2
9
2.6
2.7
Fig. 11
Fig. 12
Bladder type dampener
• The liquid is separed from the relieving chamber by a diaphragm.
• Dampener volume: about 8 times the pump swept volume.
Advantages:
• Small volume.
•
No need for periodic inflation because the gas is contained in the bladder.
Disadvantages:
• It is necessary to know prior the exact working pressure in order to
determine the damper precharge.
Dampener types
Bottle dampener
•
Is made up of a cylindrical-shape barrel developed in its height.
• Dampener volume: about 35 times the pump swept volume
.
Advantages:
• It does not need precharge because is self-running.
Disadvantages:
• It has to be regenerated periodically by releasing the liquid
through the drain valve in order to restore the air absorbed by
the liquid.
DAMPENER
DRAIN VALVE
DAMPENER
DRAIN VALVE
SPRAY
NOZZLE
PRESSURE GAUGE
(ABSOLUTELY
NECESSARY)
BACKPRESSURE
VALVE
DAMPENER
DRAIN VALVE
DAMPENER
DRAIN VALVE
Flow rate diaphragm
(with dampener)
Installation with working
pressure lower 1 bar
Spray nozzle
installation
Flow rate diaphragm
(without dampener)
Installation with working
pressure higher than 1 bar
Discharge line too long
and winding
• The pulsation dampener is decisive for a proper operation of the metering pumps.
The installation of a pulsation dampener offers several advantages because this device:
- Protetects the metering pump against pressure peaks, thus increasing the working of life of the pump.
- Prevents vibrations all along the discharge line.
- Smooth the flow, useful for the process.
• The pulsating flow, which is a negative characteristic of all metering pumps, can therefore be prevented by installing a pulsation
dampener on the discharge line (fig. 12).
Examples of installation of the pulsation dampener
INSTALLATION OF THE PULSATION DAMPENER
CAUTION ! Mechanical diaphragm metering pumps absolutely need the
installation of a relief valve; a pressure higher than the rating plate value would
break the mechanism.
• The safety valve has to be installed immediately after the discharge connection, anyhow
before the on-off valve.
• The relief valve setting (set pressure) must not exceed the pump max. pressure value.
• The safety valve protects the pump from:
Excessive pr
essure (pressure higher than the rated value).
Operator mistakes (E.G., on-off valve closed on the discharge line when the pump is running).
Obstruction of the dischar
ge piping (reduction in section clogging).
• A relief valve is absolutely necessary when an on-off valve is fitted on the discharge line (fig.11).
The installation of a safety valve is always essential both because of the above reasons and for the safety regulation for accident at work.
SAFETY VALVE
ON OFF VALVE
SAFETY VALVE
INSTALLATION
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