K Controls "Knowledge"

K Controls is now featured in the Valve World Buyer's Guide

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Sub-sea valve position monitors specified for use on wave energy devices

K Controls sub-sea valve position monitors have been specified for use Aquamarine Power’s Oyster wave energy device that captures energy in near shore waves and converts it into clean sustainable electricity. The valves will control the flow of the high pressure water that is generated by the movement of the wave flap and associated hydraulic pistons and then moved onshore, via a pipeline, to drive a conventional hydro-electric turbine. Low pressure pipes will transport the water back from the hydroelectric power station to the wave energy device.

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There are a number of important application requirements:

• The position monitors have to be capable of being installed and commissioned sub-sea.
• They must be rated for continuous submersion at 15 metres depth.
• The feedback limits must be adjustable sub-sea and in such a way that dive times are minimised.
• Subsea connectors must meet an existing standard.
• Status indication must be provided and be visible to a diver.
• Extended life and reliability is required.

K Controls has been able to meet these requirements using a unit rated for submersion to a depth of 130 metres that has been widely used in the oil industry.

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It meets all of the clients requirements and can be calibrated remotely using the HART® protocol without diver intervention.

The field proven sub-sea position monitor has been used on applications that include:

• Monitoring the position of hydraulically actuated valves that flood the jackets on the legs of oil rigs during satellite guided positioning.
• Monitoring the position of failsafe valves on conventional tanker buoy mooring systems.
• Monitoring the position of valves in the ballast tanks of semi-submersible oil rigs.

Wave energy devices are important because the central aim of UK Government energy policy is to establish a supply of energy that is diverse, sustainable, secure and competitively priced. Ocean waves represent our planet's last untapped natural renewable energy resource. The energy contained within waves has the potential to produce up to 80,000TWh of electricity per year - sufficient to meet global energy demand five times over. Wave energy is, by its nature, a clean energy resource.  Aside from the energy expended in manufacture and installation of wave energy devices, it produces no carbon emissions.  In the future, subsea pipelines will connect multiple wave energy devices to a single onshore plant creating wave farms of several hundred connected devices generating hundreds of megawatts of electricity. The devices sit largely underwater so there is minimal visual impact.

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There is also a link between wave energy and desalination - the process of removing salt from water to produce freshwater.  Energy fuelled by diesel generators is currently used to pump high pressure saltwater over special membranes to produce freshwater. A wave energy device offers a cleaner, more cost-effective solution. It could be configured to produce high pressure saltwater direct to a desalination plant, without the need for any fossil fuels.

K Controls advert in the BVAA "Valve User" magazine

This advert is appearing in a number of editions of the BVAA "Valve User" magazine during 2013.

Download K Controls Advert

To visit the "Valve User" web page please click here

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Versions of the 007-100 and 007-120 are now available with ATEX, IECEx, cCSAus and INMETRO certification

The 007-100 and 007-120 Exd or Exia IIC Valve Position Monitors are now  ATEX, IECEx or INMETRO certified for use in gas Zones 1 and 2 and dust Zones 21 and 22. Exd and AExd versions are also available with  NEC 505 cCSAus certification marking for use in Canada and the USA. 

For Canada the products are gas certified Ex d IIC T6 and dust certified Ex tb IIIC, Class II, Groups E, F and G; IP66/IP67 or IP68. For the USA the products are gas certified Class I Zone 1, AEx d IIC T6 and dust certified Zone 21, AEx tb/tD T85^oC; IP66/IP67 or IP68. 

There are also versions for non-hazardous areas.

Download K Controls Spotlight on the 007-100 and 007-120 Position Monitors 2013 V 1.3

What is the difference between T class and T amb?

Does the "T" class of hazardous area equipment (e.g. T4, T5, T6) define the maximum temperature of the surrounding environment in which the equipment can be installed? For example in the case of T4 is the maximum ambient temperature 135ºC? 

We have been asked this question a number of times recently and the answer is "No".

The "T" class is interpreted in one of two ways:

1. The maximum surface temperature of the apparatus - In the case of T4 the maximum surface temperature of the apparatus must not exceed 135ºC degrees C.
2. The auto ignition temperature of a particular gas - The auto ignition temperatures of all the gasses in group T4 will be greater than 135ºC and less than 200ºC.  

The contents of the apparatus will increase the surface temperature of the apparatus when power is applied; during both normal operation and under fault conditions.

As an allowance needs to be made for this temperature rise, the maximum ambient temperature (T amb) of the apparatus can operate in also needs to be defined.

This maximum ambient temperature e.g.+ 40ºC or + 80ºC, will therefore be lower than the temperature defined by the relevant T class, e.g. 135ºC (T4).

A given piece of electrical equipment will therefore be approved for a stated range of ambient temperatures in which it is safe to operate.

Normally this would be T amb -20ºC to +40ºC, unless otherwise stated on the product certification. 

K Controls can offer certain products with a T amb as low as -60ºC or as high as +120ºC.

In summary you will need to know the T class and the T amb (maximum and minimum) in order to specify the correct equipment.

(For further information on the T class please click here).