IOM -
SELF-ACTING DIAPHRAGM VALVES
MAXOMATIC VMXBERL24C
©COMEV
AL
V
A
L
VE SYSTEMS
T
echnical Dept. Ref. IOM-SELF-ACTING DIAPHRAGM V
A
L
VES, MAXOMA
TIC VMXBXERL24C-Ed.15/05
Comeval V
alve Systems reserves the right to alter any technical data contained in this Manual without prior notice. Regularly u
pdated data on www
.comeval.es
Herewith a chart summing up available functions:
4 WAY VALVE
POSITION
SOLENOID VALVES POSITION
ACTION
24V DC type
Latch type
CLOSE
ON/OFF
ON/OFF
Main valve closes irrespectively of PRP and solenoid valves
AUTO
OFF
ON/OFF
Main valve closes irrespectively of PRP
ON
ON/OFF
Main valve controlled by PRP
OPEN
ON/OFF
OFF
Main valve closes irrespectively of PRP
ON/OFF
ON
Main valve controlled by PRP
Main Valve working as Pressure Reducing Valve:
The valve is working to reduce the upstream pressure and maintain a constant preset downstream pressure, constantly
responding to upstream pressure & fl ow fl uctuations. When downstream pressure is under preset pressure, the Main
Valve opens to increase it (the Pilot allows the discharge of top chamber). When downstream pressure is above preset
pressure, the main valve closes to decrease it (the Pilot allows the fi lling of top chamber).
In static conditions, with no fl ow, the Main Valve fully closes when downstream pressure is above preset downstream
value. Downstream pressure can slightly increase above preset pressure due to valve response time, so this must be
taken into consideration.
Pressure Reducing Pilot adjustment:
With working mode 2.1 or 3.1:
To increase the preset downstream pressure, turn the Pilot adjusting screw clockwise.
To decrease the preset downstream pressure, turn the Pilot adjusting screw anti-clockwise.
5.3 Requirements at the place of installation
- Aggressive environmental conditions may reduce the life span of the product.
- Consider the interaction between the system and the equipment. Foresee elements to absorb vibrations, pipe dilata-
tions, guides, anchoring and proper support according to the weight of the components.
- The system and operation protocol should be conceived in such a way to avoid cavitation and high velocities (as refe-
rence, max. 4 m/s or lower in case of abrasive media). Prevent pulsing fl ow or water hammers, which are very harmful
for valves and the rest of the components.
- Flooding of the product is not recommended.
- Allow enough space for valve installation, operation and maintenance.
- It is recommended to install a proper sized mesh strainer upstream the valve in order to protect seating surfaces from
abrasion or erosion that could lead to seat leakage.
-The installation of a bypass can be of help when a continuous service is needed during maintenance.
- Planners / construction companies or the owner are responsible for positioning and installing products.
6. – COMMISSIONING
Page 5
ATTENTION!
- Before commissioning the valve, check the material, pressure, temperature, fl ow direction and other essential pa-
rameters. Always use the product within the scope of intended service and operating duties.
- Before commissioning, make sure above chapters have been throughly followed.
- It is essential to fl ush the pipe system thoroughly to eliminate all the particles and impurities which could remain in
the pipes and particularly welding residue, chips, tool remains, etc. that could damage the equipment during start-
up. Ensure that during cleaning of the pipe system, any chemicals used and temperature are compatible with the
valve construction.
- Regional safety instructions should be adhered to.
- Temperatures above 50ºC or below 0ºC may cause personnel injuries if valves are touched. Ensure that the corres-
ponding warning signs are displayed on the valve or surrounding area, or isolate the equipment in case of danger.
- Before commissioning a new plant or restarting it after repairs or modifi cation, always ensure that:
- All work has been completed correctly!
- The valve is in the correct position for its function.
- Safety devices have been attached!
ATTENTION!
-
In case of valve seat leakage, the downstream pressure could not be kept in static conditions, so it is important to
foresee a safety device to relieve excess of pressure downstream the valve.
Also under dynamic conditions, in case of bad adjustment, Pilot failure or leakage through Pilot circuit, downstream
pressure could increase above the desired value, so again it is recommended to foresee a safety device to protect
downstream line against overpressure.
