Valve Desk

04/01/2022

06/01/2021

Steam Desuperheater Working and Types:- The equipment which is used to bring down the temperature of a superheated steam is called a steam desuperheater...

03/04/2020

Deluge Valve Operation:-
A Deluge system (automatic High Velocity Water Spray System) is a fixed fire protection system, which totally floods an area with pressurized water through a system of piping with open nozzles & sprinklers.

03/04/2020

Reference-https://www.e-pneumatic.com
How Do Flow Control Valves Work?

https://www.e-pneumatic.com/blog/flow-control-valves/

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03/04/2020

Please refer the below link regarding different control valve controllers.

https://blog.kimray.com/what-is-a-control-valve-controller/

Every oil and gas control valve needs a control valve controller. Also known as pilots, controllers tell valves when to open and close.

03/04/2020

https://www.arcweb.com/blog/what-control-valves

A control valve regulates the rate of fluid flow as the position of the valve plug or disk is changed by an actuator. Control valves are used to maintain a process variable as close as possible to the desired set point.

02/04/2020

Selecting the Right Valve for your application:-

Suitability of the valve type can be defined. There is no single valve type which suits all applications Each type of valve plays a specific role. So it’s important to know which one to choose for the task at hand. Let’s take a look at few Valves that are widely used for control applications

Globe Valves:-

Ideal choice for Good control in case of high differential pressure applications. These Valves are ideal for noise reduction with clean flow media and can also be used for micro flow service.

Maintaining or retrofitting of Globe Valve is easy, which is especially helpful if process conditions change quickly or plant capacity increases marginally.

Butterfly Valve:-

Butterfly Valves are lightweight, economical solutions and are especially attractive valve solutions in large sizes. Butterfly Valves offer near linear flow and are ideal for instances which require limited pressure drop.

Plug Valves:-

These Valves are a compact and reliable solution for general and even more demanding applications. These valves are widely used in refineries and petrochemical plants, as they can also handle Slurries and viscous fluid. Plug Valves are best suited for applications which require zero residue inside the valve.

02/04/2020

Flow co-efficient:-

The most important valve parameter for calculating the size of a control valve is the flow coefficient, Cv. Calculation of Cv depends upon degree of compressibility of fluid

02/04/2020

Selecting a Control Valve -

A control valve is a power operated device capable of modulating flow at varying degrees between minimal flow and full capacity in response to a signal from the controlling system. Control valves play a major role in the everyday effort to increase process plant profitability and conserve energy.

Understanding the Controlling of the Valve
Control valve basically follows the instruction received from controlling loop (sensing element and the controller) Sensing element sends a signal to controller which is intern conveyed to the positioner mounted on the Valve. The Postioner controls the position of the valve through actuator.

Parameters for selection-

To select a right fit option following parameter of the media are very important. Such as state (vapour, liquid or two-phase), vapour pressure, flow-prate, inlet and outlet pressures, inlet temperature, density, molecular weight, viscosity, specific heat ratio, critical temperature and critical pressure.

Also, while defining the flow-rate, one should include certain safety margin. One must also consider ambient conditions at site, system geometry, pipeline sizing, MOC, fail-safe position etc.

02/04/2020

01/04/2020

18/01/2020

PID stands for Proportional Integral Derivative. PID controller is used to control final control element with proper controller tuning.

18/01/2020

How to choose a control valve depends on the basic requirements and selection depend on their ability to perform specific functions.

17/01/2020

Metso: “By using 3D printing, we were able to develop and manufacture complex, cutting-edge components faster, with improved reliability, safety, and valve availability.” Innovation is in the DNA of Metso experts. At Valve World Americas, the industrial flow control expo & conference, David Bayreuther will share his thoughts during the Actuated Valve Assembly Workshop, J.P. Garcia will chair Valve Design Workshop where Jukka Borgman will speak about the 3D printing of valve parts. Join us! Metso

17/01/2020

Valve Condition Monitoring involves the seamless collection and interpretation of valve condition data by valve diagnostics experts

17/11/2019

What will control unit mean??

- The pressure to be regulated is transferred to the pressure control valve mechanism via the control unit.

The pressure functioning on the control surface closes (pressure reducing valve) or opens (backpressure regulator) the valve against the spring force.

Three construction varieties are distinguished:
1. diaphragm
2. piston with O-ring and different seals
3. bellow

17/11/2019

How will cavitation damage be contained?

-Several ways exist for treating cavitation in control valves. The primary is to pick out valves with high values of fl (recovery factor) eliminating cavitation.

The second is to make sure that the plug and seat area unit product of a material which will resist the damage (e.g. stellite hard facing).

The third is to control wherever the bubbles collapse and keep this aloof from vulnerable elements (for instance on the brink of internal surface of valve body or pipe).

16/11/2019

What is the distinction between “Rangeability” and “Turn-down” in an exceedingly steam DE-superheating system ??

The term “rangeability” commonly refers to a mechanical conception applied to one throttling device. F.i. for a control valve the “rangeability” is magnitude relation between the max flow (or Cv) and also the minimum governable flow (or Cv).

When 2 of such devices area unit associated, in our case on water and steam line, the minimum and most governable flow of the system as an entire can be tormented by different factors.

Typically in steam acquisition systems some prescriptions in terms of steam velocity area unit needed for a decent performance (not under..) and thus the operating range of the system is also under the “rangeability” of every individual device.

Therefore the magnitude relation between max. and minimum governable flow of the complete system is what we tend to decision “turn down”.

16/11/2019

Why a control valve on refrigerant Service can not be mounted with actuator in horizontal position?

The working rule of the extended bonnet (named “cold box”) employed in refrigerant service (below -100°C) is predicated on the principle that portion of LNG that evaporates and stagnates within the higher portion of the bonnet contains a operate of thermal insulation between the process fluid and also the gland packing.

In this manner ice formation on valve stem is avoided. To grant this profit the stem/actuator axis should be in upright position. so valves put in on a vertical pipe (with the actuator in horizontal position) cannot work properly.

15/11/2019

Reasons that Valves Leak:

Common causes of leakage of valve include: –

- Valve is not completely closed. This may be due to multiple factors, including

- Valve seat preventing complete closure owing to rust, line debris, etc.

- Insufficient actuator travel

- Valve seat damage, e.g. scored

- Valve seals damage

15/11/2019

How to define seat leak class for control valves?

-A control valve’s ability to shut off must do with several factors. Seat material, actuator thrust, pressure drop, and also the kind plug (balanced or unbalanced) will all play a section in however well a specific control valve shuts off. Seat leak Classifications There is literally six completely different seat leak classifications as outlined by IEC 60534-4 std or ANSI/FCI seventy.2.

They normally range from class IV to class Vl class IV is additionally referred to as metal to metal. it’s the type of leak rate you’ll expect from a valve with a metal plug and metal seat. Class Vl is understood as a soft seat classification.

Soft Seat Valves area unit those wherever either the plug or seat or each area unit made of some reasonably composition material like Teflon or similar.

15/11/2019

What is the difference between flashing and cavitation?

- Cavitation may be a condition that happens in liquid flow wherever the inner pressure of the liquid, at some Location falls below the vapour pressure and vapour bubbles formation takes place.

After this time the pressure rises higher than the vapour pressure once more and through this pressure recover stage (recall additionally the conception of FL) the bubbles collapse, and cavitation takes place.

Flashing may be a condition that happens with liquid flow wherever the pressure falls below the vapour pressure (same as cavitation) and remains below it. There are a unit then 2 phases flowing (i.e. liquid and vapour) downstream and no collapsing of bubbles takes place.

15/11/2019

What is the valve seat?

The valve seat is that the apron for an outlined flow through opening within the valve through that the medium to be regulated needs to flow.

15/11/2019

What is the valve cone?

-The valve cone may be a movable component inside the valve that bears on the valve seat. By means that of the cone stroke the valve is opened, throttled or closed.

14/11/2019

Classification of control valve leakage

Control valves are intended to throttle flows and without valve leakage they are not required to near 100 percent.

The capacity to shut down has to do with valve type. There are very bad shutdown skills for double seated control valves. Moreover-the guide, the seat material, the thrust of the actuator, the pressure drop and the type of fluid all play a role in how well specific control valves shut off.
There are two kinds of valve leakage: fugitive emissions from the valve to the atmosphere, and leakage through the valve but within the piping scheme. Fugitive emissions can be harmful to the environment as well as a potential risk to safety.

Valve Leakage Classifications

Class I – Valve Leakage Classifications
In construction and design, identical to Class II, III and IV, but no real shop test is performed. Also known as dust tight, Cass I can refer to sitting metal or resilient valves.

Class II – Valve Leakage Classifications
Designed for double port or balanced single port valves with metal piston ring seal and metal to metal seats.

0.5% leakage of full open valve capacity
Service dP or 50 psid (3.4 bar differential), whichever is lower at 50 to 125 oF
Test medium air at 45 to 60 psig is the test fluid

Class III – Valve Leakage Classifications
Intended for the same types of valves as in Class II.

0.1% leakage of full open valve capacity
Service dP or 50 psid (3.4 bar differential), whichever is lower at 50 to 125 oF
Test medium air at 45 to 60 psig is the test fluid
Typical designs:

balanced, double port, smooth seats, low seat load
Balanced, single port, single graphite piston ring, metal lapped seats, medium seat load

Class IV – Valve Leakage Classifications
Designed for single port and balanced single port valves with additional tight seals for pistons and metal to-metal seats.

0.01% Full open valve capability leakage
Service dP or 50 psid (3.4 bar difference), reduced at 50 to 125 oF
Test medium air at 45 to 60 psig.

Class V – Valve Leakage Classifications
Intended for the same types of valves as Class IV

The test fluid is water at 100 psig or operating pressure
Leakage allowed is limited to 5 x 10-4 ml per minute per inch of or***ce diameter per psi differential
Service dP at 50 to 125 oF

Class Vl – Valve Leakage Classifications
Class Vl is known as a classification for smooth seats. Soft Seat Valves are those where the seat or shut-off disk or both are made of some resilient material like polytetrafluoroethylene (PTFE). Designed for resilient valves for seating.

The test fluid is air or nitrogen
Pressure lower than 50 psig or working pressure
The leakage limit depends on the volume of the valve and varies between 0.15 and 6.75 ml per minute for valve sizes 1 to 8 inches