Now in conjunction with the accompanying drawings the structure of supercritical fluid extraction instrument is described in detail.
By Fig. 1,2, have the CO of intubate
2Pressure gauge 2 is housed on the steel cylinder 1, be connected in micro-processor controlled high-pressure pump 4 by pipeline and input stop valve 3, be connected in output stop valve 5 by pipeline again, be connected to four-way connection 6 by pipeline, this joint 6 two is terminated at inlet valve 7 in addition, 8, the other end is connected to atmospheric valve 9, in the extraction tank furnace case 12 abstraction pool 10 is housed, 11, each joins with inlet valve 7 and atmospheric valve 9 again, abstraction pool 10,11 by pipeline each and outlet valve 13 again, 14 join, outlet valve 13 is connected in to be connected to after the quartz elastic capillary tube 17 in connector 15 and the cloudy power device heater 19 collects test tube 20, and same outlet valve 14 is connected to be connected to after the quartz elastic capillary tube 18 in the resistance gauge heater 19 by connector 16 again collects test tube 21.
Its workflow is as follows:
CO
2Liquid CO in the steel cylinder
2In stop valve 3 input high-pressure pumps 4, close stop valve 3, make high-pressure pump 4 reach the pressure and temp of setting, open stop valve 5 and stop valve 7, liquid CO
2Be input to the abstraction pool 10 that sample is housed through four-way connection 6, open outlet valve 13 and extract, its extraction product through after connector 16 and resistance gauge 17 decompressions, is collected product, excessive CO again in the test tube 20 that solvent is housed
2Gas emptying after extraction finishes, is closed stop valve 5, and stop valve 13 is opened stop valve 8 and made abstraction pool 10 be depressured to normal pressure, adorns the sample extraction then again.
Also can extract, at this moment can open stop valve 9 and make CO with the 2nd stream
2Be transported to the abstraction pool 11 unlatching outlet valves 14 that sample is housed and extract, extraction product is collected product in the test tube 21 that solvent is housed after 18 step-downs of connector 15 resistance gauges.
By Fig. 3, in the abstraction instrument casing, there is an installing plate 22 at the middle part, electric component is housed behind the plate, insulation actuating doors 28 is housed before the plate, in abstraction pool heating furnace case 12 is arranged, abstraction pool 10,11 usefulness screws are fixed in the stove case 12, the right side is a resistance gauge calandria 19, and extraction product is collected test tube 20,21 usefulness clips are fixed on the instrument right plate, and quartzy resistance tube one end that has muff inserts test tube 20, in 21 the collection solvent, panel lower-left side is the stop valve of stream control, wherein each access port valve 5 of four-way union 6 two ends and outlet valve 7, two termination inlet valves 13 in addition, outlet valve 14, with atmospheric valve 9, there is temperature controller 24 panel 29 lower right sides, abstraction pool temperature display device 25 and resistance gauge temperature indicator window 26, resistance gauge temperature controller 27.
By Fig. 4, abstraction pool 10,11 has a cylindrical tube 28, and all there is pin thread at two ends, and nut 29 is fixed on the pipe end, and the centre accompanies high pressure resistant, high-temperature seal ring 49 is fixed a filter 31 with primary screw 30 again.
By Fig. 5, right part in the stove case 12, motor 32 is fixed on the fixed body 33, and fan 34 is housed on the motor shaft, a wire netting 35 is erect at stove case middle part, wire netting 35 upper right sides are equipped with heater strip 36, and the lower-left end also is equipped with heater strip, and the right lower quadrant of net is equipped with RTD 37, stove case 12 left parts are erect a fixed head 38 are installed, horizontal support plate 39 is fixed on the fixed head 38, and 2 chucks 40 are housed on the horizontal support plate, and abstraction pool 10,11 just is inserted in the chuck 40.
By Fig. 6,2 heating aluminium blocks 41 are housed in the casing 50, RTD 42 and heating wire 43 are contained between two heating aluminium blocks 41.The heating aluminium block can be opened, in order to quartz elasticity straight tube resistance gauge to be installed.
By Fig. 7, lamp chuck 43 is fixed between the upper mounted plate 44 upper and lower fixed heads 45, and test tube 20,21 is contained in the chuck 43, the outlet connecting plate 46 because of heavy stone used as an anchor on the right plate 48 of casing 47.
By Fig. 8, a side of temperature controller has digital display window 51 and digital setting apparatus 52, and opposite side is equipped with cooling fan 53, and the middle part is two bar printing wiring boards 54, and its Circuits System will be narrated in Fig. 9, Figure 10.
Figure 10 is the circuit diagram of supercritical fluid extraction instrument.
℃ resistance of thermometric RTD is 100 Ω, and its two ends are with Rt(+) and Rt(-) expression, the thermometric bridge circuit is made up of resistance R 1, R2, R3, R4 and Rt, by-power supply of 15V power supply, make it produce the normal temperature output signal of positive polarity.Pre-amplifier is by operational amplifier u1B, capacitor C 1, and resistance R 6 is formed, and mainly the output signal of bridge circuit is amplified, and to adapt to the requirement of relatively controlling and showing, its output some is connected to the temperature signal amplifier input terminal.
Summing amplifier is by resistance R 6, R7, and capacitor C 2 and operational amplifier u2A form, and mainly realizes the reversed polarity superposition of design temperature signal and actual temperature signal, its difference through more than 200 times amplification after, promote the PID ratio again, integration, differential amplifier circuit.
The PID amplifier is by operational amplifier u2B, capacitor C 5 resistance C9 capacitor C 4, resistance R 8 and capacitor C 3 form the input 5 of operational amplifier u2B and the output 7 of amplifier u2B joins with a capacitor C 5 and end resistance R 7 and that get an electric shock the road, common port 6 and the capacitor C 3 of operational amplifier u2B, and an end of an end of capacitor C 5 resistance R 9 parallel connections and 8 parallel connections of capacitor C 4 resistance R joins, the effect of PID amplifier is to the difference signal completed percentage, and integration, differential amplify, and improves the performance of temperature control.
High frequency filter is by resistance R 10, R11, and capacitor C 6 is formed, and the end of R10 is parallel to operational amplifier u2B output 7 again.Be mainly used in filtering integrator various high frequencies in the past in holding together signal.
The ramp voltage integrator is by operational amplifier u3A, u3B, resistance R 19, R20, R21, R22, triode Q2 capacitor C 11 resistance 15 compositions such as grade, produce thus-ramp voltage of 5V, improve the performance and the precision of its control temperature, the output of ramp voltage generator is connected to an input of integrator.
Temperature setting device is made up of binary system toggle switch and corresponding electrode resistance, and to produce the signal that adapts with temperature control prime amplification voltage signal, it is powered from-15 volts, the electrode resistance of individual position dial-up is respectively 6M Ω, 3M Ω, 1.5M Ω, 750K Ω, the electrode resistance of ten dial-ups is 600K Ω, 300K Ω, 150K Ω, 75K Ω, the power resistance of hundred dial-ups is 60K Ω, 30K Ω, and the output of temperature setting device is connected to the summing amplifier input.
Integrator is by operational amplifier u4B, and compositions such as capacitor C 7 resistance R 12 and triode Q1 are mainly used in superposition and integration two groups of signals from PID amplifier and ramp generator, and its output drives the triode Q1 that is used to add thermal control.
Drive circuit is partly mainly by triode Q1, resistance R 12, R13 forms, and the base stage of resistance R 13 1 ends and triode Q1 is joined, the emitter stage connecting resistance R13 of triode Q1 connects+the 15V power supply again, and the emitter and collector of triode Q1 respectively is connected in the input of solid-state relay SSR1 again.
Triode Q1 conducting, the light emitting diode both end voltage of solid-state relay SSR1 is extinguished by bypass, makes solid-state relay be in off-state, otherwise, when triode Q1 ends, solid-state relay SSR1 is just closed, thus in the heating period triode Q1 is ended, and in heating period not, can make triode Q1 conducting, solid-state relay is integrated photoelectric isolating device, and its control end is controlled by suitable d. c. voltage signal, this voltage have or not the break-make that is determining solid-state relay.
Holding circuit is by triode Q3, relay K 1, diode D4; operational amplifier u5A; u5B, diode D2, D3, resistance R 24, R25, R26, R27 and diode D1; resistance R 14, R16 form; this circuit guarantees to remove the possibility that causes temperature control, realizes multiple safeguard protection, for example protection that oversteps the extreme limit of temperature; the protection that RTD is opened circuit, and the protection of RTD one end ground connection.
Heater adopts internal heat type to make pottery and throws off restraint the insulation heater, and is small-sized bar-shaped, 220V, 75 watts.
The temperature signal amplifier is by operational amplifier u1A, inductance L 1, and capacitor C 9, resistance R 17, R18, capacitor C 10 or the like is formed, and it amplifies actual temperature, and is shown in instrument.
Overheat protector is that 5 pin of operational amplifier u5B are just become by negative value the current potential of common point when temperature surpasses the set upper limit temperature.
The output of u5B becomes positive saturation value by negative saturation value, makes triode Q3 conducting through current-limiting resistance R27, and relay K 1 is cut off the normally-closed contact of control heater with regard to adhesive, and temperature is descended because of not heating.
The RTD short-circuit protection is that operational amplifier u1B output is about-2 volts; 6 pin of operational amplifier u4B become negative potential through resistance R 14 and diode D1, and operational amplifier u4B is output as on the occasion of, triode Q1 conducting; solid-state relay cuts off, and heating installation power supply equally also disconnects.
RTD Rt(+) ground protection is that 6 pin by operational amplifier u1B are negative value; u1B is tending towards negative saturated output, makes operational amplifier u4B produce just saturated output through diode D1 resistance R 14, thereby makes triode Q1 conducting; solid-state relay also cuts off, and heater is outage just.
RTD Rt(-) ground protection is under normal condition, and the 2 pin current potentials of operational amplifier u5A for just, at this moment become negatively than 3 pin again, and output also is positive saturation value, so triode Q3 turn-on relay K1 adhesive, heating installation power supply just is cut off.
During test, adopting antioxidant is that Jia Baji removes (the pure product of import) BHT, and Irganox 168,1076, and 3114,1010 samples are to be expected in vain by polyethylene, adds that 0.1% antioxidant is mixing to form; Extractant is a carbon dioxide, and using solvent in test tube is dioxane.