Miura EX Gas/Oil Series High Pressure Steam Boilers

Miura is known world-wide for their commitment to protecting the environment and their innovative and efficient boiler designs. Their EX Gas/Oil Series High Pressure Steam Boiler is the most versatile industrial steam boiler in the world.

The EX design minimizes carryover and produces dry 99+% saturated steam in less than 5 minutes from a cold start. Faster start-up means less fuel used, greater savings, and more responsible use of precious natural resources.

  • Dual fuel fired: Natural Gas, Propane or #2 Fuel Oil
  • High pressure options available (300 MAWP, 250 MAWP or 170 MAWP)
  • Hot water boilers are available depending on models (refer to the catalog for the hot water boilers for details)
  • NOx rating is available as low as 30ppm depending on model

EX Series Model Design

The MIURA EX Series design consists of rows of vertical tubes sandwiched between two rectangular headers. Both headers are encased in a castable refractory with only the tubes exposed to flame and/or combustion gases.

The upper header is attached to the lower header only by the tubes. As the tubes expand and contract, the headers float up and down accordingly.

This ’floating header’ concept greatly reduces stress and allows for the use of cold feedwater without the fear of significant thermal shock. The ’leaky tube’ problems associated with firetube and bent watertube designs have been eliminated.

Ultra Compact Design Saves Space and Costs

Miura’s EX Series boilers occupy 33% less floor space than typical firetubes, and do not require tube pull space. Compact design means much smaller radiation losses and larger fuel savings.

Full Steam Output In Less Than 5 Minutes

Floating headers mean fast start-up. MIURA boilers produce fast steam in less than 5 minutes from a cold start-up. Standard firetubes require 1 to 1.5 hour start-up times. Miura’s unique design yields significant time and fuel savings.

Dry Steam

The MIURA EX design minimizes carryover and produces dry 99+% saturated steam through a 3-stage process:

  • Initial separation in the tubes
  • Second separation in the upper header and baffle plate
  • Final separation in the cyclone separator

Early Warning Scale Monitor

Scale is a problem all boilers have to deal with. Scale forms when boiler feedwater is not properly treated. Advanced scale formation acts as an insulator; only an eggshell thickness of scale results in a 10% efficiency loss, higher fuel bills and possible damage to the boiler system.

As standard equipment, all Miura EX models are equipped with a thermocouple attached directly to a tube. Should scale begin to form, the Miura boiler will alert the operator – allowing the operator to trace and repair the source of the water hardness. The scale can be removed to restore the boiler to its original efficiencies – saving tens of thousands of dollars in wasted fuel and repair bills.

Unbeatable In-Service Efficiencies

Miura’s computer-aided design results in optimal heating surface transfer with minimal water content for fuel-to-steam efficiencies of 85%. Typical firetube designs can deliver up to 83% fuel-to-steam efficiencies. However, in actual use, MIURA averages 10 to 40% fuel savings over standard firetube designs. How does a 2% difference in fuel-to-steam efficiencies translate into a 10 to 40% ACTUAL FUEL SAVINGS? Contact your local Miura representative for details.

EX-100EX-150EX-200EX-250EXN-300 [6][7]EX-300
Utilization Horsepower100 HP150 HP200 HP250 HP300 HP300 BHP
Maximum Pressure [1]170 PSIG MAWP, 150 PSIG Maximum Operating
Equivalent Output [2]3,450 LB/HR5,175 LB/HR6,900 LB/HR8,625 LB/HR10,350 LB/HR10,350 LB/HR
Heat Output3,348,000 BTU/HR5,022,000 BTU/HR6,695,000 BTU/HR8,369,000 BTU/HR10,050,000 BTU/HR10,040,000 BTU/HR
Efficiency (fuel to steam) [3]85% (80% without Economizer)86% (81% without Economizer))
Heating Surface Area196 FT²323 FT²323 FT²389 FT²499 FT²515 FT²
Operational Weight7,250 LBS11,500 LBS11,500 LBS17,850 LBS18,000 LBS18,000 LBS
Shipping Weight7,500 LBS7,700 LBS8,340 LBS8,990 LBS11,010 LBS11,010 LBS
Width81 in.91 in.91 in.94 in.99 in.99 in.
Length109 in.130 in.130 in.136 in.142 in.142 in.
Height99 in.120 in.120 in.146 in.157 in.166 in.
Combustion SystemProprietary Forced Draft, Step Fired Modulation Hi-Low-Off
Ignition SystemElectric Spark Ignited, Interrupted Gas Pilot
Power Supply208, 230, 460, 575V, 3 phase, 60Hz
Max. Electrical Consumption13.35 KVA (14.2 for Oil)24.5 KVA (25.4 for Oil)27.5 KVA (28.5 for Oil)32.3 KVA (34.3 for Oil)35.4 KVA (37.3 for Oil)35.4 KVA (37.3 for Oil)
Fuel Type [4]Natural Gas or Propane (3-5 PSIG), No. 2 Oil
Gas Consumption [5]3,920 SCFH5,880 SCFH7,850 SCFH9,810 SCFH11,780 SCFH11,670 SCFH
No. 2 Oil28.1 GAL/HR42.2 GAL/HR56.3 GAL/HR68.7 GAL/HR84.5 GAL/HR82.3 GAL/HR
Gas Supply Pressure3-5 PSIG (Natural Gas or Propane)
Main Steam Outlet Valve2 in.3 in.3 in.4 in.4 in.4 in.
Safety Valve Outlet [8]One 2 in.One 2 1/2 in.One 2 1/2 in.One 2 1/2 in.Two 2 1/2 in.Two 2 1/2 in.
Main Water Inlet1 in.1 in.1 in.1 1/4 in.1 1/4 in.1 1/2 in.
Fuel Gas Inlet2 in.2 in.2 in.2 1/2 in.2 1/2 in.2 1/2 in.
Fuel Oil Inlet3/4 in.3/4 in.3/4 in.3/4 in.3/4 in.3/4 in.
Automatic Surface BlowdownOne 3/8 in.One 3/8 in.One 3/8 in.Two 3/8 in.Two 3/8 in.Two 3/8 in.
Manual BlowdownTwo 1 in.Two 1 in.Two 1 in.Two 1 in.One 1 in. & One 1 1/4 in.One 1 in. & One 1 1/4 in.
Chimney Diameter (ID)14 in.20 in.20 in.20 in.26 in.20 in.
Flame DetectorUltraviolet Flame Eye Sensor
Pressure ControlAdjustable Pressure Transducer and Switch
Liquid Volume ControlElectric Conductivity Type
Overheat ProtectionLow Water Cut Off & Thermocouple


  • Optional EXH-SGO Series at 250 Psig MAWP, 225 Psig maximum operating
  • Equivalent output calculated from and at 212°F (100°C) feed water at 212°F (100°C) steam.
  • Thermal efficiencies are based on high heating values of fuels at 68°F (20°C) feed water.
  • UL and c-UL approved for natural gas or propane.
  • Gas consumption based on natural gas with high heating 1004 BTU/SCF.
  • Low water content option available to meet provincial water volume regulations in Canada
  • Low NOx model (EXN300SGOF) available to meet 30ppm NOx
  • Safety valve outlet size may change depending on the pressure setting.

All Miura steam boilers are fully packaged and test fired at factory. Built to meet or exceed UL and ASME standards in U.S.A.; c-UL and B-51 standards in Canada.