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SIMPLE GUIDELINES - MULTIPLE ADVANTAGES

Whenever shut-off or control applications involve abrasive or corrosive slurries, powders, or granular substances, the Larox Valve is the optimum solution. The modern pinch valve technology offers substantial savings through superior performance, longer service life time and low maintenance costs.

The Larox Valve consists of three main components: sleeve, valve body, and actuator. The versatile construction of the Larox Valve enables a customer to choose any actuator, valve body construction or sleeve material according to their process conditions. The variety of combinations is almost unlimited.

The standard range of Larox Valve solutions is for diameters 25 mm - 1000 mm, temperatures -50 C - +110 C, and pressures 0 - 100 bar. In co-operation with the customers Larox can engineer a solution to solve problems in applications outside the standard Larox product range.

On this page You will find information about following subjects:

Advantages of Larox valves
Valve sleeve
Continuous quality improvement
Valve bodies
Actuators for every need


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      Advantages of Larox valves

      High wear resistance
      The valve sleeve is the only part in contact with the fluid flow. By selecting the right elastomer quality according to the flowing medium the highest resistance against abrasive and corrosive conditions can be achieved.
      Trouble-free operation
      The valve sleeve is not affected by encrustation or hardening due to scaling liquors. Any encrustation will separate itself from the elastic surface of the sleeve in the course of normal use, and will not prevent opening or closing of the valve.
      Low flow resistance
      In the fully open position, the sleeve of a pinch valve becomes an integral part of the straight pipeline. The full bore solution ensures an unobstructed flow essential for coarse slurries.
      The unique design of Larox valves also ensures low flow resistance. The advantageous flow properties reduce considerably power loss in the pipework which means savings on the pumping costs.
      Excellent control properties
      The control curve of Larox pinch valves is nearly linear which corresponds to wide and accurate control range.
      Low cost spare parts
      The only wearing part of the Larox valve is the elastic sleeve. It can be replaced using standard tools without special training or costly machining operations. Periodic sleeve replacements guarantee reliable and undisturbed operation in critical applications.
      Modular structure
      The Larox pinch valve has a modular structure which gives our customers the possibility to choose any actuator, body, or sleeve type according to their needs.
      Remarkable investments in R & D
      The Larox engineering service is continuously developing and testing new materials and equipment in cooperation with their customers to expand the operational range of Larox pinch valves.

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    Larox valve sleeve - the best sleeve available

    The valve sleeve is the only part in contact with the product flow. The selection of the sleeve material is very essential to guarantee the best wear resistance and longest lifetime for the valve sleeve and a trouble-free function of the process. The properties of the modern elastomer sleeves have many advantages compared to the conventional metal parts: rubber is elastic, waterproof, airtight and has considerably better wear resistance than steel. Additionally, the elastomer sleeve provides a low cost solution against many chemicals when compared to more expensive steel materials.

    The pinch valve sleeves have a thick wear resistant inner lining, several textile reinforcing cord layers and a wear resistant outer surface. The process conditions such as pressure class, application, medium, and temperature determine the final selection of the valve sleeve material.

    The Larox valve sleeve materials range from wear resisting natural rubber to various elastomers and rubber compounds developed to combat the arduous conditions in chemical processing.

    The Larox valve sleeve can be supplied with positive opening tags. The opening tags guarantee undisturbed opening of the valve in high temperatures, low pressures and vacuum conditions as well as in situations where the valve has been closed for a longer period of time.

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    Continuous development and testing results in high quality products

    Larox Flowsys Oy and its sleeve manufacturing partner, Teknikum Oy, are continuously testing and developing the valve sleeves in order to find new materials and elastomer compounds to enlarge the operational range of Larox valves to even more aggressive and difficult applications. The Larox brand sleeves are manufactured in accordance with ISO 9001 quality specifications. The whole manufacturing chain of the Larox valve sleeve is controlled by Teknikum Oy. The product control covers all stages starting from the purchase of natural rubber through mixing the compounds to the final sleeve construction and vulcanizing.

    The reliability of the Larox valve sleeve is taken into account already when designing the sleeves. The safety factor for the valve sleeve is adjusted to 3 which means that the bursting pressure of the sleeve is 3 times the operating pressure. Because of this factor, the testing of the valve sleeves is restricted to normal random sample inspection. However, Larox Flowsys has complete testing facilities to fulfill any customer requests related to the valve testing procedures.

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      VALVE BODY TYPES


      PV OPEN BODY

      The open body construction is designed for applications with relatively low pressures and low temperatures when the flowing medium is non-hazardous. The open body construction is light and it is very easy to access for service.

      The available valve diameters begin with 80 mm. The standard body material is mild steel, but AISI316 bodies can also be delivered upon request.

      The open body offers the advantage of being able to tolerate misalignment and vibration.

      PVE ENCLOSED BODY

      In the enclosed body construction the valve sleeve is covered by the body housing which protects the sleeve from the environment and sun shine. The enclosed body keeps the flowing medium inside even though the sleeve has been ruptured.


      The available body materials are cast iron/mild steel, aluminum and AISI316.

      PVE/S

      The enclosed body construction can also be used in applications where fugitive emission protection is specified. This enclosed PVE/S valve is equipped with a fugitive emission package that includes the stem and body seals to provide a secondary containment of the fluid in the valve and leakage to the outside environment from the valve body.

      The valve body is equipped with a tap in the lower half of the valve body with a threaded AISI 316 plug. Additionally available is a gauge indicating the pressure changes in the valve body. The standard body materials are cast iron/mild steel, aluminum and AISI316.

      PVS SEALED BODY

      The sealed body construction is designed for applications where no leakage of the flowing medium through the valve body is allowed to the environment. The PVS model has proved especially successful in high pressure applications due to the extremely resistant body construction. The sealed body can be equipped with an alarm or piping to ensure that the sleeve rupture can be noticed immediately.
      The PVS structure has no rising parts outside the body. The body materials can be chosen from cast iron/mild steel, aluminium or AISI316.

      All the valve bodies are flange ended. The standard flange drillings are according to the DIN, ANSI, and BS/AS standards. Any special customer requirements can be accomplished upon request.

      The Larox valves close on center line to maximize the sleeve life time and provide better control in modulating or throttling applications.

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      ACTUATORS FOR EVERY NEED

      MANUAL ACTUATORS (M)

      The manual valves are equipped with a handwheel actuator. The screw mechanism of the manually operated valves is totally enclosed, and thus protected against dirt and corrosion to ensure reliable operation.

      The large diameter manual valves and the valves used in high pressure applications come equipped with a reduction gear to ease the operation. Manual valves can also be fitted with a chain wheel and extended stem.

    WIDE VARIETY OF PNEUMATIC ACTUATORS (A)

    The pneumatic actuator is a double acting cylinder. The standard supply pressure for the pneumatic cylinder is min. 6 bar. The cylinder size is determined according to the process line pressure.

    The pneumatic actuator is also available in special materials for aggressive conditions.

    Pneumatic actuator with manual override (AB)
    The valve can be equipped with a manual override to ensure that in malfunction situations such as a loss of air supply the valve can be closed with the handwheel.
    Pneumatic actuator with pneumatic spring (AU))
    The pneumatic spring ensures that the valve can be opened or closed if the supply pressure is suddenly not available. The valve can be opened or closed only once in the malfunction situation and the function is dependable for 1 - 2 days. The pneumatic spring can be operated through a separate or an integrated air tank. In most situations, the more expensive mechanical spring can be replaced with the pneumatic spring.
    Pneumatic actuator with mechanical spring (AV))
    Single acting pneumatic actuator provided with a mechanical spring to close or open the valve.

    Control valve actuators

    Pneumatic actuator with pneumatic positioner (AN) )
    The standard pneumatic positioners in the Larox valves are Neles, PMV or Apex positioners. The standard incoming signal is 0.2 - 1 bar and the increasing signal closes the valve.
    Pneumatic actuator with electro-pneumatic positioner (AK))
    The standard electro-pneumatic positioners are Neles , PMV or Apex positioners. The standard incoming signal is 4-20 mA and the increasing signal closes the valve.

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      HYDRAULIC ACTUATORS (H)

      The hydraulic actuator is a double acting cylinder. The standard supply pressure for the hydraulic cylinder is min. 150 bars. The final cylinder size is determined according to the line pressure.

      The standard cylinder is equipped with a pilot operated check valve which keeps the valve in position when hydraulic pressure is not available.

      Hydraulic actuator with electro-hydraulic positioner (HP))
      For demanding flow control the hydraulic actuator can be delivered with an electro-hydraulic positioner. The standard incoming signal for the electro-hydraulic positioner is 4-20 mA

      The Larox valve product range includes also hydraulic power packs to actuate the hydraulic valves. Tailor made solutions are available upon customer requests.

      ELECTROMECHANICAL ACTUATORS (E)

      The standard electromechanical actuator types are AUMA Norm SA-series and Rotork IQ-series actuators equipped with build-in limit switches and manual handwheel. The standard voltage is 380V 50Hz, others on request.

      Electromechanical actuator with electronic positioner (EO)
      The standard actuators are Auma Norm SA-series with RWG, Auma Matic SAM series or Rotork IQ-series. The standard incoming signal for the electromechanical positioner is 4-20 mA. All electromechanical actuators are supplied complete with manual override.

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