Hydro Draft Tube Gate Hoist System Design
This 52.2 MW hydropower facility has three vertical turbine-generator units and is located on a lake in the southeastern United States. There are two existing draft tubes for which gates are used to dewater any one of the three turbines. In the past, a Whirley crane was used to install gates when unit dewatering was required. The Whirley crane is red-tagged Out of Service.
The goal of the project was to design a new dedicated hoist system at the powerhouse tailrace that can install the gates for any one of the three units. After the investigation, however, the owner decided to proceed with a new gantry crane and fixed hoist to run on a new rail system. The new hoist was designed to have enough capacity to lift one gate at a time, along with a lifting beam, while maintaining an adequate safety factor. The lifting beam also included an automatic latching system so that one hoist can install both gates at the bottom of the gate slot.
Bergmann provided the following services:
- Observation of existing conditions.
- Assessment of existing gate lifting system and operations.
- Recommendations for a new gate lifting system (i.e., hoist, supporting structure, lifting beam with an automatic latching mechanism)
- Recommendations for four new gates and modifications to two existing gates and dogging device to work with the new lifting system.
- Recommendations for electrical modifications and a new festoon system to provide power to the new lifting system.
- Recommendations for mobile crane size needed to install the new gates and gantry crane.
- Engineering and design to prepare Issue for Construction drawings and specifications for the recommendations.
