From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Directions for testing the physical and chemical properties of paper.
| Identifier | ExFiles\Box 24\2\ Scan241 | |
| Date | 30th January 1923 guessed | |
| 662 DIRECTIONS FOR THE STUDY OF This value is defined as the bursting strength of the paper. The bursting strength of the paper shall be measured at ten positions equally spaced diagonally across a test-piece one foot long and the full width of the roll, when the paper is submitted in a roll, and at ten positions equally spaced diagonally across a sheet, when the paper is submitted in sheets. The maximum, minimum and mean values of the bursting strength shall be stated. The direction in which the paper commences to break with respect to the length of the paper shall be noted. For the method of determining the direction of “length” and “width” of paper when supplied in sheets, see Appendix. A suitable apparatus for carrying out the test is shown in Fig. 1.* 6. TEARING STRENGTH. The paper shall be conditioned in accordance with Clause 1 before the tearing strength test is carried out. The resistance to tearing shall be proved by the load required to tear the paper commencing from a hole 3/32 inch diameter punched out of the paper. The position of the hole and application of the load shall be as shown in Fig. 2. The size of each separate specimen tested shall be 6 inches square. (a) Three tests shall be made with the tear in the direction of the length of the paper. This shall be called the “Length Tear Test.” (b) Three tests shall be made with the tear across the width of the paper. This shall be called the “Width Tear Test.” For the method of determining the direction of “length” and “width” of paper when supplied in sheets, see Appendix. The method of carrying out the tearing test shall be as follows :— Prepare the paper specimen as shown in Fig. 2. Swing the inverted “L” piece to the right. Place the paper in position, the punched hole being at the angle of the “L” piece as indicated. Screw the “L” piece down. Bend over the cut piece “A” (1/8 in.), shown dotted, and attach grip device—needle or clip—and secure to lower portion of balance. Rotate the winding gear with steady movement at a rate of approximately 12 inches per minute until the 6-inch length is torn through. (A motor drive is recommended.) Watch the balance and average the slightly varying values of the pull observed. The maximum, minimum and mean values of the “length” and “width” tearing strengths respectively shall be stated. 7. POROSITY. The paper shall be conditioned in accordance with Clause 1 before the porosity test is carried out. * Fig. 1 is not reproduced here. The porosity of the paper shall be determined by means of the following apparatus, which shall be assembled as shown in Fig. 3. Glass burette graduated 0 to 100 cc (length of 100 cc graduations approximately 22 inches) and fitted with a stopcock at top. Two metal clamping discs having 1 inch recess in one and 1 inch hole in the other. The inner side of each disc shall be faced with sheet rubber 1/32 inch thick. Aspirator bottle approximately 300 cc and 2 5/8 inches diameter fitted with a rubber tube connection at bottom. Three feet of rubber tubing, internal diameter 3/16 inch and external diameter 7/16 inch. Ring stand approximately 4 feet high. The test shall be carried out as follows :— Open the stopcock of the burette, and place the aspirator bottle in the upper support. The bottle shall contain sufficient water, and the upper support shall be so adjusted that when the surface of the water in the burette coincides with the zero mark the depth of the water in the bottle is about one inch. A strip of paper 2 1/4 inches wide shall be cut from the roll or sheet. The length of the strip shall be equal to the full width of the roll or sheet. The strip of paper shall be clamped between the rubber-faced metal discs, the stopcock closed and the bottle lowered until the surface of the water is 24 inches below the zero mark of the burette. The stopcock shall then be opened for 15 seconds, which shall be measured by means of a stop-watch or similar instrument. Immediately after the stopcock has been closed the bottle shall be raised until the surface of the water in the bottle is in the same horizontal plane as that in the burette. The water level in the burette shall then be noted. This reading, which shows the number of cubic cm of air drawn into the burette through the paper, shall be taken as the porosity number of the paper. The porosity of the paper shall be measured at 10-points, 5 inches apart, located across the width of the roll or sheet. The maximum, minimum and mean values of the porosity number shall be stated. When the width of the roll or sheet is insufficient to enable 10 tests to be made on one strip, two or more strips shall be tested. For the method of determining the direction of “length” and “width” of paper when supplied in sheets, see Appendix. 8. CHEMICAL TESTS. (a) Moisture Loss on Drying at 212° F.{Mr Friese} (100° C.). The paper shall be conditioned in accordance with Clause 1 before the test for moisture loss is carried out. Approximately 25 grammes of the sample shall be weighed after conditioning, dried at a temperature of 212° F.{Mr Friese} (100° C.) for 3 hours and then re-weighed in an artificially dried atmosphere. The moisture loss shall be computed as a percentage of the weight of the sample after conditioning and before drying. (b) Test for Acidity and Alkalinity. The test for acidity and alkalinity shall be carried out as follows :— | ||