Boiler Mountings – Types, Functions, Importance for Boiler Operation

What are Boiler Mountings? 

Created Boiler mountings diagram for educational purpose

 👉 INTRODUCTION 

Boiler is a mechanical equipments that used to generate steam by heating water under high pressure and temperature. 

The steam produced in a boiler is  used in industries such as power plants, sugar mills, textile industries, chemical plants, paper mill and for heating purposes. Since steam is generated at very high pressure, boiler operation involves significant safety risks.

Inside a boiler, steam pressure plays a very important role. If the pressure becomes too low, the boiler will not perform efficiently. If the pressure becomes too high, it can lead to serious accidents such as boiler explosion.  

     Therefore, controlling and monitoring steam pressure is essential for safe boiler operation.

👉 To ensure safety, certain essential devices are fitted on the boiler. These devices are known as Boiler Mountings. 

Boiler mountings are mandatory safety devices that help in controlling pressure, maintaining water level, regulating steam flow, and protecting the boiler during abnormal conditions.

Without boiler mountings, safe operation of a boiler is not possible, and operating a boiler without them is technically unsafe and legally prohibited. Hence, boiler mountings are considered the backbone of boiler safety.

👉 Role of Steam Pressure in a Boiler

Steam pressure determines the efficiency and safety of a boiler.

Low steam pressure results in poor performance of machines.

Excessive steam pressure increases the risk of boiler damage or explosion.

Therefore, steam pressure must be continuously monitored and controlled using suitable boiler mountings.

👉 Why Safety Devices are Necessary in a Boiler

A boiler operates continuously under high pressure and temperature. 

If Water level falls below the safe limit

Steam pressure rises beyond allowable limits.

Steam flow becomes uncontrolled

serious accidents may occur.

 Boiler mountings act as safety devices that prevent such dangerous situations and ensure smooth and safe boiler operation.

Boiler mountings are mandatory safety components installed on a boiler to control pressure, water level, and steam flow during operation.

 

✅What are Boiler Mountings?

Boiler mountings are essential safety devices that are direct fitted installed on a boiler shell or drum to ensure safe operation, control, and protection during working conditions.

These devices are mandatory as per boiler safety rules.

In simple words :  Boiler mountings protect the boiler from accidents and unsafe conditions.

* Purpose of Boiler Mountings 

To ensure safe operation of the boiler

To control pressure, water level, and steam flow

To prevent overheating and boiler explosion

To help operators monitor boiler conditions

* Main Boiler Mountings (With Function) 

1️⃣ Safety Valve  

👉To read full content : Spring loaded Safety Valve - complete Guide

The safety valve is the most important boiler mounting.

It automatically releases excess steam when pressure exceeds the safe limit, or setted boiler working pressure.

There are three types of Boiler Safety Valves. (1) Lever Safety Valve (2) Dead weight Safety Valve (3) Spring Loaded Safety Valve. 

Function:

• Prevents Boiler from overpressure

• Protects the boiler from explosion

👉Here explained Spring Loaded Safety Valve

Spring Loaded Safety valve is a vital boiler mounting designed to maintain safe pressure inside the boiler.

 It operates by opening automatically when the steam pressure rises above the set value, allowing excess steam to escape. 

The valve remains closed under normal conditions due to spring force and reseats once the pressure returns to normal.

👉 It acts as a primary safety device to prevent overpressure and ensure safe and reliable boiler operation.

Hand drawn spring loaded safety valve diagram with Labeled its parts, used in boiler mounting and pressure safety system

2️⃣ Water Level Indicator (Gauge Glass)

👉To read about water level Indicator full details : Water level Indicator - complete Guide

It shows the actual water level inside the boiler drum.

Function:

Helps maintain proper water level

Prevents tube overheating

Proper water level prevent boiler overalls from damage risks

3️⃣ Pressure Gauge 

Working Principal:

A pressure gauge is used to measure the steam pressure inside the boiler. It generally works on the principal of Bourdon tube . When steam pressure increases, the Bourdon tube tends to straighten due to internal pressure.

This movement is transmitted through a mechanical linkage to a  needle, which moves over a calibrated scale. The pointer indicates the actual steam pressure inside the boiler, allowing the operator to take correct action if required.

Indicates steam pressure inside the boiler.

Function:

Continuous pressure monitoring.

Ensures safe operation.

4️⃣ Steam Stop Valve 

Working Principal:

The steam stop valve is fitted on the Boiler drum for steam supply outlet. It is a manually operated valve. When the hand wheel is rotated, the valve spindle moves upward or downward.

When the valve is opened, steam flows from the boiler to the steam pipeline. When the valve is closed, the steam flow is completely stopped. it helps in isolating the boiler from the steam line during shutdown or maintenance.

Controls steam flow from boiler to pipeline.

Function:

Regulates steam supply.

Isolates boiler during shutdown.

5️⃣ Feed Check Valve 

Working Principal:

The feed check valve is installed at the point where feed water enters the boiler. It works on two basic principles:

Control of water flow

Prevention of backflow

When feed water is supplied by the pump, the pressure of water opens the valve and allows water to enter the boiler. If the boiler pressure becomes higher than feed water pressure or if the pump stops, the valve automatically closes and prevents water from flowing back.

Controls the entry of feed water into the boiler.

Function:

Prevents backflow,

Maintains water level.

6️⃣ Blow-off Cock  ( Blowdown Valve )

Working Principal:

The Blow off cock mounted at the lowest part of the boiler. When this valve is opened, dirty water, mud, scale, and dissolved impurities are discharged out of the boiler due to steam pressure and gravity.

This process helps in maintaining water purity, quality and TDS inside the boiler and prevents accumulation of sludge at the bottom.

Used to remove mud, scale, tds and impurities.

Function:

• Improves water quality

• Increases boiler life

• Uses for boiler shutdown cleaning

7️⃣ Fusible Plug 

Working Principal:

A Fusible Plug fitted at the crown of the furnace. It contains a low melting point metal known as fusible metal. When the water level inside the boiler falls below the safe level, the fusible plug gets exposed to high temperature.

• Due to excessive heat, the fusible metal melts and allows steam and water to enter the furnace, thereby extinguishing the fire. This protects the boiler from overheating and possible explosion.

• A safety device fitted at the furnace crown plate.

Function:

• Protects boiler during low-water condition.

• Melts when water level becomes dangerously low and extinguishes the fire when water excess low

* Boiler Mountings vs Accessories 

Boiler Mountings: Safety devices (Mandatory)

Boiler Accessories: Efficiency improvement devices (Not mandatory)

> Conclusion :

Boiler mountings are essential safety components that ensure safe, controlled, and efficient boiler operation.

🛡️Important Safety Desclaimer:

This content and diagram created for educational purposes only. Boiler operation must be carried out only by trained and certified professionals as per local boiler rules and  regulations. Always follow the manufacture's guideline. Ignoring safety rules can lead to extremely hazardous situations, severe personal harm, and significant financial loss. 

We do not claim ownership of any third-party trademarks, brand names, or industrial designs that may appear incidentally.

If you are the rightful owner of any content and believe it has been used unintentionally, please contact us for immediate review and removal.

All technical information is shared here to promote safety awareness and knowledge in boiler operation and  maintenance.

Author note :

Written by Birendraprasad gupta.

Certified Boiler Professional with 30+ years of Boiler practical experience in operation and maintenance.