Dump Tube

Function

The dump tube is used in combination with a steam converting valve. Following pressure and temperature reduction within the valve, the bypassed steam is finally discharged through the dump tube via a multitude of outlet bores into the condenser or the turbine exhaust piping. This design is applicable for both high-pressure installations directly connected to the condenser/exhaust line (e.g., waste-to-energy plants, biomass power plants, etc.) and large-scale power stations, including coal-fired or combined cycle gas and steam power plants with varying pressure stages (IP, LP).

The dump tube acts as the final pressure reduction stage upstream of the vacuum-operated condenser. Utilizing it as the final, supercritical pressure reduction stage allows for an optimized number of stages within the valve as well as an optimized outlet nominal size.

When applying dump tubes, a distinction is made between two installation principles:

Water-cooled condenser: Dump Tube installed inside the condenser
Air-cooled condenser: Dump Tube installed in the turbine exhaust line

Design

The design of the dump tubes is highly versatile and fully customizable.

A distinction is made between single-stage and multi-stage dump tubes, as well as between various models featuring different connection types—such as the "torispherical head" connection—and customized layouts of the steam outlet bores.

Welland strictly utilizes erosion-resistant materials for the dump tube, such as 13CrMo4-5/SA182F12 or 11CrMo-9-10/SA182F22.

Benefits

Reduction of the valve outlet nominal size
Reduction of the pressure reduction stages within the valve
Low investment costs due to optimized structural design of the steam conditioning valve (DUV) and dump tube
The diameter and length of the piping between the steam converting valve (DUV) and the condenser can be reduced and shortened (saving both cost and space).
The steam entering the condenser is directed by the outlet bores within the dump tube in such a way that damage to the condenser cooling tubes is prevented.