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The MEC-RELA L20 series is a top-entry globe valve body construction with a wide range of different single stage trims available. L20 series combine an advanced modular design and the wide range of actuators to satisfy the needs of the industrial demand. L20 valves are designed to control a broad variety of fluids, like steam, water, most of the medium and gases. One of the main features of this series is the top guided construction that assure a stable plug travel over entire stroke of the valve minimizing vibration and wear.
The safe operation of this product is ensured only if it is installed, commissioned, used and maintained in an appropriate way by qualified personnel in compliance with the operating instructions.
Verify that the valve is suitable for the intended use and application by checking:
Mec-Rela valves are not intended to withstand any external stresses which can be induced by the systems in which they are inserted. The installer must take account of these stresses and take the appropriate measures to prevent them.
Ensure safe access and, if required, a safe working platform (with a suitable protection) is provided, before operating or installing the product. Arrange the suitable lifting means, if required.
Ensure the area around the valve is adequately lit and is suitable to safely work on the valve.
Take account of the content of the pipe (process fluid) or anything it may have previously contained. Take special safety precautions where flammable, hazardous substances are present, or where fluid pressure or temperature may be hazardous to health.
Take account of: areas at risk of explosion, lack of oxygen (such as tanks, wells, etc…), hazardous gases, temperature limits, high or low temperature surfaces, risk of fire (for example during welding operations), excessive noise, moving machines.
Wait until the temperature normalizes after the interception to prevent any risks of burn or freezing.
Take account of the possible effects on the whole expected working system. In particular, you must assess any proposed actions and the consequences that may result in any other part of the system, you must ensure the system remains safe at all times. Make sure that the control valve is isolated via shut-off valves to prevent any abrupt variations to the system.
Make sure that the pressure is isolated and discharged to the atmospheric pressure in safe condition. Take account of a double insulation (double block and vent) and the blocking or the labelling on the closed valves. Do not consider the system depressurized even if the pressure gauge indicates zero pressure. The depressurization process should include taking the valve through its full stroke, to ensure all pressure is allowed to exhaust to atmosphere. During the operation the valve is pressurized. Before performing any maintenance operation or action on the flanges and closing caps, make sure that the line is depressurized (0 bar) and at ambient temperature.
Before starting the work, make sure to have at your disposal all the tools required to perform it, do not make use of inappropriate tools. Use only Mec-Rela original spare parts.
Take account of whether you and/or others need some clothes against the hazards, such as chemical products, temperatures, radiations, noise, fall of objects, risks for eyes and face.
All works must be performed and supervised by some skilled, trained and competent personnel.
Use suitable lifting means for the handling of the products by assessing all the risks concerning the lifting, the environment load, the individual and the circumstances of the work which is about to be performed.
Protect the product in freezing environments where temperatures are lower than the freezing point of the process fluid.
During the operation, the external surface of the product can be at temperatures which are hazardous to touch. Take account of this risk.
The product should be disposed of in accordance with local legislation. This may be different in each State/Country/Nation. It is the users responsibility to dispose of the product according to local requirements.
Periodically verify any phenomena of internal and/or external corrosion and/or erosion as they may significantly damage the pressurized parts by locally reducing the thickness and as a consequence the safety degree.
The valve body casting is marked with an arrow showing the direction of flow and its normal flow path. The casting also has markings which show the type of material and maximum operating pressure. Before installing the valve, make sure that the inside of the valve is clean, by performing, if required, an energetic blowing with steam or compressed air. This should be done with caution. The installation of a filter (pos. A Fig. 1) upstream the valve will prevent dirt entering the valve. To allow periodical maintenance of valves that are installed on continuously operating systems, it is recommended to install two isolating valves, located upstream (pos. B Fig. 1) and downstream (pos. C Fig. 1) of the control valve, and a by-pass one (pos. D Fig. 1). Use the by-pass valve (pos. D Fig. 1) to manually regulate the process when the control valve is temporarily disconnected. The two shut-off valves must have the same internal diameter of the control valve. During the installation of the valve, make sure that the flow in the pipe goes in the same direction as indicated by the arrow on the valve body. The assembling position of the valve does not limit its operation, but it is recommended to assemble the valve with the actuator pointed upward (pos. E Fig. 1) as other positions may allow the accumulation of any impurities which are contained in the fluid thus damaging the valve itself.
To ensure a uniform load and a uniform alignment, the flange bolts must be gradually tightened in criss-cross sequence, as indicated in Fig. 2. Any excessive weight of the valve might damage the system structure. If required, support the valve by using suitable devices (Fig. 3) and/or ropes (Fig. 4).
The pneumatic actuator is provided with two 1/4" NPT connections, one of which is closed by a filter. Connect the control air pipe to the connection which has remained free. The control air must be clean, dry and free from oil and grease and must not exceed an allowed maximum pressure. The signal required to control the valve is provided on the plate fixed on the actuator’s yoke. If the valve is provided with a pilot positioner, refer to its manual.
For the connection of the electric actuator refer to its specific manual.
All operations described below must be performed and supervised by skilled, trained and competent personnel. The Mec-Rela valves are uniquely identified by a serial number fixed on the plate located on the actuator’s yoke. To order any spare parts or for any other need, always refer to the above-mentioned number. During operation the valve is pressurized. Before performing any maintenance operation or action on any pressure retaining part, make sure that the line is depressurized (0 bar) and at ambient temperature.
Separate the actuator from the valve (see section 6.3). In reference to the Fig. 6 and Fig. 8 for reverse action actuators and the Fig. 5 and Fig. 7 for direct action actuators, proceed as follow:
Separate the actuator from the valve (see section 6.3). In reference to the Fig. 9 for reverse action actuators and the Fig. 10 for direct action actuators, proceed as follow:
By referring to Fig. 11 (for valves 1/2” ÷ 4”) or to Fig. 12 (for valves 6” ÷ 8”) perform the following steps:
By referring to Fig. 13 perform the following steps:
By referring to Fig. 14 perform the following steps:
By referring to Fig. 15 perform the following operations:
By referring to Fig. 16 perform the following steps:
By referring to the figure corresponding to your packing gland model (from Fig. 17 to Fig. 24) perform the following steps:
The manual provides tables for tightening torques for different valve diameters and components:
The manual includes diagrams and dimensions for various valve sizes (1/2" ÷ 2", 3" ÷ 4", 5" ÷ 4") and closed plug types (M10x1.5 - 6g, M40x1.5 - 6g, M45x1.5 - 6g, M10x1.5 - 6g, M10x1.5 - 6g).
Every 24 hours after the first commissioning, check the connections to the pipe and especially ensure the flange bolts are tightened to the correct torque. Inspect the valve every year by verifying its wear and replacing any damaged parts. Periodically verify any phenomena of internal and/or external corrosion and/or erosion as they may significantly damage the pressurized parts by locally reducing the thickness and as a consequence the safety degree.
The manual lists available spare parts with their corresponding figure and position numbers:
The Mec-Rela valves are uniquely identified by a serial number fixed on the plate located on the actuator’s yoke. To order any spare parts or for any other need, always refer to the above-mentioned number.
General| Brand | Terranova |
|---|---|
| Model | MEC-RELA L20-A1 Series |
| Category | Control Unit |
| Language | English |
