Our congratulations go to Matt and all of the other solutions that were submitted by Members in 2022.
The Problem
What was the problem that you experienced?
Manual removal of rag from sewage pump stations using rakes in combination with a jet hose to cut up the rag was a very slow, physically demanding and high risk activity which would often result in rag and debris being transferred to the treatment plant and potentially cause problems there.
Removal of rag was very slow hard work with significant risk needing to be managed because operators often had to reach over railing to access rag under edges of the sump. It relied on physical effort to drag rag from pump and snag points often several meters into a sump. Rakes only allowed capture of debris down to a limited size and made lifting large rag balls almost impossible. Large rag balls had to be gradually pulled apart resulting is many lost pieces and frustratingly slow progress.
How did the problem impact you or your work situation?
Manual handling risks including soft tissue injuries due to using the rake.
A rake is not an effective tool as it cuts through rag which then falls apart. This resulted in a very tedious and extended period of physical activity leaning over rails pulling on the long shaft of the rake. The process often resulted in many smaller rags that were difficult to capture or were sucked through to other equipment or filters.
How long had the problem been occurring?
Rags balls and ragging have been increasing with the increased use of wipes. While there have been some iterations to rakes, they have generally been the standard tool for many years.
The Solution
How did you come up with the solution?
Matt Holz and Vere Story started investigating better ways of working. They looked at a range of options to grab the rag and lift it mechanically. They drew initial
designs on paper and discussed it with coordinators and managers. Their manager, Brendan Hannigan, discussed the idea with the TasWater Innovation Team and linked in Vere and Matt to take action on it.
The Innovation Team undertook an assessment and then worked with a manufacturer to create a prototype. The first prototype was reviewed by Matt and Vere together with the Safety Officer, Greg Slore. A revised design included a better clamping action on the jaws and a bigger volume. It was important that the volume did not become too large limiting access to tight spaces and creating too heavy a lift.
The safety team reviewed the design, undertook necessary checks and issued directives on use before the first trial. The second prototype was trialled with further modifications of the scissor action provided by the Safety Officer.
Who helped work on the solution?
- Vere Story – Operator
- Brendan Hannigan – Manager
- David Holmes – Innovation Team Lead
- Greg Slore – Safety Officer
Describe the solution.
The Claw. The claw has clamps that grab the rag without cutting or breaking it, and as the claw is lifted up, the scissor action causes the clamp to grab tighter as the weight is taken up. This way, the rag is lifted as a large wad. The claw can be operated on the lift arm of service utes or larger trucks.
One operator holds a rope that opens the jaws – a later design has a holding mechanism that can be pulled to releases the jaws to close rather than the operator holding them open. The jaws also enable the collection of smaller debris and gravel that was impossible to capture previously. The original rake or a pole can be used to push the claw under ledges and position it on a rag ball. Rag that is torn off very large rag balls is captured and held fast in the jaws, unlike with the rake.
The claw has also been very effective at grabbing tree roots which are hard to hold fast and pull out.
How has it helped you at work?
Operators don’t have to enter the pump well or use a rake to remove rag. This eliminates risks associated with confined space entry and manual handling. It is much quicker and much less physically demanding than the rake. Less rag is dislodged and sucked back into pumps or lost on filters. Gravel and other debris that may arise in combined sewer /stormwater systems can be captured. Roots can be held firmly and pulled out or cut with the action of the jaws.
Suggest improvements, if time or financial limitations were not a factor.
Smaller and larger versions would be useful for different situations. As noted above there is a recent addition that holds the jaws open until they need to be deployed.
Any other comments.
Care needs to be taken to clearly see what is captured in the jaws, particularly where there are potentially cables or other features in the sump. The claw can be released if an unintended item is captured.