pH Instruments and pH Electrodes pH Meters Portable pH meters are those instruments which can be taken out on to the plant or into the field and used to accurately measure the pH of a wide range of solutions from process vessels to swimming pool water, lakes or rivers. Automated Water & Effluent Ltd (AWE Direct) currently offer two styles of portable pH instrument the increasingly popular stick type and the traditional hand held type with a separate electrode attached to the instrument with a cable. pH Transmitter The pH Transmitter is an instrument for mounting within approximately 3 metres (10’) of the pH electrode system. The best pH transmitters have a display and calibration controls for zero and span so the system maybe calibrated or buffered local to the electrode. The current output is an industry standard 4 – 20 mA output with the same two wires which power the 24 VDC transmitter carrying the current output. pH Controllers pH Controllers are pH instruments which have the ability to operate a remote device. The output can either by a relay which switches at a pre-set pH value or an analogue control signal. The analogue control signal must not be confused with a recorder output, which is a linear output corresponding to the measuring range of the instrument and should not be used for control. pH Electrodes A good quality pH electrode is the secret to any pH measurement application. Automated Water & Effluent Ltd (AWE Direct) carry a very wide glass bodied pH electrode range. Our range of high quality pH electrodes are used in a number of applications including swimming pools, laboratories, process control, water & effluent treatment. A glass bodied pH electrode can aslo be paired with one of our inline electrode holders; where the electrode holder becomes part of the pipework. For our PVDF or PVC bodied pH electrodes designed to be directly screwed into pipework please see our pH probe section. pH Probes Our pH probe range give precision measurements in industrial environments. The pH probes are manufactured in either PVDF (Kynar) or PVC, with a number of reference options including annular ceramic, porous Teflon or PTFE junctions. All of our pH probe range are tapped (threaded) for screwing directly into a process. pH probes can be tapped on the measurement side for screwing directly into pipework for inline measurement or tapped on the reverse side for screwing into pipework for submersion. Within the range we have pH probes that are tapped on both sides allowing the same probe to be used for inline or submersion use. For glass bodied pH probes or use in electrode holders or laboratory style applications please see our pH electrode section. Inline pH electrode systems When the pH needs to be constantly monitoring inside a pipe or pipework our inline pH electrode holders are the perfect solution. We have different models for larger and smaller diameter pipework each compatible with our standard pH electrodes and pH probes. Each features a simple quick release mechanism for removing the pH probe or electrode for maintenance or calibration. In addition - we have retractable inline pH electrode systems for the easy removal of pH electrodes in pressurised vessels without having to halt the process being measured. pH Simulator The APS2 pH & mV simulator is a source of precise mV signals for calibrating pH and mV meters. It is substituted for the service electrode and maybe also be used to check the serviceability of extension cables and of wiring within the meters themselves. pH Buffer Solutions pH Buffers calibrating a pH electrode and instrument is often referred to as buffering the system. The electrode is removed cleaned and immersed in a solution of a know pH value and the instrument is set to read this value. This is usually carried out for 2 values so the zero and span can be accurately set. Automated water & Effluent Ltd (AWE Direct) offer buffers in values of 4.00, 7.00, 9.00 and 10.00 pH either as liquid or powder to mix your own buffer solution.