The working system of a water treatment plant is a very delicate process that any material could put at risk. To prevent elements from entering the interior of the installation and compromising the system, a clamshell grab/bucket is used in the screen chamber.
What is the role of clamshell grabs in water treatment plants?
The clamshell grab is a mechanism that is located at the starting point of the treatment plant, in the screen chamber, with one objective: to remove all the solid elements that it transports to an external container.
For this task, there are different types of shells specialised in gripping, dehydration and extraction for each specific material:
- Stones
- Sand
- Sludge
- Silt
- Scale
How does it work? Is it automatic or is an operator required?
Although there are situations in which the operation of the clamshell grab may be automated, it is most common for an operator to run it from the ground.
To do this, the operator uses a keypad that allows for the operation of the mechanism each time the elements are to be extracted.
At that time, the device's shells are submerged in the water and the extraction process begins.
For this, the shells have a synchronising bar that allows the airtight closure of the lips with a continuous, uniform and symmetrical force.
Given that during this process the liquid is extracted to achieve the dehydration of the elements, the valves have small slotted holes that allow for drainage.
How do the shells work when operated by the operator?
As its name suggests, each clamshell grab has two shells made of electrically welded sheet material, reinforced with brackets inside to maximise its effectiveness.
These tools work by means of an electro-hydraulic drive that opens and closes the shells that it uses to press and dehydrate the waste found in the water treatment plant.
The model used in water treatment processes is powered by two reinforced hydraulic cylinders that act as a joint to perform the necessary movements.
To ensure that everything works correctly, these cylinders are mounted on bronze casings and side washers at the rear, with a threaded dredger at the front.
In addition, to guarantee its durability, the lips are reinforced with 450 HB hardness anti-wear material that guarantees a much longer useful life
How to choose the correct clamshell bucket for a water treatment plant?
When choosing this tool, it is very important to take into account two key factors:
- The capacity of the grab. Depending on the plant’s inlet flow, it is better to choose an equipment with more or less volume capacity
- Specialisation of the treatment plant. Clamshell grabs used for these purposes must be specifically designed to work in water — they are known as the amphibious type.
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