Sensys Ltd

+44(0)1438 759595

EHE series metering pump

The Iwaki EHE series is a large output capacity (up to 75 l/ hr), weatherproof, full microprocessor control analog/ digital metering pump. High resolution chemical delivery via stroke length which can be set between 20-100% and stroke rate between 0-360 spm. Combining the EHE performance and a turn-down ratio of 1800:1 yields one of the most versatile pumps on the market today. The controller includes a microcomputer that enables a single pump to operate in four modes (manual/ proportional control/ pulse control/ count control). The pump body, aluminium die-cast frame is moulded by reinforced plastics (GFRPP), has a weather and dust-proof structure that is immune to liquids and atmospheric corrosion (IP65).

1. Manual mode
Stroke rate can be increased or decreased by 1 spm anywhere within the range 0 to 360 spm and can be changed either before or during operation.
2. Proportional control mode
The stroke rate can be proportionally controlled based on external DC 0-20mA signals. Select an input signal by means of the keys.
3. Pulse control mode
The EHE pump performs division control operations in response to external pulse signals. The pump provides one shot per (n) times pulse inputs. Set the number (n) between 1 and 999 by means of the keys.
Pulse-control

4. Count-control mode
The EHE pump performs count-control operations in response to external pulse signals. The pump provides (n) times shots per pulse input. Set the number (n) between 1 and 999 by means of the keys. If the next pulse is received before a set number of shots have been completed, the pump is capable of storing that pulse signal (max. 255 pulses). The pump can be programmed to store the pulse input or not.
count-control

Standard control features
• on-off
• pulse signal, (e.g. can be controlled by water meter) with additional pulse/ count control, (divide or multiply pulse numbers) for finer
• control
• digital input (e.g. stop switch)
• analog input (proportional) external 4-20 mA signal

Summary of features and benefits
• VC version with ceramic valve balls
• VH version with Alumina C276 valve balls, (for caustic)
• very powerful electronic metering pump with high dosing capacities up to 75 l/ hr
• weatherproof (IP65)
• self primes in seconds
• single level stop function
• manual vent valve (helps priming)
• high speed operation, up to 360 strokes per minute results in high resolution chemical feed and elimination of slug-feed effects
• manually adjustable stroke rate and length for finer control
• two digital external input modes and four analog external modes
• superior valve construction, with double ball check valves. Ball, seat & guide assembly ensures a tight seal to prevent loss of prime
• supplied with tubing, check valve and foot valve
• long lasting diaphragm. PTFE laminate over EPDM is moulded onto a solid core. A retainer plate is provided to minimise flow rate
• changes as pressure varies

The PosiFlow sensor will verify that
your metering pump is truly moving
liquid and has not lost prime.

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Product enquiry

Pump terminology
• on-off control
Pump is driven by externally powered device, e.g. Walchem controller.
• timer control
Pump is switched on/off on a daily, weekly or bi-weekly timer program.
• pulse signal control
Dosing can be controlled via signal pulses from a water meter. One shot of chemical per pulse only, e.g. EWN-R pump.
• pulse control/ count control
Pump can divide or multiply pulses from a water meter to decrease or increase shots of chemical per pulse, e.g. EWN-R & EHE.
• analog input control
Proportional control via a 4-20 mA signal.
• digital input control
Pump can be controlled by a digital stop/ start signal, for example a level switch or interlock.

Lost prime?
Typically, the pump will sound much louder than when pumping normally against pressure. Looking at the discharge point of the pump or tubing is a 100% sure way to check for pumping. Non-moving pockets of air in the suction or discharge line is another good way to tell whether or not there is chemical moving. The easiest way, solving most of the problems at the same time, is to open up the Manual Air Vent Valve and check that the pump is pumping out the air vent

How do I prime the pump?
Open up the Manual Air Vent Valve, (make sure it is plumbed with tubing back to the supply tank) and operating the pump until all the air is purged from the suction line and within the pump head. Once it is primed, close the MAVV and resume operation. If it loses prime again, the pump head should be disassembled and inspected for bad seals, gaskets trapped under o-rings, debris obstructing a seal, etc. Reassemble with new parts from a parts kit and reprime.

Can I use any tubing with Iwaki pumps?
Tubing is an integral part of the pumping system and the connections between tubing and fittings is critical. Sensys recommends using Iwaki supplied tubing, however other tubing can also be used. Caution has to be used when using other tubing as tolerances and pressure ratings can vary.

Are there repair kits available?
Parts kits are available for every liquid end option and are basically comprised of the elastomeric parts including the diaphragm and valve guide assemblies.Complete head assemblies can also be ordered as spares. These can be used to change over the liquid end to change materials of construction or to replace damaged parts.

Top tip for AAV installation
Place a single loop on the air bleed return line to prevent crystallisation of dosing chemical blocking the gas outlet.

Iwaki pump with AAV loop