Why Specify CLA-VAL Automatic Control Valves?

Introduction
Control valves form an essential part of the effective and efficient operation of any pipeline system. Selection of these devices are highly dependant on the personal experience of the engineer, the detail in manufacturer's product literature and published imperical data. It is often assumed, due to the lack of published field data that at the least, all control valves are the same in performance. Control valves for this reason, are often specified based on the desired function or, for a perceived advantage which may in essence have no bearing on the valve's effectiveness.
As an integral component to any pipeline system, control valves should be selected as with all other pipeline components on the cost of ownership which implies weighing up the initial cost of the valve against; maintenance, requirements, ease of installation, effectiveness of operation, availability of spares and, technical support and after sales backup.
Cla Val, when assessed against these requirements and for the reasons outlined below, is the most obvious choice for all your control valves needs.

The CAL-VAL difference

Low Flow Conditions
Low flow conditions cannot be accommodated for in conventional control valves without the addition of paraphernalia such as Vee Ports and the like that may present additional operational problems. Alternatively, expensive changes to the pipeline are recommended such as installation of reducing pieces and smaller diameter valves or, installation of low flow bypasses. Model 600 Cla-Val Hytrols provide a cost effective and efficient reduced port design to cope with low flow conditions.

Resistance to Cavitation Damage
High pressure drops or excessive flow conditions will inevitably cause cavitation which result in high noise, excessive vibration and damage to the valve. Designs utilising Vee Ports do not prevent but aggravate this destructive phenomenon. The use of multiple orifice plates is often not practical in applications where there is limited space; in addition, the solution is removed from the valve and can lead to error in application.
The specific design of the model 600 Cla-Val with its enlarged flow area around the seat allows for vapour bubbles to slow down before disposing against the walls of the valve housing, reducing potential cavitation damage. A ratio of 4 to 1 reductions in pressure can be maintained without damage.
In addition, Cla Val provides a proven, radial design cartridge that can be fitted to its standard hytrol design for severe applications. High Differential Pressure Applications
The stem of a control valve is often subjected to high differential pressures. Stems of Wye (Y) Pattern (sometimes called semi-straight) designs are centrally guided. The inclined operation of the stem in addition to its central guidance often leads to excessive wear of the o-ring seals and bearings and subsequent leaks. Vee Ports, which may cause a number of operational problems, are often specified to provide more controlled guidance to the stem.
The Cla-Val non-magnetic stem as standard is fully guided through its complete stroke by two
replaceable bearings.

Sensitive and Critical Flow and Pressure Set Points.
Pilot control systems form the heart of any control valve design. Most manufacturers provide a limited selection of pilot controls or, make use of three way controls which result in inaccuracy in control due to the shifting of the control point.
The two-way modulating control systems manufactured by Cla-Val are designed to minimise set point fluctuations. Stem movement of these controls are limited to one-mm, hence the spring is compressed by one-mm maximum, and the modulus of the spring does not change over this distance of compression, resulting in the set point remaining constant. Cla Val in addition provides the widest selection of control systems.

Ease of Maintenance
It is prudent, regardless of design, to maintain control valves regularly. Large diameter, Wye (Y) pattern valves are difficult to maintain due to the bonnet installed at an angle.
Cla-Val utilises a globe pattern design and has only moving part which makes for ease of maintenance.

Local Manufacture
Cla-Val has been available in South Africa since 1977 and has been locally manufactured, under licence to Cla-Val Co., by Dynamic Fluid Control (Pty) Ltd since 1981.
The local market, because of this relationship has access to more than sixty five years of global experience in real world and demanding control valve operation in applications such as waterworks distribution systems, fire protection systems, farm irrigation, navy ship systems, ground fuelling and industrial fluid handling systems. In addition, the market is updated and kept on the edge of technological advancement in electronic and hydraulic control systems through Cla-Val's Co's aggressive and continued research and development programme.

Sales and Field Service
Cla-Val provides highly committed customer orientated sales, service, spares and technical back up -

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