Bolted Bonnet Gate Valve: The Ultimate FAQ Guide

In today’s guide, I will answer all questions you have been asking about bolted bonnet gate valve.

In fact, you will learn the specifications, parts, working principle, pressure rating, and applications, just to mention a few.

So keep reading to learn more.

What Is Bolted Bonnet Gate Valve?

Bolted bonnet gate valve is a type of gate valve which offers sealing in larger valves and applications of high pressure.

In bolted bonnet gate valve, its valve body and bonnet are bolted and flanged together.

Bolted bonnet gate valve

Bolted bonnet gate valve

What Is The Difference Between Bolted Bonnet Gate Valve Vs. Welded Bonnet Gate Valve?

 Bonnet for valves

Bonnet for valves

Some of the differences between bolted bonnet gate valve and Welded Bonnet gate valve include:

  • Welded bonnet gate valves tend to be smaller than bolted bonnet gate valves.
  • Welded bonnet needs to be cut off from the system of piping to be reset.

While this is not the case with bolted bonnet gate valves as they do not require removal from the piping system.

  • Bolted bonnet gate valves are mostly used in steam piping systems. Welded bonnet gate valves, on the other hand, are mostly used in toxic or lethal service.

Which Are The Different Types Of Bonnets Of Bolted Bonnet Gate Valve?

Some of the different types of bonnets include:

  • Screw-in bonnets: they are mostly available in small sizes and ensure that the seal does not leak.
  • Union bonnets: they are secured in place using a union nut that sits on the bonnet’s lower edge. These nuts screw it into the
  • Pressure seal bonnets: they are good for applications of high pressure as they use internal pressure to form a great seal. Pressure seal bonnets possess a cup that is facing downwards put into the valve body which is forced outward with an increase in pressure.
  • Bolted bonnets: they ensure sufficient sealing in high-pressure applications.

Bonnet for valves

Bonnet for valves

What Are The Features Of Your Bolted Bonnet Gate Valve?

Some of the features of bolted bonnet gate valve include:

  • They are suitable for high-pressure applications.
  • Size ranges of NPS 2 inch to 60 inch
  • Temperature rate of 600 degrees Celsius.
  • Seats are either metallic or satellite.
  • Gaskets are spiral wounds, RTJ, and INOXGRAF.
  • Pressure rating in ASME classes 150-1500
  • Standard connections include socket weld and Buttweld.
  • Contains a bolted bonnet joint that has stronger leakproof that makes sure it is tight with higher torque of bolting.
  • Non-rotating stem.
  • End connections include BW, RF, FF, NPT, RTJ, SW, and CLAMPS.
  • Hard-faced seating faces can resist erosion.
  • Designed to ASME B16.34
  • The body of bolted bonnet gate valve is made from forgings of superior strength and optional cast steel.
  • Optional live loading of packing and leak off.
  • Its stem is designed according to API 602 requirements.

Are Bolted Bonnet Gate Valves Full Port Or Reduced Port Valves?

Bolted bonnet gate valves can either be full port or reduced port valves.

Full port valves give little resistance to flow and make it easy for the handwheel or actuator to turn fully when opening and closing.

However, in reduced port valves, it may be challenging to regulate the flow or pressure well. This is because the construction of the gate valve needs a lot of turns of the actuator or handwheel to open or close fully.

What Are The Main Parts Of Bolted Bonnet Gate Valve?

Parts of bolted bonnet gate valve

Part of bolted bonnet gate valve

Some of the main parts of bolted gate valve include:

  • Body: it ensures that the bolted bonnet gate valve possesses resistance to flow and optimum performance and strength.
  • Yoke and bonnet: the assemblies of the bonnet are built using the same standards as the body on the bonnet. Gate valves of a larger size make use of multi-piece designs of the bonnet.
  • Gland: it compresses the packing to form a stem seal above the backseat between the stem and bonnet.
  • Stem: it has an integral back seat shoulder that links to the integral backseat of the bonnet.
  • Wedge: it ensures that the bolted bonnet gate valve can shut off and cycle with ease.
  • Handwheel: it cycles the nuts of the bonnet gate valve.
  • Bonnet: it offers protection to the internal parts of a bolted bonnet gate valve. It can either be bolted or screwed to the valve body.

How Does A Bolted Bonnet Gate Valve Work?

A bolted bonnet gate valve works by blocking the path of flow of fluid through the insertion of a rectangular wedge or gate.

They are operated by the use of a threaded stem that links the actuator or handwheel to the gate’s stem.

When the bolted bonnet bate valve is fully open, it does not have to obstruct the path of fluid flow, thus a low-pressure drop. Bolted bonnet gate valve can be used in either a fully closed position or a fully open position.

The seat and gate of bolted bonnet gate valve carry out the task of shutting off the flow of fluid.

How Do You Operate Bolted Bonnet Gate Valve?

You can operate bolted bonnet gate valve using the following:

Handwheels

It operates the bolted bonnet gate valve manually when opening and closing it with the means to override the control system.

It is essential to indicate the neutral position on the gate valve to ensure that it works properly.

Handwheels can be mounted either on a separate screwed stem, on a spindle, or a screwed stem.

Valve Actuator

It is responsible for controlling and moving the bolted bonnet gate valve by opening and closing it.

It needs a control signal and a source of energy for it to be operating effectively.

The control signal’s source of energy can be either pneumatic, electric or hydraulic, or even human power.

It responds by converting the energy into mechanical motion in the bolted bonnet gate valve.

What Are The Applications Of Bolted Bonnet Gate Valve?

Some of the applications of bolted bonnet gate valve:

  • Transmission pipelines
  • Offshore platforms
  • Measuring stations
  • Onshore terminals
  • Compression, pumping, and reinjection units.
  • Surge-relief skids

Which Are The Essential Accessories For Bolted Bonnet Gate Valve?

Some of the essential accessories for bolted bonnet gate valve include:

  • Grease fitting: it ensures that the stem is easily lubricated.
  • Backseat bushing: it enables the stuffing box to have a perfect shutoff and separate the packing from flow exposure.
  • Gland flange: it applies pressure onto the gland to ensure accuracy in packing adjustments.
  • Gland bolts and nuts: they allow for easy adjustment of the packing compression.
  • Packing: it forms a seal above the backseat between the stem and bonnet.
  • Stuffing box: it is used to hold the packing.
  • Stem nut: it ensures proper alignment of the stem by giving precision.
  • Yoke bushing: it ensures the stem nut is secured to the bonnet assembly.
  • Handwheel Nut: it ensures that the hand when is well secured to the bonnet assembly.
  • Set screw: it ensures that the handwheel does not get loose.
  • Bonnet gasket: it forms a seal that is free from leaks between the body and the bonnet.
  • Bonnet studs and nuts: they ensure that the bonnet is secured to the body.
  • Seat rings: they are aligned to the seal and welded into the valve to make sure a shutoff is stable.
  • Spacer ring: they help the packing rings in forming a seal above the backseat and between the stem and bonnet.

Do You Require A Gasket For Sealing The Connection Between Bonnet And Body Of Bolted Bonnet Gate Valve?

Yes, you require a gasket for sealing the connection between the bonnet and the body of bolted bonnet gate valve.

Sheet gasket materials are used to seal the connection of the bolted bonnet gate valve at low pressure while metallic gaskets are used at high pressure.

Bolted bonnet gate valve

Bolted bonnet gate valve

Where Should You Use Bolted Bonnet Gate Valve?

You should use bolted bonnet gate valve in the following areas:

  • Natural gas processing
  • Offshore and subsea areas
  • Petroleum refining plants
  • Petrochemical plants
  • Power plants
  • Pipelines
  • Mining plants
  • Chemical plants

What Is Cryogenic Bolted Bonnet Gate Valve?

The cryogenic bolted bonnet gate valve has bonnets that are extended with enough column length.

They are supplied to ensure that the stem packing is at a sufficient interval from the cold fluid to remain operational.

Their size ranges between ¼ inch and 2 inches and their standard connections are either flanged or socket weld.

How Do You Tell That A Bolted Bonnet Gate Valve Is Open Or Closed?

You will tell that bolted bonnet gate valve is open when the stem is protruding beyond the handle.

You will tell that it is closed if the stem is not protruding from the handle as the clockwise rotation of the valve moves the stem back to the valve.

Bolted bonnet gate valve is opened by turning the handle in an anticlockwise direction and closed when rotated in the clockwise direction.

What Is The Working Temperature Of Bolted Bonnet Gate Valve?

The working temperature of bolted bonnet gate valve design according to ASME B16.34 standards is between -29 to 200 degrees Celsius.

How Does Bolted Bonnet Gate Valve Vs. Pressure Seal Gate Valve Compare?

Bolted bonnet gate valve compares to pressure seal gate valve in the following ways:

Bolted bonnet gate valve is joined using nuts and studs with a gasket of suitable material or design inserted in between flanges for sealing.

The nuts, studs, or bolts are tightened to meet the pattern which was stated by the manufacturer to ensure optimal sealing of the bolted bonnet gate valve.

However, in bolted bonnet gate valve, an increase in pressure also raises the chances of potentially leaking into the system.

The pressure seal gate valve is made to include bonnet take-up bolts that raise the bonnet and seal against the pressure seal gasket.

In this way, a seal is formed between the inner I.D of the valve body and the gasket.

A load of the pressure-resistant gate valve is maintained by a ring.

When pressure builds in the system, the same will apply to the load that is on the bonnet and the pressure seal gasket.

In pressure seal gate valves, as pressure on creases in the system, there will be a reduction of potential leaks through the body or bonnet.

Pressure seal gate valve has benefits over bolted bonnet gate valve in applications like main steam, turbine bypass.

It is also suited for turbine bypass and other plant systems which need valves that can tackle challenges of temperature and high pressure.

However, because pressure seal gate valve relies so much on system pressure in sealing, they have limitations.

They can only be used well where the minimum operating pressure consistency is more than 500psi.

What Is The Recommended Bolting Torque For Bolted Bonnet Gate Valve?

The recommended bolting torque for bolted bonnet gate valve is as illustrated in the table below:

Valve sizeB7/B16/L7

Torque (Nm)

B7M/ L7M

Torque (Nm)

B8 CL.2/ B8M CL.2

Torque (Nm)

 

3/8’’-16 UNC-2B272027
7/16″-14 UNC-2B

 

403535
1/2″-13 UNC-2B

 

756060
9/16″-12 UNC-2B

 

907590
5/8″-11 UNC-2B

 

135110115
3/4″-10 UNC-2B

 

260200200
7/8″-9 UNC-2B

 

390285270
1 1/8″-8 UN-2B

 

775675600
1″-8 UNC-2B

 

530475475
1 1/4″-8UN-2B

 

1100950900
1 3/8″-8 UN-2B150013001020
1 1/2″-8 UN-2B

 

190017001290
1 5/8″-8 UN-2B

 

245021501630
1 3/4″-8 UN-2B

 

312027502040
1 7/8″-8 UN-2B

 

380033102510
2″-8 UN-2B

 

461041103060
2 1/4″-8 UN-2B665058504410
2 1/2″-8 UN-2B

 

895079705970
2 3/4″-8 UN-2B

 

11950106207870
3″-8 UN-2B156001373010310

How Do You Disassemble And Reassemble Bolted Bonnet Gate Valve?

The disassembling bolted bonnet gate valve entails the following steps:

  • First, the handwheel nut should be unscrewed.
  • Raise the handwheel upwards out of the yoke sleeve.
  • Remove screws from the retainer nut and the yoke sleeve.
  • Raise the yoke sleeve upwards out of the bonnet.
  • Unthread the gland fasteners.
  • Eliminate screws from the fasteners of the body bonnet.
  • Lift the bonnet above the stem together with the gland flange and the gland.
  • After this, remove the gland flange, the gland, and packings.
  • Unscrew the bonnet bush and take it in a downward direction from the bonnet.
  • Finally, lift the stem the disk, and the body of the bolted bonnet gate valve.

Reassembling of a bolted bonnet gate valve is a vice versa of the above series of steps whereby you will begin with the latter to the former.

What Is The deal Pressure Rating Of Bolted Bonnet Gate Valve?

The ideal pressure rating of bolted bonnet gate vale is from 150 to 600 psi.

The low-pressure range of bolted bonnet gate valve is designed according to standards by API 600 and ASME B16.34.

Which Are The Testing And Inspection Standards For Bolted Bonnet Gate Valve?

The testing and inspection standards for bolted bonnet gate valve include:

  • API 598
  • API 6D
  • MESC SPE 77/101
  • MESC SPE 77/102
  • ISO 5208
  • API6FA
  • ISO 10497
  • ISO 15848-1 &2
  • Bs6364

What Is The Size Range Of Your Bolted Bonnet Gate Valve?

The size range of bolted bonnet gate valve design is between 2 inches and 88 inches. However, it is important to note that manufacturers can custom make for you larger sizes of bolted bonnet gate valves meeting your specifications.

How Do You Maintain Bolted Bonnet Gate Valve Under Pressure?

You should ensure that bolted bonnet gate valve is used within the specified pressure conditions as per ASME B16.34 Section 2.

It is also essential to make sure that you operate the bolted bonnet gate valve within the specified pressure limit.

In case you require additional support always consult with the manufacture.

You should also always operate the bolted bonnet gate valve up to a fully open position to eliminate any pressure that may be trapped within the cavity.

What Is Bolted Bonnet Gate Valve Price?

Bolted bonnet gate valve

Bolted bonnet gate valve

The price of bolted bonnet gate valve tends to vary depending on factors such as:

  • Materials used in its construction.
  • Size
  • Types of end connections
  • Operation features
  • Pressure and temperature rating

Which Are The Available Body Material For Bolted Bonnet Gate Valves?

The material that you can use to construct the body for a bolted bonnet gate valve include the following:

  • Various grades of carbon
  • Low alloy steel
  • Stainless steel
  • Cast steel
  • Nickel alloy
  • Forged steel
  • Brass
  • Bronze
  • Cast iron
  • Ductile iron

Which Connection Types Can You Use In Bonnet Gate Valve?

The different connection types include:

Threaded Connections

This connection will link the pipe and the bonnet gate valve using threads.

Also, it is a common type of connection and is suitable for small bonnet gate valves in low-pressure systems.

Besides, it requires no extra components such as nuts and bolts hence, is affordable and easy to install.

Two types of threading exist:

  1. Internal and external threads
  2. Parallel and tapered threads

Many bonnet gate valves apply tapered thread connection types.

Besides, these threads are hard to repair when there are leakages and may need a full replacement.

Welded Connections

This connection involves welding the bonnet gate valve directly to the piping system.

By welding, you create a tight and leak-proof joint.

Besides, they are costlier than flanged connections but will guarantee you proper linkage between the valve, pipe, and fittings.

Welded connections are suitable in areas that need complete leak-proof systems such as:

  1. High-pressure pipeline systems
  2. High-temperature pipeline systems

There are two types of welded connections:

Socket Weld

The end of the welded bonnet gate valve has the shape of a socket where you insert the pipe for welding.

This connection applies fillet welds to join two parts and they are suitable for valves of 2 inches or less.

Butt Weld

The ends of these valves and piping systems are butted to one another.

Thereafter, you will weld these parts to create a joint.

Butt welds are suitable on steel valves, however, you can use them on any valve irrespective of their size.

Flanged Connections

This type of connection is suitable for connecting bonnet gate valves to pipelines.

Also, you can use it in any pressure level or valve size situation.

Flanged connections contain two flanges that you will attach using nuts and stud bolts.

Besides, they are easy to install and uninstall when you need to repair or replace them.

How Does Bolted Bonnet Gate Valve Compare To OS & Y Gate Valve?

Here is how these two compare:

Bolted Bonnet Gate Valve

These valves are suitable for large applications in the chemical, petrochemical, gas, and oil industries.

This valve is good for applications that need tight shutoffs.

Also, it needs gaskets to seal the joint between the bonnet and the body.

When using low-pressure valves, you will use sheet gaskets and at high pressure, metallic gaskets are suitable.

This valve has a rotating stem that does not rise and the threads are within the chamber.

OS & Y Gate Valve [Outside Screw And Yoke]

This type of gate valve is common in controlling the flow of water to fire sprinkler units.

When you turn the handle, the gate will rise or lower since it interacts directly with the stem.

Also, you will see the stem rise outside the gate valve as the handle remains in a fixed position.

Besides, it is easy to see if the valve is closed or opened as it is vital for maintaining fire protection.

What Is A union Bonnet Valve?

This is a valve that is held by a union nut that sits on the bottom part of the bonnet and will screw to the threads of the valve.

The design of a union bonnet valve ensures a leak-proof seal and the nut will not deteriorate when you frequently remove the bonnet.

Union bonnet valves are suitable for applications that need frequent maintenance and inspection.

How Does Bonnet Globe Valve Compare to Bolted Bonnet Gate Valve?

These valves contain similar external housing but will operate differently.

Bonnet globe valves offer good throttling capabilities while bolted bonnet gate valves are suitable for isolation.

Also, bolted bonnet gate valves offer a tight seal hence you can use it upstream of a bonnet globe valve.

Bonnet globe valves need more torque to operate than bolted bonnet gate valves.

Besides, bonnet gate valves will produce noise, vibrations, and disk damage when you try to regulate flow with it.

Bonnet gate valves can conduct flows in both directions while bolted bonnet gate valves have flow directions on them.

How Does Bolted Bonnet Vs Welded Bonnet In Valves Compare?

Here is how these two compare:

  • Bolted bonnet valvesHere, you will use studs and nuts to join the body and the bonnet of the valve.

    Besides, depending on the application, you will use a gasket between the body and the bonnet.

    To provide a seal, you will tighten the nuts and bolts per the manufacturer’s description.

    However, when the pressure increases, there is a risk of potential leakage between the body and the bonnet joint.

  • Welded bonnet valvesThis is a type of valve where you weld the body and the bonnet together.

    The weld in this valve makes it leak-proof and is suitable for high pressure and temperature applications.

How Does Bolted Bonnet Check Valve Compare to Bolted Bonnet Gate Valve?

Bolted bonnet check valves operate by preventing the backflow of fluid in the piping unit.

The flow of materials in the pipeline will activate check valves since the pressure will open the valve.

Also, any reversal flow in the fluid will close the check valve.

A bolted bonnet gate valve allows fluid to flow or not when you open or close the gate and fluid can flow in all directions.

What Is The Difference Between Bolted Bonnet Ball Valve And Bolted Bonnet Gate Valve?

A bolted bonnet gate valve operates by raising or lowering the gate to begin or stop fluid flow.

Bolted bonnet ball valve operates by rotating a ball-shaped disk to start or stop the flow of fluid.

At Kinvalve, we will help you find a suitable bolted bonnet gate valve for your unique applications – contact us now.

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