CS199092B1 - Helium densitometer with chromatographic detection - Google Patents

Description

The invention relates to a helium densitizer and to a chroeetogrefic detection intended to target the real huetos of porous materials and polymers.

Doeud used pycnometers not spreading the real huetot of porous eetoriels! to target either liquid or helium gas.

The actual density of the porous materials is measured by determining the volume of liquid above the catalyst in a bulk or weight manner. The advantage of determining Jo is its high volume determination accuracy. The disadvantage is, on the other hand, the large preenoet, distortion of the results due to the difficulty of pre-emitting samples and never the possibility of dissolution in the medium used and, in the case of polymeric substances, the possibility of swelling of polymers. To measure the actual density, s uses 1 opposite procedure, ie weighing the sample in air and in the liquid to be measured and defined density. The second method uses inert helium to determine the actual density, when it is drunk again by the jam of the pycnometer filled with the catalyst, not by a maneuvering process consisting in compressing the helium by a defined volume while aiming for the clowns. The advantage of this arrangement is perfect lnertneat helium with respect to the aiming substrate and damping accuracy 1. The disadvantage is the necessity to work with a vacuum at a pressure of about 0.1 Pa and possible 1 mercury and a high level of aiming.

The abovementioned non-decomposition is not a helium densimeter and chromatographic detection according to

199 092

199 092 invented, consisting of a U-shaped pycnometer having a four-way inlet valve and a four-way toggle valve connected in a field, the four-way toggle valve connected to one helium circuit and the other to the pycnometer, and the four-way toggle valve connected and a chromatographic circuit consisting of a capillary volume and heat-conducting the entire and in the second position serially and through this chromatographic circuit. The measuring medium is a pair of Inert gases β of different thermal conductivity, or. helium and ergon, respectively helium and duel, wherein argon and duel, respectively, is the carrier inert gas of the chromatographic circuit. The impregnated valve serves to release the pycnometer with helium under dynamic conditions. The chromatographic circuit is composed of an elliptical water-level detector and a capacitive volume. The method utilizes a large difference in thermal conductivity of the selected pair of flax gases, which o measures in the thermal hydrofoil cell and the capacity volume is designed to reduce the high helium concentration in the carrier gas so that it can be accurately indicated in the thermal hydrofluence cell. volumes of permanent gases, e.g. 30 to 50 ml, as opposed to conventional chromatographic procedures.

The helium denzltometer arrangement and chromatographic detection retains all the advantages of the helium denzltometer and manomatic detection. The advantage of the proposed arrangement is simple determination on a commercial chromatograph and an additional device according to the invention.

An exemplary embodiment of a helium densimeter and chromatographic detection is schematically shown in FIG. 1, while FIG. 2 illustrates the helium densimeter used according to 3 ' and Brula and manomatic detection for comparison. The novelty of the solution and the effect achieved by the helium donor engine according to the invention results best from the mutual comparison of these devices.

Helium denzltomotr and manomatricko detection shown in FIG. 2, and COST own pyknomotru 1 and the volume ⁱⁿ Py | ⁽ⁿ * ^{Nía for a} * bou associated two okalibrovaných volumes: a first volume V2 7 and a second volume V ₃ 8, and she system It is separated by a shut-off valve 9 from a U-manometer 10 provided with a degassing valve 11 connected to the valve 12 and a helium reservoir 13. The apparatus is further provided with a buffer tank 14 for mercury and an auxiliary U-manometer 15.

After inserting the analyzed material into the pycnometer X o, the sample was degassed by the degassing valve 11. then the degassing valve 11 closes and infuses aa helium inlet valve 12 to a selected pressure of 20 kPa indicated by the U-manometer 15 and adjusts aa mercury to volume. and measure the aa pressure p ₃ on the U-manometer 10 then o and increase the mercury level to the second volume line 7 and the pycnometer 1 in the same way, and measure the pressures p ₂ and P 1. 3o, if the volume of the pycnometer 8 and the material to be analyzed Vj, the first volume of 7 V ₂ and the second volume of 8 V ₃ , according to Boyl's law, for thormoatated space (V _t ♦ v ₂ + V ₃ ) p ₃ - (V _t + V ₂ ). p ₂ ( ^V 1 * v ₂ ) p ₂ - in _t . _Pl < ^v i ♦ V ₂ ♦ V ₃ ) p ₃ - in _t . _Pl

From the above equations α, Vj is calculated as the average of three meshes.

199 092

The actual density ^ _e j ( _Ut ·· is calculated by the equation:

^J Vz ^V pykn - ^V 1 who Gy _z y sample weight, ^V pykn ^ob J · * empty pycnometer and

Vj is the volume of the pycnometer and the material to be analyzed, ie. volume of space above the catalyst in a pycnometer not filled with helium.

Na obf. 1 shows a helium-densimeter with chromatographic detection according to the invention, consisting of a p-shaped O-shaped pycnometer 1.0 having a four-way sweep valve 2 and a four-way sweep valve 3 in series, the four-sweep sweep valve 2 being fed by a single helium circuit and a second circuit on The pycnometer 1 and the four-way switch valve 3 are connected by the pycnometer 1 in one position in parallel with the chromatographic circuit consisting of the capacitive volume 4 and the thermal conductive whole 5 and in the second position in series with the chromatographic circuit consisting of the capacitive circuit 4 and the thermal conductive all 5.

The measuring medium is a pair of inert gases having different thermal conductivities, for example helium and argon, helium and nitrogen, with argon or nitrogen being the charged inert gas of the chromatogreflile circuit. The helium dontitometer for chromatographic detection according to the invention works quite differently from the procedure for manometric detection.

The function of the device is a direct measurement of the volume V * of the chromatograph. Using the quadruple voltage valve 2 and the pycnoaotr 1 and the lukewarm analyzed material, flushes the helium when the switch valve 3 is not in the parallel position of the pycnometer 1 and the chromatographic circuit, then closes the pycnometer 1 by turning the pressure valve 2 and chromatograph with a capacity volume of 4 and a topically conductive whole 5 to perform thermally conductive volume detection V _± . The same operation ae then performs an empty pycnometer 1.

Velikost β-II Aj size of the recording of the chromatographic signal (chromatographic peak) for the pycnometer pad and the measured flight load

A pycnometer for _two unfilled, then the true density ^ _e | _<ut confused the relation ^V pykn ' ^A even where Gy _z is the weight of the filling measured by the flight and ^V pykn is the volume of the pycnometer without the filling.

The use of a helium densepheter with a manometric indication where the volume of the solid phase is measured from the pressure difference and a high-pressure sensitive manometer, usually O-type, is required, and if the level is read, static adsorption devices requiring a vacuum device and an achievable pressure of about 1 mPa to completely fail the pycnometer.

The helium densimeter with the chromatographic indication according to the invention measures directly the volume of helium in the pycnometer - in a blank test without a sample - and at the same time the volume of the pycnometer common and the pore volume. The differentiation of these volumes gives a direct discovery? solid féze. The helium densitometry meter of the present invention does not require the installation of an evacuation device, but operates with a pair of inert gases and achieves a perfect purge by merely replacing helium with argon and vice versa, the device operating under isobaric conditions. The values need not be expressed in absolute volume units, but in relative chromatographic peaks (A _in Ag) for a given conceal volume that has been previously measured.

The invention is useful in determining the true solid-state density of porous materials and polymers, which is particularly necessary in heterogeneous catalysis, but the insulating properties of materials, surface properties and other physical properties of solids.

Claims (1)

Helium densimeter for chromatographic detection, characterized in that it consists of a U-shaped pycnometer 1 having a four-way non-flowing valve 2 connected to a four-way reversing valve 3 in which the four-way flowing vont11 is connected with one circuit to helium and the other to the pycnometer 1. and a pycnoeotr 1 in the iodine position in parallel and a chromatographic circuit consisting of a capacitance 4 and a thermal hydrotermination of the whole 5 and in a second position in series with this chromatographic circuit, with a pair of inert gases β of different thermal conductivity, e.g. and argon, helium and dualk and the like, of which argon or duo, respectively, is the carrier inert gas of the chromatographic circuit.