Wastewater application: Hydraulic power units meet pump protection requirements

A wastewater treatment plant contacted DeZurik about a unique pump protection application. This application required eight 30-in. eccentric plug valves with hydraulic actuators to cycle between 5 and 10 s. Two hydraulic power units (HPUs) were needed to operate four valves each.

The HPUs were in a ground-level operations building, and the valves were located many floors below grade. An individual, local control panel for each valve needed to be located near the valve installation. Both the valve and local control panels had to be capable of possible submergence.

In the case of a power loss, an emergency fail position and manual override were required. In addition, the HPU control panel needed to communicate with the plant’s distributed control system (DCS).

The company was selected as the single-source supplier for the valve package and the hydraulic power source because of its capabilities in designing and building systems solutions, combined with the complexity and unique installation requirements of this application.

A customized HPU.

The DeZurik team designed and manufactured the two HPUs to meet the extensive requirements for this project. The hydraulic actuators were sized to exceed the service conditions.

Position indication and manual hydraulic override were supplied as part of the actuation package on the valve. Special attention was required due to the submergence specification.

Design and sizing of the HPU was extensive. As usual, system pressure, flow requirements and pump sizing were all part of the initial design. Then came the design of the emergency fail position capability, accumulator tanks and integration into the HPU system package.

Completing the system design was the control system for the HPU and individual local control panels. Extensive consideration and engineering were essential to meet the submergence requirement of the individual local control panels as well as the HPU requirement to communicate with the DCS.

The DeZurik HydraStorm HPU.

The company has designed and produced numerous HPUs supplied to many industries including mining, power, water, and wastewater treatment to meet specific needs.

DeZurik also manufactures the Hydrastorm HPU in three reservoir sizes and a variety of AC and DC voltages. This versatile unit is said to pack a lot of power in a small, rugged package with variable pressure and flow adjustments.

In addition to supplying hydraulic actuated valves, the HPU company can also supply units as part of a complete system solution.

This white paper was prepared by DeZurik. See more here.