Pump Solutions Group Neptune Solenoid-driven Diaphragm Metering Pump ARPZ-31_61_12 - Manual (Page 54)

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Spare parts & options
■Spare parts
• Nuts • Retaining rings • Joints • Air-release nozzles
■Options
• Back pressure valve
This valve prevents overfeeding* 1 and siphoning* 2 phenomena by sealing the chemical outlet with a diaphragm and
applying just the right amount of pressure (back pressure) to suppress the in-ertia force of the fluid.
• Relief valve
This valve automatically releases abnormal pressure that occurs in the discharge-side piping, due to blockage by for-
eign objects and tightening of the valve, to prevent accidents or possible damage to the pump and piping.
• Air chamber
Reciprocating pumps may develop pulsation, which causes pipe vibration and overfeed. If this is the case, use of an
air chamber can regulate the chemical into a more continuous flow and alleviate the various problems associated with
pulsation. When an air chamber is to be installed, be absolutely sure to provide the relief valve mentioned above.
• Accumulator
The accumulator is provided to reduce pulsation, and the principle behind its operation is the same as that of the air
chamber. It is effective at high pressure levels above 0.5 MPa and when using liquids that are affected by air.
• Level Switch
This sensor detects the low chemical level in the tank. Two models, a 1-point (single-sensor) and a 2-point (double-
sensor) model, are available.
• Flow checker
This highly acid- and alkali-resistant, low-cost flow meter allows you to monitor injection operation of the pump. It can
be directly attached on the discharge side of the pump.
• Flow indicator
The discharge operation can be monitored at a glance by attaching this indicator at the discharge side of the pump. It
also helps to prevent injection trouble.
• Deforming joint
Installed on the suction side of the pump, this joint separates air bubbles and fluid to prevent air bubbles from entering
the pump head.
• PTU-25/50/100
These are chemical injection units consisting of a metering pump and PE tank (with a capacity of 25, 50 or 100 liters).
• Chemical tank
Tanks made of PE (with a capacity ranging from 25 to 100 liters) or of PVC (with a capacity ranging from 100 to 1,000
liters)
• Solution tank
These tanks (made of PE with a capacity ranging from 50 to 500 liters) can have a metering pump or agitator mount-
ed on top.
• Parts kit
This kit contains a complete set of all required consumables.It is economical, and an easy way to store and man-
agethe parts you need.
Explanation of terms
• Overfeed
The phenomenon that the force (inertia) of the discharge during chemical flow with pulsation causes chemicals to
continue flowing when chemical flow should stop, resulting in excessive chemical discharge beyond the specified vol-
ume.
• Siphoning
The phenomenon that chemicals continue to be sucked out naturally and continue flowing when the tip of the pump's
discharge-side piping is lower than the level of liquid in the suction-side tank.
• Cavitation
This phenomenon that the negative pressure inside the pump head causes air bubbles to form, diminishing the dis-
charge volume and causing abnormal noises and vibration.
✽ For more detailed information, ask for “How to use metering pumps properly,” a technical document provided by
TACMINA.
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