Heat Transferring Embossed Surface
Mechanically embossed spiral ribs on the inside of the tube not only provides increased surface area, but also leads to a complex gas flow with a boundary layer producing a separation/reattachment phenomenon.

This reattachment action substantially improves heat transfer. With this enhanced tube design, the heat transfer rate is 85% greater than a plain fire tube. Cost savings of up to 20% on the entire boiler package can be obtained with the use of enhanced spiral ribbed tubes.

BOILER DESIGN: Modified: Thru-the-door 2-Pass Scotch Marine Firetube design with stress relieving “HURST Wetback” construction. Pressure designs available for steam and hot water are: 30-125 HP. 15 PSI max. (STEAM) 30-125 HP. 60 PSI max. (HOT WATER)

Section IV
Factory assembled with trim, tested, ASME code, UL, and CSD-1 standards. STEAM MODEL TRIM: Safety relief valve, operating pressure control, high limit pressure control with manual reset, steam pressure gauge with syphon, combination pump control and low water cut-off with gauge glass assembly and drain valve, auxiliary low water cut-off with manual reset.

HOT WATER MODEL TRIM: Safety relief valve, operating temperature control, high limit temperature control with manual reset, combination pressure & temperature gauge, low water cut-off control with manual reset.

BURNER: Matched UL listed “forced draft” power burners with factory prepiped, wired and tested fuel configurations for natural gas, propane (LP) gas, No. 2 (diesel) oil, or combination of both gas/oil.

Dry back boilers are subject to deteriorating rear refractory, leaking baffles, leaking door seals, and often found with a heat-stressed rear tube sheet. Fragile refractory baffling and door seals will require continuous monitoring, maintenance, and replacement, costing thousands of dollars in materials and specialized labor costs over the life of the boiler. In addition, broken baffles and leaking seals will short-circuit the boiler’s gas flow, causing high stack temperatures and lowering efficiency until repairs can be made.

This can bring your production process to a costly halt. All of those frustrating problems have been designed out of the Hurst Series LPX Wet back. It has a full wet back radiant heat transfer area that promotes superior internal water circulation and rapid heat absorption, rear tube sheet, and allows tubes to expand and contract at its own rate without tube sheet stress. The only rear refractory is a manway plug which allows access to the furnace for inspection.