Instructions and maintenance manual "A" type
- Machinery Directive: DIR 2006/42/EC (MACHINERY)
- Pressure Equipment Directive: DIR 97/23/EC (PED) ART.3, P.3
- Potential Explosive Atmospheres Directive: DIR 94/9/CE (ATEX) CAT.3 ZONE 2 and 22 GD.
Valve A complies with the Directive on Equipment and Protective Systems for Potentially Explosive Atmospheres. In these cases the logo will appear on the identification label. This label shows the exact classification of the zone in which the valve can be used. The user is responsible for its use in any other zone.
When handling the equipment please pay special attention to the following points:
To prevent damage, especially to the anticorrosive protection, it is recommended to use soft straps to lift the CMO knife gate valves. These straps must be fitted to the top of valve, around its body. Do not lift the valve or hold it by the actuator. Lifting the valve by the actuator can lead to operating problems as it is not designed to withstand the valve's weight. Do not lift the valve or hold it by the flow passage area. The valve's O-ring seal is located in this area. If the valve is held and lifted by this area it can damage the surface and the O-ring seal and lead to leakage problems whilst the valve is operating. Safety warning: Before handling the valve check that the crane to be used is capable of bearing its weight.
In order to avoid personal harm and other type of damage (to property, the plant, etc.) please follow these recommendations:
The staff responsible for the handling and maintenance of the equipment must be qualified and trained in operations with this type of equipment. Use appropriate personal protection (gloves, safety boots, goggles, helmet, reflective vest…). Shut off all operating lines to the valve and put up a warning sign. Completely isolate the valve from the whole process. Depressurise the process. Drain all the line's fluid through the valve. Use hand tools not electric tools during the installation and maintenance, in accordance with EN13463-1(15).
Before installation, inspect the valve body and components for any possible damage occurred during transport or storage.
Make sure that the valve's inside cavities are clean. Inspect the pipes and the flanges to make sure they contain no foreign material and are clean.
The valve is unidirectional and an arrow is marked on the body indicating the flow direction.
The word SEAT is also marked on one side of the body (near the packing gland) to indicate the side where the sealing joint is located.
As a rule, when the valve operates with clean liquids or with low solid content it is recommended to install it so that the pressure pushes the gate against the seat. That way, the fluid direction will be the same as the direction indicated by the arrow on the body (Fig. 1).
Special care must be taken to maintain the correct distance (gap) between the flanges and ensure they are correctly aligned and parallel (Fig. 3).
The incorrect position or installation of the flanges can cause deformations on the valve's body which can cause difficulties during operation.
It is very important to make sure that the valve is correctly aligned and parallel to the flanges to prevent leakages and avoid deformations.
The screws in the tapped blind holes will have a maximum depth and will never reach the bottom of the hole.
The following table shows the maximum thread depth in the holes and the maximum torque to be applied to the screws when the valve is installed between flanges:
Assembly positions (Horizontal Pipe)
CMO valves can be assembled in all positions; however, recommendations do exist for some of them.
- Position 1 : This is the most advisable position.
- Positions 6, 7 and 8 : The valve can be installed in this position but you are advised to contact CMO if this is necessary.
- Positions 2, 3, 6 and 7 : For standard valves larger than ND200 and maximum angle permitted with the vertical of 30º. For sizes smaller than ND250 the angle can be increased up to 90º. This knife gate valve has no gate guides on the sides and the larger the valve the heavier the gate. In these positions, the gate can rub against the body during operation and stop it. For that reason it is a very important point to consider.To install valves larger than ND200 in any of these positions please contact CMO. In these positions it is recommended to secure the actuator to prevent the shaft from bending due to the weight of the actuator. If this is not carried out it could lead to operating problems.
- Positions 4 and 5 : For valves larger than ND200 please contact CMO. For sizes smaller than ND250 the valves can be installed in these positions. This knife gate valve has no gate guides on the corners and the larger the valve the heavier the gate. In these positions, the gate can rub against the body during operation and stop it. For that reason it is a very important point to consider. To install valves larger than ND200 in any of these positions please contact CMO. In all these positions it is recommended to secure the actuator to prevent the shaft from bending due to the weight of the actuator. If this is not taken into account, it can lead to problems during the valve's operation.
Assembly positions (Vertical/Inclined Pipe)
CMO valves can be assembled in all positions; however, recommendations do exist for some of them.
- Position 1 : The most advisable position.
- Position 5 : The valve can be installed in this position but you are advised to contact CMO if this is necessary.
- Positions 2, 3 and 4 : In these positions it is recommended to secure the actuator as its weight can cause the shaft to bend. If this is not taken into account, it can lead to problems during operation. Once the valve has been installed, check that all the screws and nuts have been correctly tightened and that the whole valve action system has been correctly adjusted (electrical connections, pneumatic connections, instruments…). Even if the valve has been assembled and tested at CMO’s facilities, during the handling and transport the screws on the packing gland tend to come loose and must be re‐tightened. Once the valve is installed in the pipeline and it has been pressurised, it is very important to check for any leakages from the packing gland to the atmosphere. In the event of a leakage, tighten the screws on the packing gland crosswise until the leakage stops, ensuring that there is no contact between the packing gland and the gate. A very high tightening torque on the packing gland's screws can lead to problems, such as an increase in the valve's torque, reduction in the packing's working life, or the breaking of the packing gland. The tightening torques are indicated in the following table:
|Tightening torques for packing gland screws|
ND50 to ND125
ND150 to ND300
|ND350 to ND1200||35 Nm|
Once the valve is installed in its place, check that the flanges and electrical and pneumatic connections are secure. If electrical connections are present or you are in an ATEX zone, earth connections must be made before starting.
In an ATEX zone, check the continuity between the valve and the pipeline (EN 12266‐2, annex B, points B.2.2.2. and B.2.3.1.). Check the pipeline's earth connection and the conductivity between the outlet and inlet pipelines.
Handwheel (Rising or Non-Rising Stem and Stem with Gear Box)
To operate the valve: We can turn the handwheel clockwise (close) or anticlockwise (open).
To operate the valve pull one of the chain's vertical drops downwards, to lock it with the other one, remembering that opening is clockwise.
First loosen the position locking clamp located on the yoke. Once it is unlocked raise the lever to open or lower it to close. To complete the operation lock the lever again.
Pneumatic (Double and Single Acting), Hydraulic (Double and Single Acting)
This actuator can be manually operated (via pushbuttons), and automatically operated via various sensors, detectors, timers...
Motorised (Rising or Non-Rising Stem and Stem with Gear Box)
This actuator can also be operated manually or automatically, each different type of actuator will have its own instructions.
In order to avoid personal harm and other types of damage (to the plant, etc.) please follow these recommendations:
The staff member responsible for the installation, operation and maintenance of the valves must be qualified and trained in the operation of similar valves. Appropriate personal protection must be used (gloves, safety boots, goggles, helmet…). Shut off all operating lines to the valve and put up a warning sign. Completely isolate the valve from the process. Fully depressurise the process. Drain all the line's fluid through the valve. Use hand tools not electric tools during the installation and maintenance, in accordance with EN13463‐1(15).
The only maintenance required in this type of valve is to change the seat's rubber joint (if soft seated valve is used) and the packing. It is recommended to check the seal every 6 months, however its working life will depend on the valve's operating conditions, such as: Pressure, temperature, number of operations, fluid composition, among others.
In an ATEX zone, electrostatic charges may be present inside the valve, which can cause explosions. The user is responsible for minimising the risks.
- The maintenance staff must consider the risks of explosion and ATEX training is recommended.
- If the fluid transported constitutes an internal explosive atmosphere, the user must regularly check the installation's correct watertight integrity.
- Regular cleaning of the valve to prevent accumulation of dust.
- Assemblies not permitted at the end of the line
- Avoid painting the products supplied.
Replacing the sealing joint (Watertight Valves)
- 1- Remove the valve from the pipeline.
- 2- Remove the actuator and safety guards by unscrewing and removing the bolts connecting the stem to the gate and the support plate to the body
- 3- Remove the packing gland (3).
- 4- Remove the old packing (8) taking care not to damage its O-ring.
- 5- Remove the gate (2) carefully without losing the nylon slides (7).
- 6- Clean the inside surfaces of the valve.
- 7- Remove the ring (5) that secures the sealing joint (6). For this purpose, apply a few sharp knocks to the outside with a bronze object at the base of the ring until it comes out.
- 8- Remove the old sealing joint and clean its housing.
- 9- Fit a new sealing joint (6) with the same dimensions as the old one or use the dimensions given in Table 3 below.
- 10- Insert the retaining ring (5) in its original position as indicated: place the retaining ring in perfect alignment parallel to the sealing joint, push the ring as a whole towards the base of the channel, check that all areas of the ring are correctly inserted, in perfect contact with the valve and the joint has not been damaged in the process.
- 11- The valve assembly will be performed in exactly the opposite way to the disassembly.
Note : During the assembly of the new sealing joint it is recommended to apply “Vaseline” to the seal to facilitate the assembly process and the valve's correct operation (do not use oil or grease), below, we show details of the Vaseline used by CMO:
|White petroleum jelly|
Melting point (ºC)
|Viscosity at 100ºC||ASTM D-445||5|
|Penetration 25ºC mm./ 10||ASTM D-937||165|
Replacing the sealing joint (Teflon or PTFE)
The following aspects must be considered:
- To obtain greater watertight integrity in the stainless steel bodies it is advisable to apply plastic glue to the joint housing. If the body is painted this is not necessary.
- With the rubber seal tab pointing outwards, make a circle and then form a heart shape.
- It is recommendable to insert the joint in the top part, press the arched part and insert the seal into the housing.
Replacing the packing
- 1- Make sure there is absolutely no pressure and fluid in the installation.
- 2- Place the valve in open position.
- 3- Loosen the screws that connect the stem or rod to the gate.
- 4- Release the connection between the support plate and the body.
- 5- Release and remove the packing gland (3) and the safety guards where present.
- 6- Remove the damaged packing (8) using a pointed tool, taking care not to damage the surface of the gate (2).
- 7- Carefully clean the packing box and make sure there are no metal parts inside.
- 8- Insert the new packing (8). During this operation it is very important for both ends to be perfectly joined. Below we show the packing dimensions (Table 5). As standard, CMO valve packing is composed of 3 lines (2 packing lines and 1 rubber joint line in the middle). If it is not possible to place a rubber joint in the middle another packing line should be used instead.
- 9- Place the packing gland in its original position (step 5), making sure it does not touch the gate, carefully tighten all the screws crosswise and make sure the same distance is left between the gate and the packing gland on both sides.
- 10- Assemble steps 3 and 4.
- 11- Perform one manoeuvre slowly, stopping if any seizing occurs. If this occurs the packing gland has not been centred correctly.
- 12- Pressurise the valve in the line and tighten the packing gland crosswise, enough to prevent leakages to the atmosphere.
2 lines of 8 mm² x 204 mm.
|1 line of 8 mm² x 204 mm.|
2 lines of 8 mm² x 234 mm.
|1 line of 8 mm² x 234 mm.|
|ND80||2 lines of 8 mm² x 264 mm.||1 line of 8 mm² x 264 mm.|
|ND100||2 lines of 8 mm² x 304 mm.||1 line of 8 mm² x 304 mm.|
|ND125||2 lines of 8 mm² x 356 mm.||1 line of 8 mm² x 356 mm.|
|ND150||2 lines of 8 mm² x 406 mm.||1 line of 8 mm² x 406 mm.|
|ND200||2 lines of 10 mm² x 516 mm.||1 line of 10 mm² x 516 mm.|
|ND250||2 lines of 10 mm² x 636 mm.||1 line of 10 mm² x 636 mm.|
|ND300||2 lines of 10 mm² x 740 mm.||1 line of 10 mm² x 740 mm.|
|ND350||2 lines of 10 mm² x 810 mm.||1 line of 10 mm² x 810 mm.|
|ND400||2 lines of 10 mm² x 928 mm.||1 line of 10 mm² x 928 mm.|
|ND450||2 lines of 10 mm² x 1 028 mm.||1 line of 10 mm² x 1 028 mm.|
|ND500||2 lines of 14 mm² x 1 144 mm.||1 line of 14 mm² x 1 144 mm.|
|ND600||2 lines of 14 mm² x 1 346 mm.||1 line of 14 mm² x 1 346 mm.|
It is recommended to lubricate the stem twice a year by removing the protection cap and filling it with grease up to half its volume.
After the maintenance is complete, in an ATEX zone it is obligatory to check the electrical continuity between the pipeline and the rest of the installation's components. EN 12266‐2, annex B, points B.2.2.2. and B.2.3.1.)
To ensure the valve is in optimum conditions of use after long periods of storage, it should be stored in a well‐ventilated place at temperatures below 30ºC.
If it is stored outside, the valve must be covered to protect it from heat and direct sunlight, with good ventilation to prevent humidity.