How to choose the right process control valves

Modern process control valves offer a wide range of features and benefits for industries that require precise control over fluids, steam and other gases. With so many control valves on the market, it is important to establish the features that will deliver the most cost-effective design for a particular application. Damien Moran, Field Segment Manager, Hygienic - Pharmaceutical at Bürkert, looks at some of the basic differentiators as well as some recent design developments.

Control valves are used to manage the flow rate of a liquid or a gas and in turn control the temperature, pressure or liquid level within a process. As such, control valves are defined by the way in which they operate to control flow and include globe valves, angle seat, diaphragm, quarter-turn, knife and needle valves, to name a few. In most cases the valve bodies are made from metal; either brass, forged steel or, in hygienic applications, 316 stainless steel.

Actuators use an on-board system that measures the position of the valve with varying degrees of accuracy, depending on the application. A contactless, digital encoder can place the valve in any of a thousand positions, making it very accurate, while more rudimentary measurements can be applied to less sensitive designs.

One of the main areas of debate when specifying control valves is determining the size of the valve required.

Often process engineers will know the pipe diameter that is used in an application, and it is tempting to take that as the defining characteristic for the control valve. Of greater importance are the flow conditions within the system, as these will dictate the size of the orifice within the control valve. The pressure either side of the valve and the expected flow rate are essential pieces of information when deciding on the valve design.

Improving efficiency

Inside the valve body, the actuator design is predominantly either a piston or a diaphragm design. The piston design typically offers a smaller, more compact valve, which is also lighter and easier to handle than the diaphragm designs. Actuators are usually made from stainless steel or polyphenolsulpide (PPS), which is a chemically resistant plastic. The actuator is topped off by the control head or positioner.

Older, pneumatically operated positioners had a flapper/nozzle arrangement and operated on 3-15psi, so no matter what the state of the valve, open closed or somewhere in between, the system was always expelling some compressed air to the atmosphere.

Compressed air is an expensive commodity, requiring considerable energy to generate and when a manufacturing line is equipped with multiple process control valves all venting to the atmosphere, this can equate to a considerable waste of energy. It is important then to establish not only the most appropriate valve design, but also a cost-effective solution that takes account of annual running costs.

Modern, digital, electro-pneumatic valves that use micro solenoid valves to control the air in and out of the actuator have introduced significant improvements for operators. This design means that while the valve is fully open, fully closed or in a steady state, it is not consuming any air. This and many other engineering improvements have made substantial advances in both economy and precision.

Flexible designs

Valve seats can be interchangeable within a standard valve body, which allows the valve to fit existing pipework and the valve seat to the sized to the application more accurately. In some cases, this can be achieved after the valve has been installed, which would enable a process change to be accommodated without replacing the complete valve assembly.

Selecting the most appropriate seal materials is also an important step to ensure reliable operation; steam processes would normally use metal-to-metal seals, whereas a process that included a sterilisation stage may require chemically resistant seals.

Having installed a new valve, setting it up is now comparatively easy and much less time-consuming. In-built calibration procedures, such as Bürkert's X-tune, perform the initial setup procedures automatically, measuring the air required to open and close the valve, the resistance of the piston seals on the valve stem and the response time of the valve itself. Once complete, the valve is ready for normal operation.

Improving safety

Control valves should be specified so that they operate in the 40-85 per cent range so if the valve is commanded to a 10 per cent setting, it can detect that something has potentially gone wrong with the control system and the best course of action is to close the valve completely. If the valve is commanded to a position of 10 per cent or less this can cause very high fluid or gas velocities, which have damaging effects on the system and cause considerable noise and damage to the valve itself.

Modern control functionality can offer a solution that acts as a safety device to prevent damage to the process pipework and components. By building in a fail-safe mechanism, any valve position setting below a pre-set threshold will result in the valve closing completely, preventing damage to the surrounding system.

Control inputs can also include safety circuits to ensure safe operating conditions within the process equipment. For example, if an access panel on a vessel containing steam is opened, an interlock switch will open and the valve controlling the steam supply to the vessel can be closed automatically, helping to mitigate any risks.

Improving reliability

Many process control environments offer less than ideal conditions for long-term reliability. Moisture-laden atmospheres, corrosive chemicals and regular wash-downs all have the capacity to shorten the service life of a process control valve. One of the potential weaknesses of the actuator is the spring chamber where atmospheric air is drawn in each time the valve operates.

One option is to use clean, instrument air to replenish the spring chamber, preventing any contamination from entering. This offers a defence against the ingress of airborne contaminants by diverting a small amount of clean control air into the control head, maintaining a slight positive pressure, thus achieving a simple, innovative solution. This prevents corrosion of the internal elements and can make a significant improvement to reliability and longevity in certain operating conditions.

Ultimately, choosing the most appropriate process control valve can be a complex task that is often best achieved with the assistance of expert knowledge. Working directly with manufacturers or knowledgeable distributors enables process control systems to be optimised for long-term reliability as well as precision and efficiency.

Learn more about process control valves at www.burkert.co.uk.

Burkert Fluid Control Systems

Fluid Control Centre
1 Bridge End
Cirencester
GL7 1QY
UNITED KINGDOM

+44 (0)1285 648720

sales.uk@burkert.com

www.burkert.co.uk

More from Burkert Fluid Control Systems

New video just released by Burkert

Posted 4 hours ago

In pursuit of hygiene, accuracy and cost-effectiveness

Posted 5 days ago

Fast action steps up effectiveness of patient care

Posted 2 weeks ago

The right brew for steam temperature control

Posted 3 weeks ago

Long life to continuous control valves

Posted 1 month ago

Unifying the process control network

Posted 1 month ago

Bürkert valves ensure latest standards prevail

Posted 2 months ago

Sweet success for process control reliability

Posted 2 months ago

Full steam ahead for training

Posted 3 months ago

Process valve island increases dosing accuracy

Posted 4 months ago

Carbon capture technology on the rise

Posted 4 months ago

Water treatment improvements for power station hit full flow

Posted 5 months ago

Network integration – search for value and simplicity

Posted 5 months ago

ATEX certification for new pneumatic valve island

Posted 6 months ago

Ironing out the doubt: iron measurement in water quality analysis

Posted 6 months ago

Flowmeter range expands

Posted 7 months ago

Pure water: quality monitoring is a vital asset

Posted 8 months ago

New flow controller for low volumes

Posted 8 months ago

Delivering high precision for time-pressure microlitre dosing

Posted 9 months ago

Monitoring reverse osmosis systems

Posted 1 year ago

Online water analysis module continuously measures iron content

Posted 1 year ago

Movie of the month

Posted 1 year ago

Time-pressure controller for high-precision microlitre dosing

Posted 1 year ago

How to simplify industrial process automation using IO-Link

Posted 1 year ago

Multi-parameter flow meter cuts waste by identifying fluids

Posted 1 year ago

Burkert invests in fully automated multi-medium testing facility

Posted 1 year ago

Burkert UK now supplying customisable micro precision pumps

Posted 1 year ago

Bürkert appoints new Account Manager for the South West

Posted 1 year ago

Smart valve positioner features IO-Link connectivity

Posted 1 year ago

Bürkert delivers savings for new life science facility

Posted 1 year ago

Controller achieves micro-precision for time-pressure dosing

Posted 1 year ago

Intelligent valve islands for process automation applications

Posted 1 year ago

Retrofitted control heads extend life of 200 process valves

Posted 1 year ago

Enhanced radar level measurement for hygienic applications

Posted 1 year ago

Bürkert microfluidics expertise improves antibody discovery

Posted 1 year ago

Bürkert launches compact Type 6164 cartridge valve

Posted 1 year ago

Continuous monitoring and analysis of water quality

Posted 1 year ago

What is needed to improve fuel cell technology?

Posted 1 year ago

Flow measurement in the food and beverage sector

Posted 1 year ago

Bürkert virtual exhibition stand offers web and VR experience

Posted 2 years ago

Integrated water quality monitoring for water treatment service

Posted 2 years ago

Movie of the month

Posted 2 years ago

Flexible water analysis system saves time and money

Posted 2 years ago

Bürkert UK expands stock of standard process valves

Posted 2 years ago

Hygienic flowmeter specified for pharmaceutical cleaning system

Posted 2 years ago

Process control expertise at the ISPE Europe Annual Conference

Posted 2 years ago

Flowmeter gains the ability to detect different fluids

Posted 2 years ago

Finding the right partner for hygienic process control projects

Posted 2 years ago

Burkert UK expands product range and increases stockholding

Posted 2 years ago

Brewery upgrade improves reliability

Posted 2 years ago

multiCELL controller supports Champagne production

Posted 2 years ago

Support for system integrators

Posted 2 years ago

Burkert contributes to more efficient fluid control system

Posted 2 years ago

Burkert to exhibit hygienic products at EHEDG Conference 2018

Posted 2 years ago

Patties still a firm favourite thanks to 10-year-lasting valves

Posted 2 years ago

Multifunction controller features Ethernet connectivity

Posted 2 years ago

Solenoid control in potentially explosive atmospheres

Posted 2 years ago

New monitoring system simplifies micro-filtration of water

Posted 3 years ago

Micro-dosing technology and process integration

Posted 3 years ago

Using automation to improve process water quality

Posted 3 years ago

Movie of the month

Posted 3 years ago

Optimising repeatability and efficiency through automation

Posted 3 years ago

New flowmeters to look out for in 2018

Posted 3 years ago

Simplified process control for reverse osmosis plant

Posted 3 years ago

Comparing flowmeters: Coriolis vs. Surface Acoustic Wave

Posted 3 years ago

Precision control for CIP processes

Posted 3 years ago

Pneumatic valve island improves flexibility and diagnostics

Posted 3 years ago

Bürkert's new valve control heads provide networking options

Posted 3 years ago

Using Industry 4.0 to optimise process control

Posted 3 years ago

Re-engineering diaphragm valves

Posted 3 years ago

Taking pneumatic process control to a new level

Posted 3 years ago

Precise flow control for efficient, accurate pneumatic conveying

Posted 3 years ago

High-temperature control for exhaust analysis

Posted 3 years ago

Burkert: managing a culture of innovation

Posted 3 years ago

More function modules for Burkert compact water analysis system

Posted 3 years ago

Bürkert Pneumatic Control Valve Island interfaces with ET 200SP

Posted 3 years ago

Wave of success for new flowmeters"¦

Posted 3 years ago

Bürkert UK extends customisation and assembly service

Posted 3 years ago

Optimum level and flow control for food industry processes

Posted 4 years ago

Minimising waste in hygienic control valve applications

Posted 4 years ago

Seal of approval for Bürkert solenoid valves

Posted 4 years ago

How to choose a surface coating technology

Posted 4 years ago

Bürkert increases stock levels to support maintenance market

Posted 4 years ago

Do Food & Beverage SMEs need more process automation?

Posted 4 years ago

New light-weight precision flow meter suits process skids

Posted 4 years ago

Developing an alternative to Coriolis

Posted 4 years ago

Improving flow control in pneumatic conveying systems

Posted 4 years ago

Delivering on the requirement for ATEX control panels

Posted 4 years ago

Bürkert maintains price freeze for 2017

Posted 4 years ago

Bürkert offers fast delivery on full-bore mag flowmeters

Posted 4 years ago

Bürkert appoints new account manager for Ireland

Posted 4 years ago

Steam control valves: getting the most from this vital component

Posted 4 years ago

New networkable hygienic valve actuators from Bürkert

Posted 4 years ago

Pneumatic valves for SIL1 or SIL2 safety control systems

Posted 4 years ago

Bespoke process control systems for the food & beverage industry

Posted 4 years ago

Electromotive process valves deliver precision alternative

Posted 4 years ago

Clinical diagnosis benefits from design collaboration

Posted 4 years ago

Keeping control valves clean, inside and out

Posted 4 years ago

Hygienic 2-way bellows control valve for small flow rates

Posted 4 years ago

Upgrading process safety with compact control valves

Posted 4 years ago

Top 10 level-sensing technologies

Posted 5 years ago

Fast, reliable switching without pneumatics

Posted 5 years ago

Retrofit safety using innovative control valves

Posted 5 years ago

Bürkert launches Virtual Water Treatment Works

Posted 5 years ago

Building selective catalytic reduction systems

Posted 5 years ago

Emerging food preservation technology requires precision control

Posted 5 years ago

Precision gas control for experimental combustion rig

Posted 5 years ago

Electromotive process valves make compressed air obsolete

Posted 5 years ago

Meeting the demand for more complex process control systems

Posted 5 years ago

Bürkert cartridge valve is suitable for custom manifold designs

Posted 5 years ago

Developing new fluid management systems for in-vitro diagnostics

Posted 5 years ago

Bürkert launches hydroformed hygienic diaphragm valve

Posted 5 years ago

Bürkert improves functionality of ELEMENT controllers

Posted 5 years ago

Gas control for metal surface treatments

Posted 5 years ago

Measuring pH in a food-safe environment

Posted 5 years ago

Process control design - don't let ATEX restrict your plans

Posted 5 years ago

Bürkert application segmentation delivers across industries

Posted 5 years ago

Desktop autoclaves achieve reliability with Bürkert steam valves

Posted 5 years ago

Designs for controlling hot processes - it's all material

Posted 5 years ago

Controlling CIP / SIP in food processing applications

Posted 5 years ago

Energy saving with process valves

Posted 5 years ago

Solenoid valves - one for every occasion

Posted 5 years ago

Bürkert valve expertise delivers a premium shower experience

Posted 5 years ago

Control of water treatment with Bürkert multiCELL

Posted 6 years ago

Solenoid valves - some are more equal than others

Posted 6 years ago

Design & maintenance crucial to avoiding water hammer

Posted 6 years ago

Bürkert hazardous area-rated pneumatics in whisky bottling plant

Posted 6 years ago

Under Pressure - sensors in the spotlight

Posted 6 years ago

All new Bürkert website: cool tools, easy navigation and eShop

Posted 6 years ago

Bürkert helps to improve efficiency at UK car engine plant

Posted 6 years ago

Autoclave uses compact Bürkert process valves to meet targets

Posted 6 years ago

Free solenoid valve selection chart offered by Bürkert

Posted 6 years ago

Solenoid valves - an enduring design refined over time

Posted 6 years ago

Intelligent control for food processors

Posted 6 years ago

Bürkert's fluid control expertise now available direct to OEMs

Posted 6 years ago

Bürkert's multiCELL provides localised sensor signal management

Posted 6 years ago

Water control and analysis system with plug-in Sensor Cubes

Posted 6 years ago

Making the grade - achieving compliance with food standards

Posted 6 years ago

Bürkert releases new flowmeters for high-volume gases

Posted 6 years ago

Sensors 101: understanding sensors within a fluid control system

Posted 6 years ago

Modular valve body reduces energy needs and improves system flow

Posted 6 years ago

Sizing of pipework for steam applications for reliable operation

Posted 7 years ago

New valve body concept simplifies complex pipe interfaces

Posted 7 years ago

Design and components for pneumatic control automation systems

Posted 7 years ago

Improved functionality for batch controller and flow transmitter

Posted 7 years ago

Efficient bespoke effluent monitoring and batch control systems

Posted 7 years ago

Intelligent valve reduces pipework by switching multiple flows

Posted 7 years ago

Control signals - which option is best?

Posted 7 years ago

Steam expertise reduces costs in pet food production

Posted 7 years ago

Bürkert Technical Training to provide local options for 2014

Posted 7 years ago

Local development process delivers micro-fluidic valve systems

Posted 7 years ago

Electrically actuated quarter-turn valves for a range of options

Posted 7 years ago

Steam: how to manage it safely & efficiently

Posted 7 years ago

Free guide matches valves with chemical resistance properties

Posted 7 years ago

Fruit syrup production benefits from smart valve control

Posted 7 years ago

Tried and tested valve design nears 50 years of reliable service

Posted 7 years ago

Does your valve have the correct chemical resistance properties?

Posted 7 years ago

Microfluidics - micro dosing pump is precise and reliable

Posted 7 years ago

Integrated modular systems are key to precise gas handling

Posted 7 years ago

Bürkert improves control of water oxygenation

Posted 7 years ago

What's next in process control for the water treatment industry?

Posted 7 years ago

Retrofit control head enables automation of most process valves

Posted 8 years ago

Bürkert unveils new intelligent valve positioner

Posted 8 years ago

Bürkert reports excellent results from Total expo

Posted 8 years ago

Valves - when to repair or replace?

Posted 8 years ago

Bürkert launches new range of intelligent valve control heads

Posted 8 years ago

Seminar on valve innovation in the pharmaceutical sector

Posted 8 years ago

Free ATEX selection poster demystifies explosion criteria

Posted 8 years ago

Bürkert at Total Process & Packaging Exhibition 2013

Posted 8 years ago

New training brochure now available from Bürkert

Posted 8 years ago

Bürkert valves help TV science show with 360 degree swing

Posted 8 years ago

Direct-acting solenoid valves for fluids, gases, vacuum & steam

Posted 8 years ago

Free booklet for products and systems for producing clean steam

Posted 8 years ago

AS-I communication bus-equipped Element diaphragm valves

Posted 8 years ago

Bürkert UK officially opens the doors to its new UK headquarters

Posted 8 years ago

Fuel-cell race car relies on Bürkert valve technology

Posted 8 years ago

Bürkert Technical Training Schedule released for 2013

Posted 8 years ago

Burkert launches new butterfly valves

Posted 8 years ago

Burkert UK moves to new UK headquarters in Cirencester

Posted 8 years ago

Process valves that can "˜think' for themselves

Posted 8 years ago

AirLINE Quick valve island pneumatic system for process controls

Posted 8 years ago

Modern alternative to conventional variable area flow meters

Posted 8 years ago

Free Steam Site Guide aims to make steam systems safer

Posted 8 years ago

Design & Manufacture service for packaged batch controls

Posted 8 years ago

New multiCELL universal transmitter and sensor controller

Posted 8 years ago

Miniature valves for medical equipment reduce energy consumption

Posted 9 years ago

Three-tier approach for automation of hygienic processes

Posted 9 years ago

Free Select Catalogue provides faster fluid control deliveries

Posted 9 years ago

Multi-port valve interfaces meet life science plant requirements

Posted 9 years ago

Universal control head for hygienic processing industries

Posted 9 years ago

Flow transmitter and pulse divider combined in a single device

Posted 9 years ago

Express delivery for Namur interface valves from Burkert

Posted 9 years ago

Problem of contaminant ingress into diaphragm valves solved

Posted 9 years ago

Process automation quadruples brewery production

Posted 9 years ago

AirLINE Quick simplifies assembly of pneumatic control panels

Posted 9 years ago

Free training courses in Hygienic Processing

Posted 9 years ago

See Element process control products at Sensors + Systems

Posted 9 years ago

Digital flow transmitters are designed to be future-proof

Posted 9 years ago

Fountain control saves space, energy and money

Posted 9 years ago

Burkert extends Element range of process control components

Posted 9 years ago

Automated CIP saves pharmaceutical manufacturer £120,000 pa

Posted 9 years ago

PFA-lined stainless steel diaphragm valves resist corrosion

Posted 9 years ago

Type 2080 2/2-way valve with PTFE bellows for hygienic processes

Posted 9 years ago

Drinks manufacturer installs intelligent process valves

Posted 9 years ago

Multi-functional valve block for steam sterilisation systems

Posted 9 years ago

8175 ultrasonic level transmitter in IP65 or IP67 housings

Posted 10 years ago

Free courses: steam engineering and condensate management

Posted 10 years ago

Single controller for both process and proportional valves

Posted 10 years ago

Miniature solenoid valves specified for dosing machine

Posted 10 years ago

Element Neutrino analytical transmitters are more versatile

Posted 10 years ago

SideControl units achieve intelligent valve positioning

Posted 10 years ago

Customised ball valves used in fuel tank protection system

Posted 10 years ago

Burkert registers on Achilles Utilities Vendor Database

Posted 10 years ago

Ex-proof AirLINE Ex 8650 system chosen for North Sea project

Posted 10 years ago

Enamel-coated pH sensors offer advantages over glass types

Posted 10 years ago

Online monitoring of the reverse-osmosis systems

Posted 10 years ago

Control system replaces manual manufacturing process

Posted 10 years ago

Burkert appoints Fluid Controls as SE England distributor

Posted 10 years ago

How to save energy in hazardous area control systems

Posted 10 years ago

Miniature 3/2 isolation valve 'sets new benchmark'

Posted 11 years ago

Integrated liquid flow controller incorporates valve and sensor

Posted 11 years ago

Positioners/process controllers can mount on valve actuators

Posted 11 years ago

Spot welder 'tip off' detection using intelligent cooling system

Posted 11 years ago

Clever design halves the number of valves required

Posted 11 years ago

Compact flipper isolation valve delivers improved performance

Posted 11 years ago

Featured photo

Posted 11 years ago

Engine test rig benefits from globe valves and positioners

Posted 11 years ago

Valve and positioner provide test rig coolant control

Posted 11 years ago

Robolux valves eliminate deadlegs and save costs

Posted 11 years ago

Microfluidics offer benefits for automation and miniaturisation

Posted 11 years ago

Burkert and BBS-Systems partner for hygienic processing

Posted 11 years ago

New version of mxControl multi-parameter controller

Posted 11 years ago

New fluid control systems catalogue from Burkert

Posted 11 years ago

Bio-diesel processor developed with help from Burkert

Posted 11 years ago

Electrical and pneumatic systems in hazardous areas

Posted 11 years ago

Ultrasonic flow transmitter delivers long-term stability

Posted 12 years ago

Posted 12 years ago

Free Brewery Process Control brochure from Burkert

Posted 12 years ago

Burkert launches Element modular process control products

Posted 12 years ago

MicroFluidics catalogue of standard and bespoke systems

Posted 12 years ago

Pick-and-mix modular general-purpose solenoid valves

Posted 13 years ago

446-page catalogue covers all fluid control needs

Posted 13 years ago

More technical articles