One-Way Surge Tank
A one-way surge tank is a relatively small conventional surge tank, with a check valve in the connecting pipe, or riser, that only allows flow out of the tank. The tank water level is maintained by an altitude valve bypassing the check valve. The tank is located at the high point to supply water and prevent water-column separation. However, one-way tanks provide no upsurge protection to the system because no flow is allowed back into the tank. Wherever there is a possibility of freezing, surge tanks may require insulation or heating.
On sewerage forcemains, special consideration should be given to:
- The design of the check valve at the riser to protect against debris or jamming.
- Careful pump restart procedures following a power failure.
- Cost of refilling this tank with drinking water (to avoid odors).
- A chamber may be required to enclose the tank.
- A sanitary sewer may be required to drain liquid overtopping the tank.