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1.0 INTRODUCTION
1.1
Safety and Caution Notes
Always wear protective clothing, eye protection and gloves before working on or near a
metering pump. Follow all recommendations of the supplier of the solution being
pumped. Refer to the MSDS from the solution supplier for additional precautions.
Walchem EH and EZ Series metering pumps should be installed where ambient
temperatures do not exceed 122°F (50°C) or do not fall below 32°F (0°C), or where
pump or tubing are directly exposed to sunlight.
WARNING Risk of electrical shock!
This pump is supplied with a grounding
conductor and grounding-type attachment plug. To reduce the risk of electrical shock,
be certain that it is connected only to a properly grounded, grounding type receptacle
with ratings conforming to the data on the pump data plate. Prior to performing any
maintenance on a pump, disconnect the pump from the electrical power source.
Plumbing Precautions
All tubing must be securely attached to the fittings prior to starting the pump (see
Section 2.3). Only use Walchem tubing with your pump. Tubing should be shielded to
prevent possible injury in case of rupture or damage. UV resistant tubing should be
used if the tubing is exposed to UV light. Always adhere to local plumbing codes and
requirements. Be sure that the installation does not constitute a cross connection.
Walchem is not responsible for improper installations. Prior to performing any
maintenance on a pump, depressurize the discharge tubing.
If you are pumping downhill or into little or no system pressure, a back pressure/anti-
syphon device must be installed to prevent over-pumping. Contact your Walchem
distributor for additional information.
Solution Compatibility
CAUTION!
This pump has been evaluated for use with water only. The suitability of
this pump for use with liquids other than water (such as acid and alkaline) is the
responsibility of the user. For liquids other than water, select the best-suited liquid end
material combination using a chemical compatibility chart.
1.2
Principle of Operation
The EH and EZ series electronic metering pumps consist of a pump unit, a drive unit,
and a control unit. The drive unit is an electromagnetic solenoid. When the solenoid
coil is energized by the control unit the armature shaft moves forward due to the
magnetic force of the solenoid. The shaft is attached to a PTFE faced diaphragm which
is part of the pump unit. The diaphragm is forced into the pump head cavity decreasing
volume and increasing pressure which forces liquid in the pump head out through the
discharge check valves. When the solenoid coil is de-energized, a spring returns the
armature to its starting position. This action pulls the diaphragm out of the head cavity
increasing volume and decreasing pressure.
Atmospheric pressure then pushes liquid
from the supply tank through the suction check valves to refill the pump head.
Содержание EH Series
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