Liquid Distributors for Thermostatic Expansion Valves (type 69G)

The 69G distributes refrigerant liquid from the thermostatic expansion valve to the individual sections of the evaporator.

Note!
The thermostatic expansion valve must have external pressure equalization.

Selection of liquid distributor

The following data must be known:
1. Refrigerant
2. Evaporator capacity
3. Evaporating temperature
4. Number of evaporator sections
5. Expansion valve type

It is then possible to determine:
I. Size of distributor tubes
The capacity of the individual distributor tube is calculated by dividing the total evaporator

Capacity by the number of uniform evaporator sectionsIt is recommended that distributor tubes be sized for a pressure drop of approx. 0.5 bar. Table I, which gives the capacities for different tube
Sizes, is based on this pressure drop. For tube lengths exceeding 1 m, tubes should be selected

With larger diameters than indicated in table I. The figure shows the relation between evaporator capacity Qe, refrigerant, tube diameter, evaporating temperature te and pressure drop p for 1 m distributor tubes. The tube diameter can then be found in table I or the graph below.
Sizing should be based on the average capacity of the evaporator. A sufficiently uni- form distribution can be expected at capacities of between 40% and 125% of the values given in table I.