CN201681320U - Gas pressure and flow control device of humidity generator - Google Patents
Gas pressure and flow control device of humidity generator Download PDFInfo
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- CN201681320U CN201681320U CN 201020142152 CN201020142152U CN201681320U CN 201681320 U CN201681320 U CN 201681320U CN 201020142152 CN201020142152 CN 201020142152 CN 201020142152 U CN201020142152 U CN 201020142152U CN 201681320 U CN201681320 U CN 201681320U
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Abstract
The utility model relates to a humidity generator, belonging to the field of a two-pressure humidity generator, in particular to a gas pressure and flow control device of a humidity generator, comprising a saturator part and a testing room part, wherein the front part of the inlet of the saturator part is connected with an air source by an inlet valve, and the back part of the outlet of the saturator part is connected with the testing room part by an expansion valve. The utility model is characterized in that the inlet valve adopts a regulating valve controlled by a pressure controller, and the saturator is provided with a pressure sensor which is electrically connected with the input port of the pressure controller to output a pressure value feedback signal to the pressure controller. The output port of the pressure controller is electrically connected with the drive motor of the regulating valve, and the pressure controller is provided with a set voltage input interface. The input interface and the output port are respectively connected with the pressure setting module of a center controller, and the drive motor of the expansion valve is electrically connected with the flow control module of the center controller.
Description
Technical field
The utility model relates to a kind of humidity generator, relates in particular to the gaseous tension and the volume control device of humidity generator.
Background technology
The principle of work of two platen press standard humidity generators be gas under pressurized state by water-vapo(u)r saturation puffing then, different relative humidity takes place by the pressure that changes saturator.Therefore the pressure controlled degree of stability of saturator directly influences the uncertainty of the humidity of generator generation.In control saturator pressure, the sample airshed in the saturator of flowing through within the specific limits should be able to free adjustment.Two pressure humidity generators are made up of following six parts usually: air supply system; The carrier gas drying system; The saturator system; Test chamber; Constant temperature system; The measurement and control system of temperature and pressure.
Be the ultimate principle of standard humidity generator as shown in Figure 1, regulate the gas admittance valve of saturator among the figure and the expansion valve between saturator and the test cabinet, can make the pressure P s of saturator and the flow Q by saturator can both stably reach predetermined value by interlock.
Realize above function, the following two kinds of ways of general now use:
One, gas admittance valve and expansion valve all use manually, and by constantly observing the variation of saturator pressure displayed value and flow displayed value, the aperture of manual adjustments gas admittance valve and expansion valve makes pressure P s and flow Q finally reach predetermined value simultaneously.The operation easier of the method is very big, is difficult to reach pressure stable Ps.
Two, control charge flow rate method.Replace gas admittance valve with a mass flow controller (band variable valve), keep a constant charge flow rate Q, by constantly observing the variation of saturator pressure displayed value, the aperture of manual adjustments expansion valve makes pressure P s finally reach predetermined value simultaneously then.Though the operation of the method manually makes progress entirely than above-mentioned, but it is also very difficult, because will observe the trend that pressure changes when regulating constantly, even under the situation that expansion valve opening is fixed, also there is slow drift phenomenon in pressure P s, therefore as keeping pressure stable, the operator just must note also timely adjustment expansion valve constantly, and operation is trouble and unstable very.
Summary of the invention
Technical problem to be solved in the utility model provides a kind of gaseous tension of humidity generator and the method and apparatus of flow control, solves present troublesome poeration but the not high defective of precision.
Technical scheme
A kind of gaseous tension of humidity generator and volume control device, comprise saturator part and test cabinet part, before partly entering the mouth, saturator links to each other with source of the gas by gas admittance valve, partly be connected with test cabinet by expansion valve behind the saturator section port, it is characterized in that: described gas admittance valve adopts the variable valve of the controller control that is stressed, saturator is provided with pressure transducer, described pressure transducer is electrically connected with the input port of pressure controller, the output pressure value feeds back signal to pressure controller, the output port of pressure controller is electrically connected with the drive motor of variable valve, described pressure controller has the setting voltage input interface, input interface all links to each other with the pressure setting module of central control unit with output port, and the drive motor of described expansion valve is electrically connected with the flow-control module of central control unit.
Further, described pressure transducer is provided with a plurality of according to the range difference and has continuous range, and selects module to be connected by switch with the sensor of pressure controller and central control unit.
Described sensor selects module to comprise synchronous submodule, and described synchronous submodule connects pressure controller by the pressure setting module.
Described pressure transducer uses four, and each pressure transducer is connected with switch respectively.
Described switch adopts the combination of relay coupling solenoid valve.
Further, described expansion valve adopts a plurality of expansion valves with different coefficient of flow to carry out parallel connection, and selects module to be connected with the expansion valve of central control unit.
Described test cabinet partly is equipped with flow instrument, and described flow instrument is electrically connected with the flow-control module of central control unit.
The drive motor of described expansion valve adopts stepper motor, and expansion valve adopts needle valve, and the valve rod of described needle valve links to each other with stepper motor by shaft coupling, and the pedestal of described stepper motor is fixed on the slide block of the guide rail parallel with the needle valve valve rod.
Beneficial effect
The utility model adopts the pressure of the saturator of direct controlled humidity generator, after pressure reaches setting value, pass through the aperture of stepper motor variable expansion valve again, make flow reach setting value, thereby produce the relative humidity that needs, advantage is that pressure moment autostable is on setting value, thereby the pressure transient phenomenon that the method for having avoided in the past being adopted causes, because two humidity generators of pressing are higher than discharge stability far away for the requirement of pressure stability, therefore directly the method tool of controlled pressure has an enormous advantage, the utility model switches and mode relatively by different range pressure sensor signals of multichannel and corresponding setting voltage signal Synchronization, improve the resolution of pressure signal, thereby realized pressure controlled high stability.
Description of drawings
Fig. 1 is the basic principle schematic of two platen press standard humidity generators;
Fig. 2 is the gas circuit schematic block diagram of control device of the present utility model;
Fig. 3 is the schematic block circuit diagram of control device of the present utility model;
Fig. 4 is the structural representation that stepper motor drives aciculiform expansion valve valve rod in the control device of the present utility model.
Wherein among Fig. 4: 1-guide rail, 2-slide block, 3-stepper motor pedestal, 4-stepper motor, 5-shaft coupling, 6-aciculiform expansion valve valve rod.
Embodiment
Below in conjunction with specific embodiment, further set forth the utility model.
Because the very wide (5kPa～1000kPa) of the working pressure range of saturator, in order directly to control the degree of accuracy and the degree of stability of saturator pressure, the precision of the pressure transducer of single range and degree of stability can not meet the demands, and therefore the pressure of saturator are regulated segmentation and carry out.
Pressure range of adjustment with saturator is that 95kPa～1050kPa (absolute pressure) is an example, sees Fig. 2 pneumatic diagram, for improving the resolution of pressure measurement signal, divides four sections with whole pressure limit, that is:
1) 250kPa＞Ps 〉=95kPa (pressure transducer 4, range 0～0.25MPa);
2) 350kPa＞Ps 〉=250kPa (pressure transducer 3, range 0.25～0.4MPa);
3) 600kPa＞Ps 〉=350kPa (pressure transducer 2, range 0.4～0.6MPa);
4) 1050kPa 〉=Ps 〉=600kPa (pressure transducer 1, range 0.6～1.0MPa);
Circuit connects as shown in Figure 3, pressure controller is arranged on before the saturator air intake opening, after 1～5V setting signal calculates corresponding saturator force value by central control unit according to the humidity value of setting, export by the pressure setting module, central control unit can be constituted jointly by the PLC of computing machine and control, and 16 D/A cards of built-in computer are responsible for output as the pressure setting module; The pressure sensor signal of 1～5V comes from the pressure transducer of 4 tunnel different ranges, and PLC is according to different working pressures, and the synchronous switching by solenoid valve and relay realizes.The signal of D/A card output also switches according to the switching of pressure transducer range is corresponding synchronously.Therefore select to comprise synchronous submodule in the module at sensor, sensor is selected switching and pressure set points output synchronously.Can be implemented in the total pressure scope synchronously by this, in the scope of flow 6～25L/mi n, the pressure stability degree of saturator for a long time (more than 1 hour) be controlled at automatically reading 0.01% in, thereby satisfied the technical requirement of installing fully.
Owing to be used for the pressure controller of pressure gauge calibrating, its control stabilization degree is also very little, but they can only produce static pressure (only allow small flow), adopt the pressure control of so synchronous comparison to realize also can reaching the pressure control of high stability under bigger working flow condition.
After pressure reaches setting value, be computer control PLC output by central control unit, and then the drive controlling stepper motor is regulated flow.(5～30L/min), and as requested, the pressure reduction variation range of the expansion valve front and back before the test cabinet reaches 5kPa～900kPa, and this just requires the coefficient of flow k of expansion valve because the matching requirements flow adjustment range is bigger
vThe value range of adjustment reaches more than 100 times, therefore needs the different k of two-way at least
vThe expansion valve of value is in parallel could be realized, the force value that the switching point of two-way expansion valve can be decided to be saturator is switched during for 400kPa, be central control unit when switching to pressure transducer 3 work, expansion valve selects module output signal to switch expansion valve synchronously.
By computer control PLC output, thereby drive stepping motor realizes that the flow of expansion valve is regulated automatically.After PLC received flow setting value from computing machine, according to the measured discharge value of the flow instrument that is provided with, relatively the back was by flow-control module control expansion valve.Control mode can adopt the progressively gradient minimizing of aperture of variable expansion valve, finally reaches stability of flow.In case after stable, stepper motor is no longer action before not receiving new flow setting value.When pressure, flow setting value had one to change, motor returned zero-bit earlier.Also can establish upper limit optoelectronic position in addition and detect, excessively open to prevent valve.
Because adopting stepper motor accurately controls the aciculiform expansion valve, thereby need to solve valve rod and when being rotated, influence the problem that the needle-valve aperture influences flow owing to produce faint axial displacement by driven by motor, as shown in Figure 4, the pedestal of stepper motor is installed on the slide block that is arranged on axial guidance, can move up and down along guide rail, thereby solve the problems referred to above.
Device of the present utility model directly adopts pressure controller control saturator pressure.Under the control of computing machine and PLC, by the mode that different range pressure sensor signals of multichannel and corresponding computer settings voltage signal switch synchronously, improved the resolution of pressure signal, realized pressure controlled high stability.Simultaneously, adopt the mode of computing machine and the automatic step motor control needle valve of PLC aperture to regulate flow.The output shaft of stepper motor directly is connected with the needle valve valve rod, and stepper motor is fixed on the guide rail parallel with output shaft by flexible clutch, when rotating, produces the problem that axial displacement influences flow control thereby solved valve rod.
Claims (8)
1. the gaseous tension of a humidity generator and volume control device, comprise saturator part and test cabinet part, before partly entering the mouth, saturator links to each other with source of the gas by gas admittance valve, partly be connected with test cabinet by expansion valve behind the saturator section port, it is characterized in that: described gas admittance valve adopts the variable valve of the controller control that is stressed, saturator is provided with pressure transducer, described pressure transducer is electrically connected with the input port of pressure controller, the output pressure value feeds back signal to pressure controller, the output port of pressure controller is electrically connected with the drive motor of variable valve, described pressure controller has the setting voltage input interface, input interface all links to each other with the pressure setting module of central control unit with output port, and the drive motor of described expansion valve is electrically connected with the flow-control module of central control unit.
2. the gaseous tension of a kind of humidity generator as claimed in claim 1 and volume control device, it is characterized in that: described pressure transducer is provided with a plurality of according to the range difference and has continuous range, and selects module to be connected by switch with the sensor of pressure controller and central control unit.
3. the gaseous tension of a kind of humidity generator as claimed in claim 2 and volume control device is characterized in that: described sensor selects module to comprise synchronous submodule, and described synchronous submodule connects pressure controller by the pressure setting module.
4. the gaseous tension of a kind of humidity generator as claimed in claim 2 and volume control device is characterized in that: described pressure transducer uses four, and each pressure transducer is connected with switch respectively.
5. as the gaseous tension and the volume control device of claim 2 or 4 described a kind of humidity generators, it is characterized in that: described switch adopts the combination of relay coupling solenoid valve.
6. the gaseous tension of a kind of humidity generator as claimed in claim 1 and volume control device is characterized in that: described expansion valve adopts a plurality of expansion valves with different coefficient of flow to carry out parallel connection, and selects module to be connected with the expansion valve of central control unit.
7. as the gaseous tension and the volume control device of claim 1 or 6 described a kind of humidity generators, it is characterized in that: described test cabinet partly is equipped with flow instrument, and described flow instrument is electrically connected with the flow-control module of central control unit.
8. as the gaseous tension and the volume control device of claim 1 or 6 described a kind of humidity generators, it is characterized in that: the drive motor of described expansion valve adopts stepper motor, expansion valve adopts needle valve, the valve rod of described needle valve links to each other with stepper motor by shaft coupling, and the pedestal of described stepper motor is fixed on the slide block of the guide rail parallel with the needle valve valve rod.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201020142152 CN201681320U (en) | 2010-03-26 | 2010-03-26 | Gas pressure and flow control device of humidity generator |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201020142152 CN201681320U (en) | 2010-03-26 | 2010-03-26 | Gas pressure and flow control device of humidity generator |
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| CN201681320U true CN201681320U (en) | 2010-12-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 201020142152 Expired - Fee Related CN201681320U (en) | 2010-03-26 | 2010-03-26 | Gas pressure and flow control device of humidity generator |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105805087A (en) * | 2016-05-09 | 2016-07-27 | 中国重型机械研究院股份公司 | Multistage-pressure automatic switching detection device |
| CN107727400A (en) * | 2017-09-11 | 2018-02-23 | 奇瑞汽车股份有限公司 | Engine charge pressure test system and its control method |
-
2010
- 2010-03-26 CN CN 201020142152 patent/CN201681320U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105805087A (en) * | 2016-05-09 | 2016-07-27 | 中国重型机械研究院股份公司 | Multistage-pressure automatic switching detection device |
| CN107727400A (en) * | 2017-09-11 | 2018-02-23 | 奇瑞汽车股份有限公司 | Engine charge pressure test system and its control method |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101222 Termination date: 20130326 |