The problem:
In this episode we are going to discuss of the persistent problem of Vertically Suspended Submergible pumps. Despite of its many advantages, most of such pumps suffer of frequent suction strainer chocking. Barring some clean applications most of them are used for pumping out dirty water with lot of suspended debris from sumps. Hence, they get plugged at the suction strainers quite often. Cleaning the suction strainers have always been painful problem.
The issue:
Most of such pumps are situated around plant. Let us list out the issues in attending the cleaning job of the suction strainers.
- VS pump normally needs crane to lift to access its strainer.
- Mobilizing crane for this purpose is cost and time-consuming effort.
- Unlike other pumps, VS pumps requires more manpower to do this simple job, strainer cleaning. To elaborate this point, besides the main technician, crane operator and electrician are additionally required. The discharge line flanges are to be unbolted to facilitate pump lifting. And must be fixed back after the pump is dropped to its position.
The challenge:
Horizontal pumps’ strainers can be attended without disturbing the pumps. Same way, what need to be done for VS pumps such that the strainers can be cleaned without disturbing the pump?
The remedy:
The following modification gives a way out.
The pump’s suction is extended as shown and the strainer is rested upside down.
Whenever the strainer cleaning work is warranted, the strainer can be simply lifted, and cleaning job is performed. Then lowering down to its position completes the job.
The details:
• The strainer is designed to sit on the respective flange without any bolting.
• The strainer flanges are preferably conical as to the ensure concentric positioning.
• The tie-rods guides and ensures the proper positioning of the strainer on to its location.
• Lifting and lowering can simply be done by a chain block or pulled by a utility truck. No need for cranes anymore.
• When cleaning is in process, to ensure safety, the strainer access hole is to be temporarily covered by suitable board.
• Despite of this precaution, if any thing slips into the sump and into the suction port, they are expected to get trapped at the bottom of the T-branch.
• Additionally, a conical strainer can also be included at the suction flange. This should prevent any debris that manages to get into suction line during strainer cleaning process.
Implementation issues:
This modification calls for one-time alteration works at the site.
• Pump’s suction system must be modified to facilitate the strainer’s new position. This calls for additional pipe work with couple of pipe bends.
• Pump access hole and the base frame are to be modified to accept new setup.
Expected benefits:
But for this modification work, there should not be a need for crane mobilization there later, forever. This is one single big saving of cost and time.
After this modification, strainer cleaning work, should requires lesser manpower than earlier.
MTTR - Mean Time To Repair is expected to be grossly reduced.
4 сен 2024
