GB200150A - Improvements in or relating to vacuum steam heating systems - Google Patents

Abstract

200,150. Wade, H., (Nash Engineering Co.). March 10, 1922. Pumping machines and apparatus, controlling and regulating.-A water and air pumping system has a receiving tank for air and water, a pump for withdrawing air from the receiver and a second pump for withdrawing water; the operation of the pumps may be controlled by means governed by the pressure and amount of water in the receiver. The return pipes 10 from the heating system &c. discharge through a strainer 11 into the upper part of the receiver 12, the flow being controlled by valves 13, 14 In the form shown two pumping sets are employed each driven by an electric motor 47. The inlet of each of the air pumps is connected by pipes 22, 24 to the header 19 and then by the pipe 18 to the top of the tank. The inlet of each water pump is connected to a header 27 and then by a pipe 28 to one end of the receiver at a slight distance above the bottom and valves 29, 30 in the header control the flow to the pumps. The air from the pumps is discharged from the pipe 35 into the atmosphere after passing through separators 33, 40 for collecting any water from the air discharge. The water from the pumps is discharged through the header 42 and pipe 43 into the boiler. Check valves 44 prevent the return of water to the pumps and stop valves 45 are also provided. A pipe 49 supplies water to keep constant the supply in the air pumps; the quantity supplied is controlled by the orifice 103 of the plug 51, Fig 8 at the end of the connection 50 of the pipe 49. The motors 47 are controlled by switches 53, 60 the latter of which is operated by a diaphragm under the influence of the air pressure in the receiver. while the former is operated by a float 54 in accordance with the quantity of water in the receiver. One of the pumping units is shown in Figs. 5 and 6. The shaft 73 carries the impeller for each pump, the water impeller 74 rotating in the casing 75 with an inlet chamber 77 and discharge 79; the air rotor 80 is arranged with a water seal in an elliptical casing 81 having inlet openings 84 on one side and discharge openings 85 on the other side the two sets of openings being arranged at right angles. Air passes into the spaces between the rotor blades from the inlets 84 and as the impeller rotates these spaces become smaller since water surface approaches the hub thereby forcing the air through the openings 85. The water that escapes with the air is released through the pipe 49 or through the port 88 at the side of the water pump. In operation the returns from the pipes 10 flow into the tank 12 and the water flows through the pipe 49. Later the water flows through the pipe 28 to the centrifugal pump. The float 54 then closes the switch 53 and starts the motors 47. The water pumps discharge water to supply the boiler and the air pumps exhaust air from the receiver. If the water reaches the required level while the air pump is still operating the water pump becomes air bound and requires practically no power. When the air pressure falls to a. predetermined value, the diaphragm switch 60 is operated to stop the pumps. In a modification the diaphragm for operating the switch is arranged near the bottom of the tank so that it is controlled by both air and water pressure.