Automated Water & Effluent Ltd



AWE Ltd Watermark

New Universal Instrument, pH Correction Skids, Sodium Hypochlorite dosing pumps and more in the AWE Summer 2016 Watermark

Universal Instrument

pH correction skid.

The CMC-99 is a new panel mounting 96 DIN format universal instrument with a 320 x 240 pixel and 16 Bit colour, TFT touch screen display.

The CMC-99 is designed to work with external sensors or transmitters which provide the signal inputs to a number of channels.

The precise number of channels depends upon the input modules fitted at manufacture.

The basic input model offers 3 universal inputs, which may be 4-20mA current signals from either 2 wire transmitters with 24 VDC loop power supplied, or from instruments with a powered 4-20mA current output.

Examples are our P3630 two-wire pH transmitter and C3630 two wire conductivity transmitter.

Powered instruments could include our P7635 pH controller for pH measurement or for conductivity the C7635 Conductivity Controller.

The universal inputs also include temperature inputs from either RTD Pt100 sensors or a wide range of thermocouples for higher temperature use.

For a greater number of inputs the CMC-99 is available with 6 x 4-20mA current inputs is available, plus many other options, including:-

  • 4 x RTD Inputs
  • 8 x Thermocouple inputs
  • 4 x Flow inputs

The TFT touch screen may be user configured to display data in groups if a large number of inputs are employed.

Options of displaying the data include:- Analogue meter movement displays.
Bar graphs (which work well with tank level displays)
or simple numerical displays.

The screen is also able to display graphical information as an electronic chart recorder with the display either going horizontally or vertically with white or black backgrounds.

The data may be logged to the 1.5Gb internal memory and downloaded by basic connection interfaces (USB and RS485).

Being a truly universal instrument we are also able to offer control output modules which include 8 x SPST relays for on / off control rated at 1amp, or 4 x SPST relays rated at 5amp, and either 2 x 4-20mA outputs, or 4 x 4-20mA output, with an option for PID control.

Mains supply is by a switch mode power supply which accepts a supply voltage of 86 - 264 VAC at 50 / 60Hz. This is ideal for both the domestic and export markets with the option of a low voltage AC or DC power supplies being requested when ordering.

Sodium Hypochlorite Dosing

PVDF head for dosing sodium hypochlorite

In the Winter Watermark 2011 we wrote about the merits of the automatic degassing head, which at the time was manufactured from solid PVC bar.

We are pleased to reintroduce the degassing head moulded in PVDF; which offers greater chemical resistance to the chemical reagents being dosed.

Dosing chemicals with a low vapour pressure - which include sodium hypochlorite and hydrogen peroxide - is always difficult especially when installed with a suction lift from a chemical drum or dosing tank.

Where space is allowing, the best solution is to install the pumps on a flooded suction so that the chemical reagent flows by gravity into the pump head.

We manufacture an all polypropylene and PVC kit for this purpose, where the dosing tank is raised off the ground, and the dosing pump mounted at low level so the chemical enters the pump gravity.

There can be problems when sucking the chemical reagent from the drum up to the dosing pump. The low vapour pressure means that the gas is drawn out of the liquid in the suction tubing causing air (gas) locks in the dosing tube.

By using the degassing head, liquid is taken from the head at a lower level and the vapour at a higher level. The vapour is returned to the chemical drum below the liquid level so it can re-dissolve into the chemical.

Please note - when using any degassing head, the pump output is reduced to 80% of the pumps rated output due to the liquid being taken off at a lower level in the pump head.

Flooded Suction Kit

Stainless steel Mechanical Dosing Pump for dosing viscous polymers installed on a flooded suction

We recommend combining the flooded suction kit with a polypropylene stand to lift the dosing tank. This allows a gravity feed of the chemical into the dosing pump.

In this installation a stainless steel piston pump is used for dosing a viscous polymer.

We are able to supply and fit to the dosing tank either a PVC or PVDF low-level float switches which can be connected directly to the dosing pump input if it is fitted with a low-level cutout.

A low level cut out is often used to prevent the pump from running dry, or operating when a low chemical level is present.

Simple pH Dosing Station

pH correction skid.

We recently helped a customer who a pH problem with the discharge of his running rinse water from his phosphating process.

The flow rate was small but could go above or below his pH consent to discharge limits with the local water authority.

As the existing pH adjustment tank was outside, the equipment needed to be mounted close by. So we supplied one of our double confinement dosing stations to hold the acid and alkali reagents and their dosing pumps. Also mounted inside the dosing station was our MO5-pH surface mounting pH controller.

This was supplied mounted and ready wired for easy site installation. Mounted on the side of the polypropylene housing was the starter for his neutralising mixer.




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AWE Summer 2016 Watermark

The 2016 Summer Watermark is available as a PDF for printing or to read offline.

If you would like to receive email reminders when the winter watermark is published then please fill in your contact details on the Past Newsletters Page or at the bottom of this page.

If you require any more information regarding our universal instrument or advice on dosing chemical with a low vapour pressure like Sodium Hypochlorite then please don't hesitate to get touch.

We offer a number of engineered solutions including our backplate systems, dosing skids and cabinets.

Whether it's water treatment, process control or effluent treatment, our engineering team have the experience and the expertise to advise on our engineered solutions to assist with your requirements.

For more information on our systems or to discuss a specific system please don't hesitate to get in touch on 01785 254 597 or by emailing sales@awe-ltd.co.uk and we will be happy to discuss your application.

Contact AWE Ltd sales on 01785 254 597 for more information or to purchase our products.