Boiler Mountings. Boiler mountings are nozzle connections, distance pieces, valves or fittings attached directly to the boiler and are always subjected.

Boiler Mountings

Boiler MountingsBoiler Mountings

Boiler mountings are nozzle Boiler mountings are nozzle connections, distance pieces, connections, distance pieces, valves or fittings attached valves or fittings attached directly to the boiler and are directly to the boiler and are always subjected to boiler always subjected to boiler pressure.pressure.


Boiler valve mountings shall be Boiler valve mountings shall be opened for inspection by a U.S. Coast opened for inspection by a U.S. Coast Guard Inspector every 5 years.Guard Inspector every 5 years.

Boiler mountings, studs and bolting Boiler mountings, studs and bolting shall be removed, inspected and shall be removed, inspected and tested if necessary by a U.S. Coast tested if necessary by a U.S. Coast Guard Marine Inspector every 10 Guard Marine Inspector every 10 years.years.


Watertube boilers must be Watertube boilers must be hydrostatically tested every 5 years in hydrostatically tested every 5 years in the presence of the U.S. Coast Guard the presence of the U.S. Coast Guard at 1¼ times the maximum allowable at 1¼ times the maximum allowable working pressure (MAWP) of the boiler. working pressure (MAWP) of the boiler.

The water used for the hydrostatic test The water used for the hydrostatic test must be no less than 70 ˚F and no must be no less than 70 ˚F and no more than 160 ˚F.more than 160 ˚F.


In the case the boiler has undergone In the case the boiler has undergone major repairs. The boiler must major repairs. The boiler must undergo a hydrostatic test of 1-1/2 undergo a hydrostatic test of 1-1/2 times the maximum allowable times the maximum allowable working pressure of the boiler.working pressure of the boiler.

Main Steam StopMain Steam Stop

Main Steam Stop Valve is a valve Main Steam Stop Valve is a valve connected directly to the boiler or, connected directly to the boiler or, when a superheater is provided, to when a superheater is provided, to the superheater outlet for the the superheater outlet for the purpose of connecting or isolating purpose of connecting or isolating the boiler from the main steam line. the boiler from the main steam line.


On multiple boiler installations a stop On multiple boiler installations a stop check valve must be employed for check valve must be employed for this purpose.this purpose.

If the Main Steam Stop is a 6 inch If the Main Steam Stop is a 6 inch valve or larger the valve must be valve or larger the valve must be equipped with a bypass valve or “run equipped with a bypass valve or “run around”around”


The bypass valve is a small valve The bypass valve is a small valve usually around ¾” to 1” which permits:usually around ¾” to 1” which permits: Warming up the steam line at a slow rateWarming up the steam line at a slow rate Pressurizing the downstream line slowlyPressurizing the downstream line slowly Equalizing the pressure on both sides of the Equalizing the pressure on both sides of the

Main Steam Stop so it is easier to openMain Steam Stop so it is easier to open Permits the combustion control to react to Permits the combustion control to react to

pressure changes without rapid pressure changes without rapid adjustmentsadjustments

Turbo-Generator Steam Turbo-Generator Steam StopStop

The Turbo-Generator Steam Stop The Turbo-Generator Steam Stop Valve is also connected to the Valve is also connected to the superheater outlet. Its purpose is to superheater outlet. Its purpose is to connect or isolate the boiler from the connect or isolate the boiler from the ship service generators. ship service generators.

On multiple boiler installations a stop On multiple boiler installations a stop check valve must be employed for this check valve must be employed for this purpose.purpose.

Auxiliary Steam StopAuxiliary Steam Stop

The Auxiliary Steam Stop Valve. Is The Auxiliary Steam Stop Valve. Is connected directly to the boiler or connected directly to the boiler or desuperheater outlet, if fitted for the desuperheater outlet, if fitted for the purpose of connecting or isolating purpose of connecting or isolating the steam to the auxiliary steam the steam to the auxiliary steam lines. lines.

On multiple boiler installations this On multiple boiler installations this valve must be a stop check valve.valve must be a stop check valve.


Source: Machinery Manual Catalunya Spirit


Main Steam Stop

Auxiliary Steam Stop

Stop Check ValveStop Check Valve

Safety ValvesSafety Valves

Safety Valves are provided for the Safety Valves are provided for the purpose of relieving the boiler purpose of relieving the boiler excessive steam pressure when, for excessive steam pressure when, for some reason, the pressure builds up some reason, the pressure builds up above the safe operating pressure. above the safe operating pressure.

The boiler drum is fitted with two The boiler drum is fitted with two safety valves and the superheater is safety valves and the superheater is provided with one. provided with one.

Superheater Safety ValveSuperheater Safety Valve

The superheater safety valve is The superheater safety valve is placed at the superheater outlet and placed at the superheater outlet and is set to open before the drum safety is set to open before the drum safety valves. valves.

This protects the superheater from This protects the superheater from excessive temperature by insuring a excessive temperature by insuring a steam flow through it.steam flow through it.

Superheater Safety ValveSuperheater Safety Valve

Superheater Safety Valve

Main and Auxiliary Feed Main and Auxiliary Feed StopsStops

The Main and Auxiliary Feed Stop The Main and Auxiliary Feed Stop Valves are installed in the main and Valves are installed in the main and auxiliary feed lines respectively. auxiliary feed lines respectively.

They are used for connecting and They are used for connecting and isolating the feed water lines to and isolating the feed water lines to and from the boiler. from the boiler.


When the boiler is fitted with an When the boiler is fitted with an economizer the auxiliary and main economizer the auxiliary and main feed lines join before the economizer feed lines join before the economizer inlet with the stop valves fitted as inlet with the stop valves fitted as close as possible to the junction point. close as possible to the junction point.

A check valve is then installed on the A check valve is then installed on the outlet of the economizer and is outlet of the economizer and is considered a boiler mounting in lieu of considered a boiler mounting in lieu of the main and auxiliary feed stop valve. the main and auxiliary feed stop valve.


When the economizer is fitted with a When the economizer is fitted with a bypass a stop check shall be bypass a stop check shall be installed in lieu of the check valve. installed in lieu of the check valve.

Should the economizer rupture, this Should the economizer rupture, this check valve will close preventing the check valve will close preventing the steam and water flowing back from steam and water flowing back from the steam and water drum and out of the steam and water drum and out of the economizer.the economizer.





Main Feed Line

Economizer Bypass

Auxiliary Feed Line

Surface and Bottom BlowsSurface and Bottom Blows

Surface and Bottom Blow Valves are Surface and Bottom Blow Valves are connected directly to the boiler for connected directly to the boiler for the purpose of blowing out water, the purpose of blowing out water, floating debris and solids.floating debris and solids.


The surface blow is for removing the The surface blow is for removing the floating impurities from the waters floating impurities from the waters surface.surface.

The bottom blow is for removing The bottom blow is for removing solids and sludge which has solids and sludge which has precipitated out of the boiler water.precipitated out of the boiler water.



Bottom Blow

Surface Blow

Drum VentDrum Vent

The Drum Vent (Air Cock or Drum The Drum Vent (Air Cock or Drum Cock) is a globe valve on the top of Cock) is a globe valve on the top of the steam and water drum. This the steam and water drum. This valve is used to permit the escape of valve is used to permit the escape of air when filling and lighting off a air when filling and lighting off a boiler. It is also used when securing boiler. It is also used when securing or draining the boiler to prevent the or draining the boiler to prevent the formation of a vacuum.formation of a vacuum.

Drum VentDrum VentDrum Vent

Pressure Gauge ValvesPressure Gauge Valves

Pressure Gauge Valves are globe Pressure Gauge Valves are globe valves mounted on the steam and valves mounted on the steam and water drum or other parts of the water drum or other parts of the boiler used to connect or isolate the boiler used to connect or isolate the boiler pressure gauges.boiler pressure gauges.

Gauge Glass Shut Off ValvesGauge Glass Shut Off Valves

The Gauge Glass Shut Off Valves are The Gauge Glass Shut Off Valves are mounted on the top and bottom of mounted on the top and bottom of the gauge glass, they are generally the gauge glass, they are generally angle globe valves arranged to angle globe valves arranged to prevent stoppage by deposits of prevent stoppage by deposits of sediment. sediment.

The bottom shut off valve is provided The bottom shut off valve is provided with a ball check valve. with a ball check valve.

The ball of the check valve in normal The ball of the check valve in normal operation remains on its holder. operation remains on its holder.


In the event of gauge glass breakage In the event of gauge glass breakage the sudden rush of water through the sudden rush of water through bottom connection forces the ball bottom connection forces the ball upward into its seat to prevent upward into its seat to prevent further escape of hot water. further escape of hot water.

Normally the top shut off valve of the Normally the top shut off valve of the gauge glass is not equipped in this gauge glass is not equipped in this manner. manner.


Gauge glass shut off valves are Gauge glass shut off valves are generally equipped with chains to generally equipped with chains to permit shut off from the operating permit shut off from the operating platform. platform.

Many boilers will also have isolation Many boilers will also have isolation valves between the boiler and the valves between the boiler and the gauge glass shut off valves.gauge glass shut off valves.


Superheater VentSuperheater Vent

The Superheater Vent Valve is a The Superheater Vent Valve is a globe valve mounted on the globe valve mounted on the superheater outlet. It permits the superheater outlet. It permits the escape of air and steam when escape of air and steam when warming up and securing the boiler. warming up and securing the boiler.

Superheater VentSuperheater Vent

The prime purpose of the superheater The prime purpose of the superheater vent valve is to permit steam vent valve is to permit steam circulation:circulation:

Through the superheater during warm Through the superheater during warm up.up.

When securing the boilerWhen securing the boiler Or at any other time proper flow Or at any other time proper flow

through the superheater is doubtful.through the superheater is doubtful.

Superheater DrainSuperheater Drain

The Superheater Drain Valve is The Superheater Drain Valve is connected to the lowest point on the connected to the lowest point on the superheater and is generally a globe superheater and is generally a globe valve. valve.

It is used to drain the superheater It is used to drain the superheater during warm up procedures during warm up procedures

It may be used to permit drainage It may be used to permit drainage during boiler operation.during boiler operation.

Superheater Vent and DrainSuperheater Vent and Drain

Superheater Vent and DrainSuperheater Vent and DrainSuperheater Vent

Superheater Drain

Economizer Vent ValveEconomizer Vent Valve

The Economizer Vent Valve is a globe The Economizer Vent Valve is a globe valve and is mounted at the highest valve and is mounted at the highest part of the economizer. part of the economizer.

It is used to vent all air and/or steam It is used to vent all air and/or steam out, thus making sure the out, thus making sure the economizer is full of water. economizer is full of water.

It must also be opened if the It must also be opened if the economizer is to be drained to economizer is to be drained to prevent the formation of a vacuum.prevent the formation of a vacuum.

Economizer DrainEconomizer Drain

The Economizer Drain Valve is The Economizer Drain Valve is connected to the lowest of the connected to the lowest of the economizer.economizer.

It is used to drain the water out of It is used to drain the water out of the economizer for maintenance and the economizer for maintenance and inspection purposes.inspection purposes.

Economizer Vent and DrainEconomizer Vent and Drain


Economizer Vent

Economizer Drain

Boiler Mountings. Boiler mountings are nozzle connections, distance pieces, valves or fittings attached directly to the boiler and are always subjected.

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