Reference cell assembly

Procedure to prepare the reference cell assembly including the closed cell... 

It is always indispensable for almost all self-heating chemicals, irrespective of whether they are of the TD type or of the AC type, to determine the or the T, of each run by inserting the reference cell assembly into the adiabatic jacket in the adiabatic self-heating process recorder, or into the aluminium block bath in the isothermal storage testing device, prior to the insertion of the sample cell... 

The procedure to prepare the reference cell assembly including the closed cell is exhibited below by means of a series of photographs. In this connection, the closed cell used to prepare the reference cell assembly is needless to say of the same type and size as that used to prepare the sample cell assembly. 

Figure 26. This photograph shows a general view of the reference cell assembly including the glass flange tube combined with the empty closed cell by means of the cap nut. The assembly is held in the vertical position by means of a clamp of a stand. It is possible to slide the stand horizontally on the laboratory desk. On the other hand, a laboratory jack, at the center of the upper plate of which a pedestal is stuck, is fixed on the desk. The position of the stand is then adjusted horizontally in order that the assembly may be aligned vertically with the pedestal. A pack of cigarettes is put on the laboratory jack, and by the side of the assembly, to show the relative size of the closed cell. The cell measures 1.4 cm in outside diameter and about 3 cm in length in other words, it is about half the size of a thumb.

Figure 28. The empty reference cell assembly is set on the pedestal by raising the laboratory jack.

Figure 33. The reference cell assembly is finally completed by tightening the cap nut.

Figure 34. After having lowered again the laboratory jack a little, a fairly small vibrator is applied to the base of the closed cell in order that silica powder confined in the cell may come closely in contact with the glass capillary tube. The reference cell assembly is now ready for the adiabatic sclf-hcating test.

Figure 35. The reference cell assembly has, in fact, been prepared at the rear side of the adiabatic self-healing process recorder.

Figure 36. fhe reference cell assembly thus prepared is inserted into the adiabatic jacket set in the preheated air bath of the recorder. 

Figure 37. Insertion of the reference cell assembly into the adiabatic jacket has now been finished.

The two pens of the two-pen strip chart recorder are composed of the temperature or T pen and the temperature difference or A Tj,ff pen. After the reference cell assembly has been inserted into the adiabatic jacket set in the air bath, which is now being heated up to the temperature, T the T pen records the... 

The thermal equilibrium state is attained around the reference material confined in the closed cell and inserted into the adiabatic jacket maintained at the nominal T, of the run 2 3 h after the insertion of the reference cell assembly into the jacket. After the thermal equilibrium state has nearly been attained around the reference material, the power supply to the analog D.C. microvoltmeter is switched on in the meantime, the ATdiff pen of the two-pen strip chart recorder is also switched over from short to on . It is then observed that the indicator of the analog D.C. microvoltmeter enters on to the scale span of the meter from the minus side where the condition, A Tdiff= (Tref-holds, and, it comes to stay near the graduation line of zero at the center of the scale span of the meter in the meantime, the A Tjiff pen of the two-pen strip chart recorder also enters on to the strip chart of the two-pen strip chart recorder from the minus side. For the term, the minus side, refer to the paragraph after the following. 

The reference cell assembly is successively taken out of the jacket, and the sample cell assembly including a closed cell, in which a definite quantity of a chemical of the TD type, the volume of which is also about 2 cm, has been confined in the same manner as performed to prepare the reference cell assembly in Subsection 4.5.2, is inserted into the adiabatic jacket. The quantity of a chemical of the TD type tested depends naturally on the specific gravity. 

The thermal equilibrium state is attained around the reference material charged in the open-cup cell and inserted into the adiabatic jacket maintained at the nominal T,. of the run 2 3 h after the insertion of the reference cell assembly into the jacket. After the thermal equilibrium state has nearly been attained around the reference material, the power supply to the analog D.C. 

Figure 76. This is an enlarged view of the reference cell assembly including the empty open-cup cell and the pedestal. The cell is seen to be supported with a thin aluminium washer and two springs and is combined with the ground glass joint at the lower end of the glass vent tube.

Figure 81. The reference cell thus prepared is then combined concentrically and softly with the ground glass joint of the glass vent tube by raising again the laboratoiy jack to constiuet the reference cell assembly in the meantime, the CA thermocouple, covered with a glass capillary tube, to measure the Tr,f, the temperature of an oxidatively-heating substance, or that of a non-volatile chemical of the TD type, is inserted automatically and axially to the longitudinal center of silica of coarse particles charged in the cell.

Further explanations regarding the procedure to prepare the reference cell assembly including the glass vent tube combined with some one of the three kinds of open cells are the same as those given to Figs. 35, 36 and 37 exhibited in Subsection 4.5.3. 

The reference cell assembly is successively taken out of the jacket, and the sample cell assembly including a draft cell, in which a definite quantity of a... 

Insertion of the reference cell assembly into the preheated aluminium block bath in the isothermal storage testing device and the determination of the exact value of TV of the run... 

The reference cell assembly is raised with a pair of fairly large pincers and is inserted carefully down to the bottom of the hole, 23 mm in diameter, 75 mm in depth, bored vertically at the center of the upper surface of the preheated aluminium block bath which is set in the isothermal storage testing device in the meantime, the temperature of the bath is maintained at the T, K of the run throughout every run. 

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