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).
Product information and specimen determination for the Griffin-Sutton Bomb Calorimeter.
| Identifier | ExFiles\Box 93\1\ scan0168 | |
| Date | 27th June 1935 guessed | |
| 7 THE GRIFFIN-SUTTON BOMB CALORIMETER Patent Applied for A 5460.—Complete Outfit (without thermometer). A combustion bomb which can be closed by hand and which attains an accuracy of 0·1 per cent. on the calorific value and 0·05 and 0·1 per cent. respectively on the carbon and the sulphur contents. Advantages claimed for the method of construction. 1. A new type of sealing by internal pressure which enables the ends to be screwed in lightly by the fingers and as easily removed after the pressure has been released. 2. Even distribution of the incoming oxygen round the internal wall of the bomb, thus completely avoiding disturbance of the charge. 3. Unusually large area of contact between outer wall of bomb and surrounding water owing to long length and small diameter of the bomb. 4. Clean straight cylindrical shape ensuring against water pockets and making the interior easily accessible for cleaning. 5. Very efficient Calorimeter and stirring arrangements. A new and convenient form of pellet press (Registered Design) is shown in the illustration (bottom left hand corner). It is so made that the ignition wire may be inserted in the sample before compression. After compression, the wire is thus firmly embedded in the moulded pellet and ignition failures reduced to a minimum. Specimen Determination. The following data gives a typical set of readings. Other methods of procedure and calculation may, of course, be employed if desired:— Nature of Fuel .. .. .. .. .. .. Coal (Anthracite B). Weight of Silica Crucible and Fuel .. .. .. .. .. 2·894 grams. Weight of Silica Crucible .. .. .. .. .. .. 1·952 „ Weight of Fuel .. .. .. .. .. .. .. 0·942 „ Weight of water added = 1200 grams. Total Water Equivalent of system = 1932 „ Time (mins). Temperature Reading °C. Temperature Change °C. Remarks 0 19·130 .. .. 1 19·133 + ·003 2 19·138 + ·005 Rate of change of temperature before ignition = 0·004° C. per min. 3 19·142 + ·004 4 19·146 + ·004 5 19·150 + ·004 6 .. .. Sample ignited. 12 23·227 + 4·077 .. 14 23·240 + ·013 15 23·240 ·000 Maximum temperature attained. 16 23·240 ·000 18 23·229 — ·011 Rate of change of temperature after ignition = 0·006° C per min. 20 23·217 — ·012 22 23·205 — ·012 A simple method of applying the necessary corrections for radiation has been evolved and gives a result differing by not more than 1 in 2000 from that obtained by application of the various standard formulae. It is sufficient to extrapolate the initial and final temperature curves to a time which is found for apparatus of this type and size to be 1½ mins. after firing. From the table above, the initial radiation correction before firing is ·004° C. per min.; 7½ mins. after observations have begun (i.e., 1½ mins. after firing), the temperature would therefore have been 19·150 + 2.5 × ·004 = 19·160° C. had the charge not been fired. | ||