WALTER KIDDE TRANSFER UNIT

The Walter Kidde unit, like the SC-5 ^is designed and manufactured expressly for the purpose of transferring carbon dioxide in its liquid form from one cylinder to another. The unit is supplied complete with the necessary adapters, recharging valves, safety discs and bushings, nuts, bolts, and washers needed to make connections to the cylinders and minor adjustments to the unit. Pump Models 4211 and 4211-1 are driven by a three-fourths horsepower motor and are equipped with a safety switch and lead fitted with a plug. Three-prong plugs and three-wire leads should be substituted for the ordinary two-wire and twoprong arrangement. Pump Models 4306 and 4306-1 are driven by a single-cylinder, four-cycle, three-fourths horsepower, air-cooled engine. Figure 3-3 illustrates the Walter Kidde electric recharge unit, Model 4211.

COMPONENTS

The carbon dioxide transfer unit (figure 3-3) consists of the following major components: compressor assembly (5), running gear assembly

Figure 3-3.\Walter Kidde Electric CO2 Transfer Unit,

Model 4211.

(4), motor (7), multibreaker (l), power cable (9), and base (8). The only difference between the models lies in the type of compressor supplied; however, the compressors are interchangeable between the models. A spare parts kit, recharging transfer fittings, and charging fittings are used in conjunction with the units.

Motor

The repulsion start induction single-phase motor, shown in figure 3-3, is a 115- to 230-volt, 60-cycle, three-fourths horsepower unit. It operates at 1750 rpm and draws 9.8 amperes at 115 volts. This type of motor supplies very high starting torque with a very low starting current. In starting, the motor has repulsion motor characteristics; but at running speeds, it functions as an induction motor since the motor windings are automatically short-circuited and the brushes are lifted from the commutator when the operating speed is approached.

Multibreaker

The thermal, magnetic multibreaker, shown in figure 3-3, is a two-pole, 115-volt ac, 20-ampere unit installed to protect the power circuit from overloads. In addition, it acts as a manual ON/OFF switch for the operation of the transfer unit. If the multibreaker trips because of a power overload, you may reset it by placing the switch first to OFF and then to ON.

Compressor Assembly, Model 4211 Carbon Dioxide Transfer Unit

This unit, shown in figure 3-4, is a two-stage, single-action, displacement-type compressor. The running gear assembly actuates the unit and transfers the liquid carbon dioxide from the supply cylinder to the cylinder being recharged. The lower section consists of a cylinder body (6), plunger (7), molded metallic packing (8), spacer (10), and plunger guide (9). The plunger (7), which acts as a piston and transfers the liquid carbon dioxide, is connected to the crosshead of the running gear assembly. The upper section of the unit consists of a cylinder head (2) with an intake and outlet port, an intake valve (11), a discharge valve disc (4), and a discharge valve cap (l). A safety disc and washer, located in the cylinder head behind the safety disc plug (13), releases the ^{carbon dioxide from the compressor when the} pressure exceeds the 2650- to 3000-psi range.

Figure 3-4.\Compressor Assembly, Model 4211 Carbon Dioxide Transfer Unit.

Figure 3-5.\Compressor Assembly, Model 4211-1 Carbon Dioxide Transfer Unit.

Compressor Assembly, Model 4211-1 Carbon Dioxide Transfer Unit

This unit, shown in figure 3-5, is functionally similar to the compressor described for the 4211 unit. The lower section of the compressor

Figure 3-6.\Running Gear Assembly.

consists of a cylinder body (6), plunger (7), molded metallic packing (8), spacer (10), and plunger guide (9). The upper section of the unit consists of a cylinder head (3) with an inlet and outlet port, an inlet valve check (11), an outlet valve check (4), and a discharge valve cap (l). A safety disc and washer located in the cylinder head behind the safety disc plug (13) releases the carbon dioxide from the compressor when the pressure exceeds the 2650- to 3000-psi range.

Running Gear Assembly

The running gear assembly, shown in figure 3-6, consists of the crankcase (4), crosshead guide (l), crosshead (2), connecting rod (3), and the crankshaft (7) riding in two roller bearings (6 and 12) mounted in the end plates (5 and 11). Mechanical connection to the motor is made by means of a gear keyed to the crankshaft and meshed with the driving gear on the motor shaft. The two gears are enclosed by the gear guard (6, figure 3-3). Access to the oil reservoir within the crankcase is obtained through the oil filler cap (9). The crankcase can be drained by removing the drain plug (8).