Document LKQo8JOO8pMnJjZwjOZdGdK3w

Specialties, Heating G. M. Davis Regulator Company 407 MILWAUKEE AVE., CHICAGO, ILL. Since 1875 Manufacturers of Better Valve Specialties Davis Piston Type Pressure Regulator (Any service pressure) Davis Back Pressure Valve Davis Piston Type Regulator For reducing high pressure steam down to any service pressure. Patented inner valve design in sures proper regulation regardless of velocity. Lever gives visible operation and makes hand testing possible. Oil dash pot insures steady action. Sizes % to 14". Davis Back Pressure Valve The Original semi-balanced exhaust line valve for * maintaining a given back pressure. Has double seated piston disc--operates noiselessly--requires comparatively small counterweight, patented disc and seat construction prevents sticking. May be used horizontally or vertically. Sizes 2 to 30". Angle valves made to order. Davis Steam Trap Double cone shaped- balanced valves give con tinuous flow--unusually large capacity--handle any pressure--take care of widely fluctuating load. All vital parts are renewable and quite accessible. Sizes ii to 3".'' Other Davis Valves A 64 page catalog showing a number of pressure regulating devices, not here illustrated will be sent on request. Tell us about your special problems in pressure control--we may be able to be of service. ! 296 Davis Steam Trap Specialties, Heating Donnelly Systems Company 9 Murray Street NEW YORK, N. Y. TEMPERATURE CONTROL BY REGULATION OF SUPPLY AND DISTRIBUTION OF STEAM OR VAPOR Impulse Check Valves, Thermo-Differential Valves and other Specialties for One and Two* pipe Vapor and Vacuum Return Line Systems- The practical and theoretical experience of 37 years has developed the difference in pressure between the branch steam and return lines of one-half pound is always maintained. Donnelly Sys Impulse Check Valve tems and the Donnelly Speci alties. The entire operative mechanism of the Im pulse Valve is enclosed in a heavy removable The general theory of design and con tube which is inserted trol of the steam circulation in all Don in a standard valve nelly Systems.is based upon the recog body and the valves nized principle that in small systems there are guaranteed for five Thermo-Differentid are, for short runs and for a limited years. Valve number of automatic return valve de vices, no appreciable differences or losses in pressure. In other words, small sys tems have always proved simpler and more satisfactory in operation than target systems. The Thermo-Differential Valve, used in Vacuum Return Line Systems, is con structed as shown. It is made with a standard safety valve body and has a restricted seat which is proportioned to the capacity of the valve. The valve disc Therefore all Donnelly gravity and is provided with an impact surface, as in vacuum return line plants are divided into the Impulse Valve, and with a cup-shaped groups of convenient and restricted size. portion for holding the weights, together The former are provided with a Thermo- with a central rod which acts as a guide Float Air Valve and the latter with a for the vaporizing fluid thermostat. The Thermo-Differential Valve for each group. opening in the bottom of the valve is intended as a cleanout and should be The early recognition of this principle led to the design of the Impulse Check Valve, which is used at the return out-' lets of all radiators and coils in all Don provided with a nipple and cap. A small leakage opening is provided in the seat so that the system will drain when shut down. nelly. Systems, preventing any water or steam from entering the radiator from the A Thermo-Differential Valve is installed return piping. in each branch return so that no water, air or steam can pass into the main return It is an Automatic Needle Valve, the without being properly regulated in pres size of the orifice through the seat being I sure and flow. properly proportioned to the pipe size and to the rated capacity of the valve. The normal operation of the valve is the same in all systems, the weight over area of the disc and the size of the orifice being such that a complete discharge of the air and water is at all timeseffected and a constant Send for information on latest develop ments in Temperature Control. Catalogs and bulletins describing our specialties and their application will be gladly furnished on request. 297