Microprocessor Controlled Dosing Pump

The AT3-MT is a smart dosing pump which offers batched dosing, ppm dosing, timer controlled dosing and proportional dosing to a pulsed input or 4-20mA input signal. All options can be selected from simple menu driven software.

AT3-MT Microprocessor Controlled Dosing Pump Introduction

The AT3-MT is a microprocessor controlled solenoid dosing pump.  The microprocessor control allows the dosing pump to be fully configured by the operator to provide a number of dosing modes, combined with precision delivery and chemically resistant wetted parts.

The dosing modes offered by the AT3-MT are as follows:-

• Constant flow rate - where the chemical delivery is set manually using the front mounted dial
• Proportional to a pulsed input signal - this can come from a water meter or compatible instrument, such as our P7685, P7687 or P6587
• Proportional to a 4-20mA output - supplied from a compatible instrument or process controller
• PPM Dosing Mode - the dosing pump will maintain a desired PPM rate in a pipe proportional to flow rate
• Batch Dosing Mode - the user sets volume of chemical in the pump which is then transferred or batched into a process
• Timer Dosing Mode - the user sets the volume of chemical to be transferred and sets a delay or interval timer between the batches

When operating in proportional mode the external control signal automatically varies the frequency or number of strokes the dosing pump makes per minute.  This allows the pump to increase or decrease the flow rate, depending upon the instruction from the instrument and is ideal for flow proportional dosing or pH correction applications.

The AT3-MT also includes a number of inputs allowing the pump to start / stop or pause based on set conditions.

The start / stop input from a volt free contact, is designed to operate as a low level cut-off.  The volt free input can be connected to an optional Low Level Float Switch or suction lance assembly to prevent the pump from running when a low chemical level is present.  The low level cut-off can be used in all operation modes.

The remote control input (start / stop or pause). This can be used to remotely pause the pump in all operating modes, or to initiate the Timer or Batch dosing modes.

The Flow Sensor Input works with an optional input.  When this mode is activated, the dosing pump counts the number of strokes it has made and compares it to the signal from the flow sensor.  The pump then compares the two signals and if the pump is stroking and no signal is received from the flow sensor it enters into an alarm condition.  The relationship between flow sensor outputs and pump strokes is fully user configurable (default value is 6).

The Alarm Relay is an internal alarm which energises when the pump enters an alarm condition such as a low chemical level, or no signal from a flow sensor. This can be used to either trigger remote equipment such as an audible alarm, flashing beacon, BMS or PLC system.  The volt free alarm relay can also be wired into another AT3-MT dosing pump to automatically stop / start the pumps, if they are being used in tandem.

The AT3-MT can be attached to a flat vertical surface for surface mounting installation or used with the optional foot-mounting bracket for foot mounting applications.  Designed primarily for water treatment, wastewater treatment, effluent treatment and process control, the AT3-MT is a powerful and reliable smart dosing pump dosing applications with pressure or flow requirements.

The AT3-MT is powered from a switch mode power supply suitable for a mains supply of 100 - 240 V AC 50hz or 60Hz and is designed to IP65 specification.

AT3-MT Dosing Pump Outputs

The AT3-MT dosing pump series are available with the following outputs:-

AT3-MT - Manual Control

The AT3-MT has a number of operating modes, each of which is simple to setup and integrate into a process.  The AT3-MT can be used in manual operation mode, although our AT3-BX or AT3-BL models maybe more appropriate, using the menu driven software.  The output of the pump can then be controlled using the front mounted potentiometer across 0 - 100% of the rated output.

AT3-MT Proportional to Pulsed Input / Flow Proportional Dosing

The AT3-MT series is designed to offer fair flow rates even at higher pressure and also to dose proportional to a pulsed input signal.  This volt free input signal can be supplied from a water meter or a process controller which provides a pulsed output.

When dosing proportional to the flow from a water meter, the water meter provides pulses based on the measured flow rate, eg. 1 pulse per litre.  As the flow rate increases or decreases, the number of pulses which are transmitted to the dosing pump increase or decrease, causing the dosing rate to increase or decrease. This allows the dosing pump to maintain an even delivery of chemical into the flow which is ideal for water treatment and boiler dosing applications.

When dosing proportional to a process controller, the instrument will supply a pulsed output to the dosing pump. This causes the pump speed or number of strokes per minute to increase or decrease proportionally.  The benefit of this is that the chemical reagent is delivered more quickly, the further away from the setpoint and a smaller amount as it approaches the setpoint, so reducing chemical usage and minimising the risk of over-dosing.

To ensure compatibility with a wide range of external equipment, the AT3-MT can multiply or divide the incoming pulses. The following multiplication and division modes are available:-

• 1:1 mode - where 1 pulse from the control equipment results in 1 stroke of the pump
• The signal can be multiplied from a factor of 1:n where 1 pulsed input equals n strokes, n can be any number from 1 to 999
• The signal can be divided from a factor of n:1 where n pulsed inputs equals 1 stroke, and n can be any number from 1 to 999

In 1:n dosing mode, at the first signal received, the AT3-MT will make n strokes at the maximum speed.  The AT3-MT will then measure the time between the successive pulses (maximum period of 60 seconds) and distribute the strokes evenly across the time period to ensure consistent dosing.  The time between which signals are ignored (timeout) can be set in the dosing pump software to prevent the pump from responding to signals over excessively long times.

AT3-MT Dosing Pump Proportional to a 4-20mA signal

In addition to dosing proportional to a pulsed input signal, the AT3-MT is a 4-20mA proportional dosing pump allowing the pump speed to be automatically regulated.  By default, the AT3-MT stops at 4mA and at 20mA to allow the user to set the dosing rate (eg. 100% at 20mA).  The 4-20mA input signal can be configured in the dosing pump software in the following ways:-

• Invert the 4-20mA signal (e.g. 100% at 4mA and 0% at 20mA)
• Expand the 4-20mA signal (e.g. dose at 0% at 8mA and 100% at 12mA
• Select a flow rate to dose at based on the 4-20mA signal, the figure can be entered in Percentage, frequency, L/Hr, Gph or ml / min.

AT3-MT PPM Dosing Pump

The AT3-MT is ideal as a chlorine dosing pump when dosing concentrated or diluted solutions of sodium hypochlorite as it allows a set PPM rate to be maintained in a pipeline or flow.  Using a water meter to measure the flow rate the AT3-MT delivers enough chemical reagent into the flow to maintain a set PPM rate.  The PPM rate is entered into the pump software using the menu driven configuration process.

The higher pressure flow output, even at elevated pressures, means that the AT3-MT is ideal for water treatment applications, even when large diameter or high flow transfer pumps are in use.

AT3-MT Batching Dosing Pump

The AT3-MT can also be used as a batching dosing pump with the required amount to be batched easily set using the inbuilt dosing pump software.

In batch dosing mode, the AT3-MT can be configured to deliver a set volume of chemical.  The range is from 0 - 30'000ml (30.000 litres) which can be started by pushing the enter button on the pump itself or by using a volt free signal to the remote stop / start input or from using the pulsed input from a water meter.  The amount to be batched is entered in ml (millilitres) into the pump software.

The amount of chemical that has been transferred in dosing mode is counted on the bright LCD (Liquid Crystal Display) so the operator can see both the amount to be batched, and how much has been batched so far at the same time.

When working to an external signal, when the signal is received, the dosing pump will then batch the desired amount of chemical.  The AT3-MT includes a memory function which allows it to store input pulses.  This allows multiples of the batched amount to be transferred if required.

The speed at which the chemical reagent is batched into the process can be manually adjusted, allowing the flow rate to be set between a value of 1% and 100% of the pumps rated output.

AT3-MT Timer Controlled Dosing Pump

The AT3-MT offers a sophisticated timer dosing mode, allowing the timer to be set by pushing the dosing pumps enter key, or from a remote volt free signal.  The pump can be set with a delay timer so that it begins dosing at a set time, with an interval timer between two successive doses.  The timers can be set in Days, Hours and Minutes.

AT3-MT Wetted Parts / Liquid End

The AT3-MT is designed as a chemical metering pump for industrial usage and as such has wetted parts developed specifically for chemical handling.

As standard the AT3-MT is available with a liquid end manufactured in either PVC or PVDF, with Ceramic or PTFE balls and a PTFE diaphragm.  The seals and O-rings are available in either Viton (© DuPont / Chemours) or EPDM with PTFE O-rings available as an option.

Our chemical compatibility database can be used to check the wetted parts.  Please don't hesitate to get in touch if you are unsure.

Priming the liquid end for dosing couldn't be simpler.  The AT3-MT is supplied with tubing and has an adjustable bleed valve located on the pump head.  Loosening the bleed valve allows the chemical reagent to be circulated through the pump, quickly and easily, to ensure accurate dosing.

What's in the box with the AT3-MT?

The AT3-MT is supplied complete with everything required to begin metering chemical reagents into a process.

Supplied with the dosing pump itself are:-

• Injection Valve with 3/8" and 1/2" BSP male threaded connections
• Foot-valve & Strainer assembly
• 1 metre of discharge tubing
• 2 metres of suction / bleed tubing
• Surface mounting kit

An optional foot mounting bracket can be included for no additional charge if requested.

AT3-MT Features & Benefits

The AT3-MT is a powerful, reliable and accurate chemical dosing pump, designed for general purpose dosing applications where dosing accurately to an external signal, batching a specific amount of chemical, maintaining a PPM rate, or running for a desired time period is required.

The AT3-MT is ideal for water treatment applications, even where large flow rates or large diameter pipework is used, and can be installed as either a stand alone device or as part of a larger integrated piece of control equipment.

The powerful dosing pump software makes the AT3-MT ideal for operation directly on the pump or from a remote stop / start signal from a PLC or the relay contact outputs of a process controller such as a pH controller or Conductivity controller.

When operating in proportional control modes, the AT3-MT can condition the signal to ensure that the operation of the dosing pump is as required by the process.  This includes full inversion and expansion of the 4-20mA and granular multiplication and division of the pulsed input, making setting up and commissioning the metering pump as simple as possible.

The microprocessor driven dosing pump can operate in batch dosing mode and timer dosing mode independently from external controls, ensuring simple batching processes are delivered accurately and safely.

Adding simple control devices such as a low level float switch, and flow verification input from a flow sensor allows the dosing pump to stop in an alarm condition, to ensure processes can be controlled safely.

For more complicated applications, the output alarm relay can be used in a number of ways, including connecting to another AT3-MT, an external audible / visual alarm, or integrated into control panels, PLC's, BMS systems or other devices.

For more sophisticated applications, the AT3-MT can use the remote Start / Stop / Pause functionality to call for batching or timer based dosing of chemical reagents, as well as 4-20mA operations with conditioning of the signal taking place in the dosing pump software.  This ensures that the AT3-MT can be ready for even the most demanding dosing application.

Each of the different dosing modes of the AT3-MT are simply selected using the menu driven programming guide.  The onscreen prompts and simple push button operation means that programming the AT3-MT is as simple as possible.

The AT3-MT is designed specifically for chemical dosing with the wetted parts suitable for many chemical reagents, with a liquid end manufactured in PVC or PVDF, a PTFE diaphragm, Ceramic or PTFE balls and either Viton, EPDM or PTFE seals and O-rings.  Designed to IP65 specification, the AT3-MT is suitable for mounting outside.

The AT3-MT is available as the following model types:-

• AT3-MT-16-07 for an output flow rate of 7.0 Litres / Hour at 16 Bar pressure
• AT3-MT-10-10 for an output flow rate of 10.0 Litres / Hour at 10 Bar pressure
• AT3-MT-14-08 for an output flow rate of 14.0 Litres / Hour at 8 Bar pressure
• AT3-MT-18-02 for an output flow rate of 18.0 Litres / Hour at 2 Bar pressure

The AT3-MT is designed to IP65 specification, making it suitable for locating either inside or outside and is powered from a switch mode power supply. The instrument is able to accept a mains supply of 100 - 240 VAC at 50Hz / 60Hz making the AT3-MT suitable for export markets too.

As part of our Red Dosing Pump range, the AT3-MT is rated hot for continuous dosing duty, and the pump is designed to provide a long trouble free life of accurate chemical dosing.