement method of the invention is simple and reliable, and measurement range is wider, and surveys
Accuracy of measurement is higher, can prevent liquid natural gas gasification is insufficient to cause natural gas waste and environment caused by failure and gasification excess
Pollution, to realize the high-acruracy survey of liquid natural gas gasification rate, save the cost and reduce environmental pollution.
The present invention is not limited to above-mentioned preferred forms, and anyone should learn that the knots made under the inspiration of the present invention
Structure variation, the technical schemes that are same or similar to the present invention are fallen within the scope of protection of the present invention.
Claims (7)
1. a kind of liquid natural gas gasification rate Detection & Controling method, which comprises the following steps:
Meter ontology is connected to the vaporizer of testing liquid natural gas；
Thermistor and flow velocity compensation resistance is respectively set in the air inlet and inside exhaust ports of the vaporizer, with meter sheet
Intracorporal precision resistance and amendable precision resistance constitute bridge circuit；
Wherein, the temperature difference of the temperature of thermistor and flow velocity compensation resistance is definite value, when liquid natural gas in vaporizer
When gasification rate changes, temperature and resistance value added with the thermistor of electric current, which will change, keeps bridge circuit deviation flat
Weighing apparatus, to export unbalanced signal；The amplified feedback of the unbalanced signal is into bridge circuit, by adjusting flow velocity compensation electricity
Voltage between resistance and thermistor, makes bridge circuit restore balance, so that gasification rate be made to restore normal.
2. liquid natural gas gasification rate Detection & Controling method as described in claim 1, which is characterized in that when in vaporizer
Flow when changing, the gasification rate of liquid natural gas changes therewith, temperature, resistance value and the thermistor of thermistor
Voltage variation directly proportional to the size of gasification rate between flow velocity compensation resistance, the load voltage and temperature-sensitive of servo amplifier
Voltage swing between resistance and flow velocity compensation resistance is inversely proportional variation, the voltage of thermistor both end voltage and bridge circuit
Variation directly proportional to the load voltage size of servo amplifier.
3. liquid natural gas gasification rate Detection & Controling method as claimed in claim 2, which is characterized in that when liquid is natural
When the gasification rate of gas becomes larger, the temperature and resistance value of thermistor are reduced, the voltage between thermistor and flow velocity compensation resistance
It decreases；The load voltage that the reduction of voltage causes servo amplifier between thermistor and flow velocity compensation resistance increases,
To make thermistor both end voltage increase and the increase of the voltage of bridge circuit；The voltage increase of bridge circuit causes to pass through heat
The electric current of quick resistance increases, and reheats the integrated temperature-sensing element (device) of thermistor, and thermistor and flow velocity is made to compensate resistance
Between voltage increase, reduce thermistor both end voltage, electric bridge made to restore balance, gasification rate is made to restore normal.
4. liquid natural gas gasification rate Detection & Controling method as claimed in claim 3, which is characterized in that precision resistance
Resistance value is 100 Ω；The Standard resistance range of amendable precision resistance is 0-200 Ω；Thermistor passes through the water three of thermometer measure
Phase point resistance is (100 ± 1) Ω；It is (25 ± 1) Ω that flow velocity, which compensates the water triple point resistance that resistance passes through thermometer measure,.
5. liquid natural gas gasification rate Detection & Controling method as claimed in claim 3, which is characterized in that the temperature is quick
Sensing unit and thermistor temperature coefficient having the same.
6. liquid natural gas gasification rate Detection & Controling method as claimed in claim 5, which is characterized in that the temperature is quick
Sensing unit is made of the coil with larger area.
7. liquid natural gas gasification rate Detection & Controling method as described in claim 1, which is characterized in that by the precision
Resistance is connected with the thermistor, and the both end voltage size of the precision resistance is gasified as the liquid natural gas
The output signal of rate size indicates the liquid natural gas gasification rate when the both end voltage of the precision resistance increases
Become larger, otherwise, it means that the liquid natural gas gasification rate becomes smaller.
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| CN2160904Y (en) * | 1993-06-15 | 1994-04-06 | 杨彦 | Liquid-and gas-state detector for refrigerating medium |
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Application publication date: 20181221 |