Limited access makes prison installation difficult

Spirax Sarco's ability to deal with difficult installations was recently put to the test by a contract to supply and fit a new boiler feedtank at HM Prison Shotts in Lanarkshire.

Spirax Sarco's ability to deal with difficult installations was recently put to the test by a contract to supply and fit a new boiler feedtank at HM Prison Shotts in Lanarkshire.

Awkward access meant that the new stainless- steel feedtank had to be supplied in sections and welded together on site.

The tank, measuring 3 x 3 x 2m, was supplied with a full set of ancillary equipment including a flash condensing deaerator head and steam injection system.

"We needed to replace two mild steel storage tanks that were corroded, leaking and probably passing lumps of rust into the boiler feed pumps", explains Steven Starritt, Maintenance Manager at the prison.

"Access was very difficult with existing beams preventing the tank being supplied completely prefabricated.

With the new tank we are using less treatment chemicals and the feedwater temperature is now constant.

The previous tanks were oversized for the existing system and the feedwater would cool in the tanks before being supplied to the boiler.

The overall efficiency of the system has improved".

In a separate contract, a Spirax Sarco 500kW steam-to-water plate heat exchanger system is feeding a domestic hot water storage tank for the prison and accommodation.

The system, incorporating pressure reducing and isolating valves, and a condensate recovery system, has replaced two calorifiers that were failing to meet demand.

"At peak times we were getting water at only 45C instead of the required 55C", Starritt explains.

"The use of the plate heat exchanger and a buffer storage vessel has ensured a continuous supply of hot water and a recovery time of 10min for a 10C drop in system temperature.

With a higher constant temperature, the system is less susceptible to bacteria growth".

A further benefit of the heat exchanger system, says Starritt, is the elimination of the time-consuming work needed every 24 months to strip out the calorifier heating coils for insurance inspection.

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