Dating back to 1918, ARCA Regler has earned global recognition for specialising in control valves, manufactured and marketed around the world primarily for the chemical, food, power, petrochemical, steel, pharmaceutical and oil and natural gas industries.
ARCA’s Ecotrol control valves: committed to perfection in every detail
ARCA’s Ecotrol range offers a wide variety of innovative solutions designed to fulfil all control task requirements. Whether housing, inner valves, valve seats, stem seals, actuators, or positioners, every detail benefits from the know-how of expert engineers with many years’ experience in a wide range of applications. Factors such as efficiency, control precision, price/performance ratio, weight, and lifecycle costs are all optimised to suit user requirements in order to deliver high control precision and lower operating costs.
Ecotrol offers a wide range of process tailored valve internals, including standard parabolic plugs (either metal seated or with the patented ARCA soft seal system), multistage low-noise perforated as well as double-guided valve plugs.
High-performance valve actuator
The pneumatic multi-spring actuators, with robust construction and integrated explosion protection, are characterised by short actuating times, optimised actuating forces, and reliable tight sealing. Valves are also available with electric or electrohydraulic actuators.
The ARCAPRO digital positioner is a multi-functional interface with integrated bus support for the controller or process control system. Installation and mechanical connection to the valve actuator are compliant with VDI/VDE 3847 guidelines for open, non-proprietary concepts.
Reliable stem seals
From the stuffing box to the hermetically-sealed bellows, this stem seal can be tailored exactly to the process fluid, pressure and temperature required. The design, stem surface and packing material complement each other perfectly to avoid problems with friction, corrosion and emissions.
Fixed-form housing seal
The design connects the valve housing and the bonnet in force bypass and the seal is clamped in place preventing it from yielding. This housing/bonnet design also ensures that the valve seat and plug are not subject to any lateral forces, which helps prevent leakage.
Robust, high-precision valve trims
These are specially designed for the prevailing flow conditions in a plant. The shapes of the throttle valves and seats, and the materials from which they are made, are optimised to meet user requirements. Valve seats integrate the unique quick-exchange system and can be replaced without special tools. The float-mounted clamping seat and the metal or soft seal for the valve seat ensure leak-tight, reliable sealing.
Ecotrol in action
A number of ARCA Ecotrol control valves were supplied on a project to Sasol South Africa a few years ago, including the 28” (DN 700) Ecotrol valve
seen on the cover. These valves stand some 3 m tall and weigh 5100 kg.
On another project ARCA Flow Controls in Houston, Texas, the US subsidiary of ARCA Valves Germany, recently received an order for the delivery of several large anti-surge control valves. The specialised valves, designed for several compressor lines in Mexico, went online early in 2018.
The anti-surge globe-type control valves were designed from the proven Ecotrol modular parts system and tailored to prevent the compressors from pumping under stressful conditions in the plant. They also prevent any disruption at the compressor blades in order to preclude damage.
Integrated in the bypass section of turbo-compressors, the valves reliably carry out multiple tasks simultaneously, for instance, assisting during the start-up and shut-down phases of the compressor. Excess amounts of gas are diverted or blown off at critical points, or when the machine must be kept operating at constant speed as consumption fluctuates. The most important function, however, is that of a safety valve as used to provide protection for the compressor stage. Proven ARCA valves reliably prevent pumping action when a stall is encountered or a minimum flow rate is undershot.
The compressor lines in Mexico each consist of one single-screw compressor driven by a gas turbine. Two lines were installed in a pipeline station in La Laguna in the Mexican federal state of Coahuila. The other three lines are at a pipeline compressor station in Villa de Reyes in the federal state of San Luis Potosi.
The pipelines will deliver natural gas to CFE (Comisión Federal de Electricidad) power stations as well as industry plants. The compressor station’s output serves a pipeline of about 1500 km, which transports the natural gas from the north into the country’s interior.
When choosing the anti-surge valves, various things were considered including ARCA’s vast application knowledge and reliability record, as well as the easy to maintain clamping seat design. ARCA offers advanced solutions for anti-surge control valves and the continuous development of the Ecotrol modular parts system further satisfies the growing demands of the compressor manufacturers’ market. A high flow rate, low noise level, fast reaction times, as well as high control accuracy, are among the many advantages of this modular valve system.
The ARCA Flow Group: a never-ending search for a better solution
The success of the ARCA Flow Group builds on an innovation that was filed for patent protection by Ragnar Carlstedt back in 1917. Today, this spirit lives on and has become an inseparable part of the organisation’s history and corporate culture. The ARCA group includes ARCA ARTES, von Rohr, WEKA and Feluwa. In 2017 / 2018 ARCA celebrated the one hundred year anniversary of the ARCA patent and of the company foundation.
All the answers for perfect control
In addition to the products of the Ecotrol range ARCA’s expertise extends to the design and manufacture of a variety of control solutions as demonstrated in its numerous patents.
The extent of this expertise is ably demonstrated in the variety of valve and actuator solutions available for high pressure, angle pattern, pressure reducing, and desuperheater applications:
• High pressure: in all thermodynamic processes ARCA three-way valves are applied for example in high pressure applications for transferring, compressing and pre-heating stations, as well as in overheating processes in power stations. In use for several years now, these valves have demonstrated excellent performance, delivering long service life under the harshest operating conditions. Furthermore, they can be applied in gas pipeline systems.
• Angle pattern: ARCA developed its angle valve series for use in difficult working conditions. In sonic relevant applications, for instance, it is often recommended to use angular valves because the flow of the medium is turned only once by 90°, contrary to single or double seated valves. The process medium flows into the angle control valve from the side or the bottom and exits after just one deflection.
• Pressure reducing: pressure controllers of ARCA’s Roboter series can be used anywhere pressures of fluids, gases and steams are to be kept constant. Special features include the flexible adaptation of measuring range and the variety of mounting options. The reversible actuator of these pneumatic control valves enables the choice of safety function for the control plant (spring to close/open).
• Desuperheater: in contrast to other valves that operate according to the stroke principle, ARCA’s desuperheater utilises quarter-turn movement. As the valve stem is turned, the ball contour located directly behind the water connection opens and flow to the desuperheater lance is enabled. Water flows through the hollow stem and reaches the nozzles through openings designed in such a way that there are no ‘steps’ in the characteristic transfer curve. By using nozzles with different bore diameters, any characteristic curve can be realised – fine-tuned to the user’s application.
Other innovations that round out the valve programme from ARCA include:
• Modular parts system with standardised components.
• Flow-optimised housings.
• Optimised valve trim comprising cones and seats for all applications.
• Standardised interface to valve actuators.
• Valve trims can easily be completely removed and plugs and stems replaced.
|Tel:||+27 31 579 2593|
|Fax:||+27 31 579 2562|
|Articles:||More information and articles about Valve & Automation|
© Technews Publishing (Pty) Ltd | All Rights Reserved