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).
Specification, price list, and operating instructions for a combustion vessel and associated calorimetric equipment.
| Identifier | ExFiles\Box 93\1\ scan0169 | |
| Date | 1st March 1931 guessed | |
| [Page 6] 6 A 5474. Silica Crucible . . . . . . . . . . £ 0 3 0 A 5475. Platinum Crucible, about 0.25 oz. . . . . . . at current market rate. A 5476. Platinum Ignition Wire, varies . . . . . . yard £ 0 2 0 A 5477. Nichrome Ignition Wire . . . . . . . reel 0 1 9 A 5478. Cylinder of Oxygen, 20 cu. feet, with folding key . . . . £ 2 10 0 A 5478A. Oxygen, refill for Cylinder A 5478 . . . . . £ 0 7 6 A 5479. Coir Cover, for Cylinder A 5478 . . . . . £ 0 6 0 A 5480. Ignition Battery, 4 volt, 20 amp. hours, glass container, in crate with handle . . . . £ 1 2 9 A 5481. Benzoic Acid, of known calorific value for determining water equivalent 1 oz. bottle £ 0 3 6 A 5482. Naphthalene, of known calorific value for determining water equivalent 1 oz. bottle £ 0 0 9 A 5483. Gelatine Capsules for burning highly volatile liquids . . . dozen £ 0 5 6 A 5484. Series Resistance for ignition from mains, for any specified voltage up to 250, comprising adjustable rheostat, fuses, switch, connecting plug and socket, all mounted on insulating panel . . . . . . £ 3 0 0 A 5485. Measuring Flask, 1000 ml., unstoppered . . . . . £ 0 3 3 EXPERIMENTAL NOTES. Complete instructions for the determination of the calorific value of solids, liquids and gases are supplied with each instrument. To assemble the vessel the washer D' (see illustration of section of Bomb, p. 3) and the screwed sleeve C' are slipped over the cap B' which is then placed on the bench. The charge and the ignition wire are arranged in the crucible E and the tube A is gently screwed into position. If the combustion is required to take place in the presence of water, this is now introduced by a pipette. The head B fitted with the washer D is dropped into position in the tube A and the sleeve C is gently screwed home. The fine adjustment valve is now connected to the oxygen cylinder and the gauge to the inlet I of the bomb. The valve is opened slowly and the bomb charged with oxygen until the gauge reads 25 atmospheres. At this stage the bomb becomes sealed automatically. The tube connection to the bomb is now removed and replaced by the small screwed plug to prevent water entering the valve in the bomb head. The lifting handle is now screwed into the head and the bomb placed within the ring provided on the base of the calorimeter. This one movement (1) makes the electrical connection, (2) assures that the bomb is correctly centred and (3) prevents its slipping and breaking the thermometer. The measured quantity of water is now poured into the calorimeter and the lids and the thermometer placed in position. For the method of using the Improved Pellet Press, please see page 4. [Page 3] 3 Some of the older forms of combustion vessels (bombs), particularly that of Berthelot, are conspicuously good considering the materials available at the time they were designed. Fundamental alterations in design, however, are now desirable so that full use may be made of the valuable properties of both stainless steel and rubber. Few, if any, of the features of the older vessels have been retained in the present apparatus. It has been regarded as essential to secure:— (a) Assembly by hand (that is, without spanner), (b) low water equivalent and high temperature rise, and (c) easy accessibility for cleaning. SPECIFICATION OF COMBUSTION VESSEL. The body A, of the bomb, is a stainless steel tube machined from the solid metal. It is screwed internally for a short distance at both ends, where, in addition, small shoulders are formed. The lower end is sealed by a rubber washer D', inserted between a flanged cap B' and a screwed sleeve C'. The cap B' carries the ignition pillars and crucible support, which, being short, are rigid and strong. The pillar carrying the crucible support is insulated from the cap B' by a bush and by mica washers and makes contact with a spring fixed to the bottom of the calorimeter as shown in illustration A 5462. The upper end is sealed in a similar manner by a washer, cap and sleeve, D, B, and C respectively. The upper cap carries a screwed and riffled tube O, which is held in a gland and used for carrying off the gaseous products of combustion. This exit is sealed, while a determination is in progress, by screwing O down on to a seating in the cap by means of a small key. The inlet valve T is of the Schrader type, has proved to be thoroughly practicable in this new application, and is easily replaceable. Connection is made to the oxygen cylinder at the screwed inlet I, the path of the gas being through the valve T, and along a horizontal duct into the annular groove RR turned in the wall of the bomb. From here, the gas enters the interior V of the bomb, in a cylindrical stream down the sides of the vessel via the space FF, thus avoiding any risk of disturbance of the charge in the crucible E.{Mr Elliott - Chief Engineer} The caps B and B' are free to move axially in the sleeves C and C'. By reason of the internal shoulders on the wall of the bomb they cannot move inwards, but the pressure of the gas on these caps forces them outwards in opposite directions, compressing the washers D and D' and thereby completing the sealing. The lifting handle shown in the illustration A 5460, screws into the upper cap and is used to insert the bomb into and remove it from the water calorimeter. AUXILIARY EQUIPMENT. The combustion vessel may be used with any suitable form of calorimeter and stirring system. The standard auxiliary equipment as here described is, however, strongly recommended on the grounds both of efficiency and of convenience. The Calorimeter (see top left-hand side of Fig. A 5460) consists of two cylindrical copper vessels of different diameters, connected by tubes near the top and bottom. In the smaller tube is fitted a stirrer having three... [Image Caption] A 5462.—Section of Combustion Vessel, showing also spring contact on base of calorimeter. | ||