Venturi distributors 16/6/11 (VK III)

The division of the evaporator into several parallel sections with the same pipe length and the same heat transfer capacity brings advantages where, depending on the required surface, very long evaporator pipes would be needed. The advantage: When connecting long pipe lengths of the same diameter in series, the transfer capacity does not increase in the same proportion as the surface area does with the length of the pipe. The longer path of flow at an increased refrigerant throughput results in a greater loss of pressure. This in turn means an increased gas volume, leading to a reduction in the quantity of refrigerant taken in from the compressor - which ultimately translates into a reduction in cooling capacity. Evaporators are therefore divided into several parallel sections with relatively shorter pipe lengths. The individual sections are fed via a fluid distributor, the task of which is to distribute the refrigerant/vapour mixture from the flow regulator evenly across each of the sections. Since fluid distributors are not themselves regulators, being an auxiliary piece of equipment only, they are not able to adapt the mount of refrigerant being fed through the sections if there is a change in demand (same pipe length, flow resistance, heat transfer capacity, etc.)

Installation

The fluid distributor should be mounted vertically. The distribution pipes must be of the same length. The fluid distributor can be mounted directly to the expansion valve. If a bend in the pipe between the expansion valve and fluid distributor cannot be avoided, then a straight section of pipe needs to be installed between the bend and the fluid distributor. This straight section of pipe must have a length that is at least 7 times that of the pipe diameter.