Patent GB-927203-A (GB)
Title: Improvements in hot water circulating systems
IPC: F24D3/10
Filed: 1959-07-11
Abstract: 927,203. Hot-water supply systems. C. H. HOARE. Oct. 10, 1960 [July 11, 1959], No. 23895/59. Class 64 (1). In a domestic combined hot-water supply system and space heating system of the indirect type the primary water circulating between a boiler and a vessel in contact with the secondary water is automatically replenished from the bulk secondary water to a level in the vessel determined by the level of an air venting outlet therefrom, the primary water being at all times isolated from the secondary water by an air lock which is maintained by air released from the secondary water during heating, the capacity of this air lock being controlled by an expansionpipe formed with an inverted U-bend or entering a skirted tank to provide an air barrier. In the form shown in Fig. 1 the secondary water is stored in a cylinder A and is supplied thereto from a cistern A1. An open-topped vessel B is disposed within the tank and connected by pipes a, a1 to a boiler, not shown. When the system is filled secondary water overflows into the vessel filling the heating circuit until the water reaches a level in the vessel determined by an air venting outlet pipe C which has a return bend over the cistern, thus providing an air lock in the top of the cylinder which isolates the two systems. The capacity of the air lock is determined by an expansion pipe C1 which also has a return bend over the cistern. Radiators for space heating are connected between pipes a3 and c11 respectively leading from and returning to the pipes C1 and al. In modifications, Figs. 5 and 6, not shown, the vessel B is located externally of the cylinder A and is surrounded by a jacket connected with the cylinder or forms a jacket around an inner container connected with the cylinder. In a further modification, Fig. 7, not shown, the vent pipe C opens into a tank within the cylinder, the tank having a depending skirt which surrounds the top of the vessel B to provide the air lock. In a further modification, Fig. 3, the water in the storage cylinder A is heated by contact with the walls of a open-topped cylinder B having a double-walled skirt portion extending downwardly from a domed bottom b. The cylinder is connected into a primary circuit including a boiler, not shown, by pipes a, a<SP>1</SP>, the water being heated in the cylinder passing up through the space b6 inside the skirt to discharge through an opening b7 and passing upwardly in contact with the outer wall of the skirt. To prevent the mixing of the water in the primary circuit with that in the cylinder an inverted cylinder B1 is mounted over and adjacent the top of the cylinder B which has a serrated upper edge, an expansion pipe C2 extending from a level within the latter below the upper edge through the top of the cylinder B1 and having an inverted, U-bend disposed thereabove. In operation, the primary and secondary systems are filled through a pipe a2, water overflowing into the cylinder B when it reaches the top thereof to fill the primary system until the pipe C2 seals to prevent further level rise in the cylinder, the secondary system then being completely filled. When heating commences air released from the primary water maintains the volume of the air lock and hence the primary water level in the cylinder B, expansion water flowing into the reservoir. Furthermore, a second air lock is maintained in the bend of pipe C2 by air released from the water in the reservoir this air passing upwardly through a bell-mouth pipe C6 to enter the bend. Subsequently the air locks prevent the mixing of the secondary and primary water. When the systems cool the primary water level is maintained by an overflow from the reservoir into the cylinder B. Specification 644,962 is referred to.