CHAPTER VI REFRIGERATING SYSTEMS. (Part 6)

The Alercoid Switch cctnsists of a glass tuljc in which are sealed leads of sjjecial material. A cpiantity of mercury makes or breaks the circuit when the tube is tilted. Hermetically sealed within the tube are inert gases which stifle the arc instantly. There is no oxidation or corrosion. The contact is permanently clean and instantaneous in operation. Fig. 28 shows the remote control, flexible tube type. Fig. 29 shows the ])ressure type thermostat. 180 HOUSEHOLD REFRIGERATION This control can be furnished to automatically open or close an electric circuit with a change in temperature. The circuit is controlled directly to the motor or other electric equipment. Ordinary lighting or power current can be run through the control. The operation of this control is very simple. A power ele- ment is expanded automatically by temperature, which in turn, FIG. 29.— PRESSURE TYPE THERMOSTAT. tilts the switch with a snap action. A spring throws the switch in the opposite direction as pressure or temperature decreases. A special feature of the thermostatic power element is its dependability. The operation remains constant and does not change; years of service will not affect its power or sen- sitivity. The power element consists of a seamless metallic bellows, the folds of which are so made that expansion and contraction will not affect the life of the metal. When used thermostati- cally the bellows contain liquids of various boiling points as determined by the desired operating temperatures. REFRIGERATING SYSTEMS 181 Refrigerator Control Switch. — Fig. 30 is a sectional view ot the electric refrigerator control unit made by the Automatic Reclosing Circuit Breaker Company of Columbus, Ohio. The expansion bellows is filled with a freezing solution. When this solution freezes the bellows expand and close the T£/?Al//^m5 coA/r/Fcr D/sc 3f/LLOyVS O/L FIG. 30.— SECTIONAL VIEW OF ELECTRICAL REFRIGERATOR CONTROL. electric circuit by forcing the dish-shaped contact against the two electric terminal inserts. There is no adjustment for temperature as this setting is obtained by changing the proportions of the materials used for making the freezing solution. This design affords a control free from outside adjust- ments and of very simple construction. 182 HOUSEHOLD REFRIGERATION Multiflex Bellows. — Fig. 31 shows the seamless one-piece multiflex metal bellows made by the Bishop & Babcock Sales Compaii}". These bellows are used in many different parts of electrical refrigerating systems, usually in connection with the thermo- stat while some manufacturers use them Uj seal the compres- sor shaft. A — IiisidL- Diameter P. — Outside Diameter. FIG. 31.~SEAMLESS OXE-PIECE MULTIFLE.X METAL i'.EIJJ^WS. Table LXI gives standard sizes of bellows. Wall thick- ness can be supplied for external or internal pressure to 500 pounds per scjuare inch. The Fedders Manufacturing Company oi Buffalo, New York, make ai)pliances for household refrigerating machines. Fig. 32 shows a condenser and receiver unit. The con- denser consists of coils of coi)])er tubing with a special type of copper fins to increase the cooling efficiency. REFRIGERATING SYSTEMS TABLE LXI aTANDAKD BELLOW.s 183 Outside Inside Free No. of Norniul Diameter Diameter Movenioiit Convolutions I.engtli 1" M" M" 18 Us" IM" ^Vx^' 5^6" 16 l-Ke" IH" 1" y^' 18 IM" VA" 11^2" Vs" 18 1^" 1^" 1%" y^" 18 IM" I'Hg" 1^^" ^" 18 2" 2" l^/fe" Ke" 16 2!'i'6" 2W IJ^" y," 14 2M" 2%" 1«^" Ke" 15 2M" w% 2M" M" 18 33^" 43^" 3^" M" 17 25^" 7^" 6K" J^" 10 2M" Fig. 2)C> is a photograph of the expansion vahe which may be used with any of the refrigerants ifi common use in house- hold machines. A change of springs is necessary with very low pressure refrigerants. FIG. 32.— CONDENSER AND RECEIVER UNIT. Fig. 34 is a tubular liquid strainer used in the inlet connec- tion to the expansion valve. A liquid filter, Fig. 35, is used to filter out the small particles of scale or oxide which may accumulate in the refrigerating system. This filter contains two circular pieces of fine meshed screen with wool felt be- tween them. (V 184 HOUSEHOLD REFRIGERATION Fig. 36 shows a typical brine tank. These tanks are made of tinned copper with lock seams. The wall thickness of the copper is .028 inches. These tanks are made in standard sizes FIG. 33.— EXPANSION VALVE. to suit the requirements of the different styles and types refrigerators in use today. FIG. 34.— TUBULAR LIQUID STRAINER. REFRIGERATING SYSTEMS 185 FIG. 35.— A LIQUID FILTER. FIG. 36.— A TYPICAL BRINE TANK.