The location and the actual installation of sensing bulb is very important. He must be in good thermal contact with the evaporator, Fig. 5-32. The ball must be installed on top of the suction line. The liquid in the bulb is close to the suction line as shown in Fig. 5-32A. For fixing the lamp on the vertical line absorption, capillary tubes, lamp must always enter from the top of the flask. He must never enter bottom.
The lamp should not be affected by air or liquid cooling. It should be wrapped in insulation, both in Special insulation forms are available so that only the suction line temperature affects the ball. Plastic tapes can also be used for this purpose.
Copper belts and not rusting machines, screws and nuts should be used for attaching the lamp on the suction line. The ball must have excellent thermal contact with the suction line. Communication must be clean and tight. Both suction line and tubes should be cleaned with steel wool, before Assembly.
Suction line carries mainly refrigerant evaporates.
However, there will be some drops of liquid refrigerant and oil. Fig. 5-33 illustrates the conditions inside the suction line, particularly at sites requiring large diameter line. On Fig. 5-33A, refrigerant vapor and a few drops of the liquid flowing through a fairly large diameter of the suction line. Due to the large diameter and the speed of evaporation of the coolant will be slow at times. Drops of liquid refrigerant and oil will settle to the bottom line. In the suction area in Fig. 5-33B less. As a result, the speed of evaporation of the coolant will be higher than in Fig. 5-33A. This means less oil separation and liquid refrigerant from flowing pairs. Inside the pipe will be fairly evenly coated with oil. Suction line in Fig. 5-33s is displayed in a vertical position. In this position, there will be no division drops from the refrigerant vapor. However, the oil evenly coat the inside of the suction line.
The evaporation temperature of the refrigerant and the drops of the liquid refrigerant will be a few degrees colder than the surface of the suction line. This is due to the insulating qualities of oil that coats the inside of the suction line.
Sensitive lamp for big suction line should be located near the bottom row, and not at the top, because drops of liquid refrigerant, as a rule, separately from flowing vapour. In addition, the oil has an insulating effect. Recommended position lamp (at large suction) is shown in Fig. 5-33D. Some of the sensing bulb corrugated or uneven along ensure the double contact and help align the sensing bulb from the surface of the suction line.
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