Patent GB-448693-A (GB)
Title: Improvements in or relating to the maintenance of temperature in sterilizers for goods enclosed in bottles or other containers
IPC: A23L3/04
Filed: 1934-11-07
Abstract: 448,693. Sterilizing bottled &c. goods. WEBSTER, R. W., and WEBSTER, A. H., 224, Nether Street, Finchley, London. Nov. 7, 1934, No. 32038. [Class 49] [See also Group XXIX] In sterilizers of the kind in which the goods are enclosed in bottles or other containers which are conveyed in baskets &c. mounted on chains through the sterilizing chamber which is closed at the entrance and exit by a water seal, the chamber being heated by steam or other vapour under pressure and the height of the water seal being dependent on the pressure of the steam &c. to be maintained in the chamber, the rise and fall of the water level in the water seal is utilized to operate the valve, switch or other device for controlling the admission of heating medium to the chamber. The heating medium usually employed is steam under pressure supplied to the chamber or generated therein, e.g. by steam, gas, or electrically heated radiators. In one form, Fig. 8, a float c is situated in the chamber at the lower water seal level d and is attached to one end of a pivoted lever g, the other end of which is connected by a rod h to a lever h<3> pivotally mounted at h<4> on the sterilizer and operatively connected to an air valve h<5> which controls the air supply by which the steam valve is actuated. In another form, a float a, c is provided in each compartment of the water seal or within tanks 6, 7, Fig. 6, one connected with each compartment C, D by a pipe 8, 9. The float a is carried at one end of a pivoted lever e, the other end of which is connected by a rod f to one end f<1>, Fig. 2, of a lever i to the other end n of which is attached a rod, cable or other transmission means o connected to the member controlling the supply of heating medium. The lever i is pivoted at its centre to one end of a lever k, pivoted at m on the sterilizer casing, the other end of which is connected by a rod h to the centre of a lever g to which the float c is attached. The arms of lever i are each equal in length to the arm of lever k to which they are attached and are half the length of the other arm of lever k. The arm of lever e to which rod f is attached is half the length of the other arm. The lever system is such that when both floats a, c simultaneously rise or fall by an equal amount, caused for example by alteration of the levels of the water seal by change of displacement due to variation of the load on the conveyer, the pressure in the chamber being unaltered, the end n of lever i will not be displaced and the transmission means o will not be actuated. If, however, the floats are moved otherwise, e.g. in opposite directions, by reduction of pressure in the chamber caused by a fall in temperature without any change in displacement, the means o will be actuated. The steam valve 25, Fig. 6, through which steam is supplied to the heaters is normally maintained on its seat by air pressure on a diaphragm in a chamber 27 to which compressed air is supplied through a pipe 29, a valve 28 and a pipe 30. In a fall of pressure in the sterilizing chamber, the lever system actuates through rods 13, 14 and against a spring 31, a trip valve 15 exhausting the compressed air to atmosphere and causing opening of steam valve 25. To prevent the level of the water seal falling too low, a blow-off valve 24 is provided which is actuated through a bell-crank 23 and a rod 22 by a guide 19 acted on by lever arm g when float c falls too low. The lever system may be replaced by a differential gear, Fig. 5, consisting of racks q, r pivoted to the arms e, g of floats a, c and in mesh with pinions s, t which are keyed, each with a bevel wheel u, v, on sleeves freely mounted on a shaft w. Bevel pinions x, y freely mounted on shafts z, z<1> carried on a sleeve 2 secured to the shaft w are in mesh with the bevel wheels u, v. On shaft w is fixed a control cam 3 on which rides the roller 4 of a lever 5 for operating the heat supply means. Specification 377,890 is referred to.