Automatic Sensor Cleaning System
Process Instruments were approached in 2008 by a customer who was having to change their pH sensor every week at massive cost due to the fouling of the sensor. In response Pi developed the AutoFlush.
The idea for the AutoFlush is simple and effective. After a user defined time period, the sample drains away and the sensor and sensor housing is flushed with clean water. This water flushes the whole of the inside of the sensor housing taking away any build-up of solids to the drain. The repeated flushing of the housing and sensor helps prevent the build-up of solids and so prolongs the life of the sensor and reduces maintenance.
- Flushing prevents the build-up of solids
- Reduced maintenance
- Suitable for pH/ORP/Cl2/O3/ClO2
- User-selectable flush duration
- User-selectable flush frequency
- ‘Flush now’ facility
- Simple, infrequent maintenance
Water quality sensors often become fouled by dirt, causing erroneous results. The quality of the sample affects how severely the sensor become fouled and how often they need to be cleaned and/or replaced.
Cleaning sensors can often be time-consuming and unnecessarily costly. Automatic cleaning systems from Pi solve this problem.
The AutoFlush by Process Instruments extends the life of sensors and drastically reduces maintenance procedures, and therefore cost, by automatically cleaning the installed sensors at intervals chosen by the user.
The Pi analyser, which is linked to the AutoFlush, allows users to set up probe cleaning intervals specific to their application, which removes the need for manual sensor cleaning.
During the cleaning cycle, the readings of the probe(s) can be held so that erroneous data is not recorded on the analyser.
Using the CRIUS®4.0 or CRONOS®, the AutoFlush can be customised depending on the application. Users can adjust the time it takes for the cleaning cycle to become active and the duration of the clean.
The AutoFlush has been installed around the world in paper mills, food factories and other plants where keeping the sensors clean enhances their performance.
There are three types of AutoFlush cells, for different applications;
- AutoFlush (Clean) Flow Cell – particulate and fibre-free process water which is at a constant low pressure.
- AutoFlush (Fibre) Flow Cell – process water containing particulates and/or fibres which is at a constant low pressure.
- AutoFlush (Process) Flow Cell – process water containing particulates and/or fibres which is at a constant low pressure at intermittent processes where a process run/stop signal is provided. During a process stop, the sensors are cleaned and stored wetted in flush water until the process is started again.
The AutoFlush is designed to allow up to two sensors to be installed. It can be used with Pi’s pH, ORP, free chlorine, total chlorine, ozone, chlorine dioxide, peracetic acid and hydrogen peroxide sensors (or a combination of sensors).
We also offer cleaning systems for our other probes, such as the SoliSense®, TurbSense®, OxySense and UV254.
- Flushing prevents build-up of solids
- Reduced maintenance
- Suitable for pH/ORP/Cl2/O3/ClO2
- User selectable flush duration
- User selectable flush frequency
- ‘Flush now’ facility
- Simple, infrequent maintenance
The AutoFlush cell requires zero maintenance, other than the obligatory sensor maintenance (consumables). The AutoFlush cell is cleaned whilst the cleaning cycle is active.
After a user-defined period, the open to atmosphere sample drains away and the sensor and sensor housing is flushed with clean water. This water flushes the whole of the inside of the sensor housing taking away any build-up of solids to the drain. The repeated flushing of the housing and sensor helps prevent the build-up of solids and so prolongs the life of the sensor and reduces maintenance. For waxy or fatty build-ups, warm water can be used to flush the sensors.
The signal from the sensor is held and the whole flow cell including the sensor(s) is flushed with clean water. For customers, this means a new pH sensor after 18 months rather than sooner, resulting in a significant improvement in process control and a very significant saving in pH sensors.
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Sensor Fouling
Whatever the process being monitored, there is often something in the sample water capable of fouling a sensor, and therefore causing erroneous results. The obvious solution to this problem is to clean the sensor, but how frequent should inspection and cleaning programs be for each piece of instrumentation? Too frequent and the inspection and cleaning regimen is time consuming and unnecessarily costly. Not often enough and the instrumentation will give false results and possibly fail prematurely.What is the solution?
Process Instruments’ AutoClean and AutoFlush Systems
Simple, reliable and easy to maintain, Process Instruments’ AutoClean/AutoFlush systems are an alternative to mechanical cleaning mechanisms which can clog and break. By frequently spraying the sensor/probe with clean water or air, the sensor remains clean and free from fouling for extended periods of time. The sensor cleaning cycle is activated by Pi’s controller for a user selectable length of time and frequency so that no matter how dirty the application, the probe remains clean. With no moving parts in the sensor body or in the cleaning attachment there is nothing to replace or check other than a simple valve positioned in an easy to reach location. Pi’s AutoClean and AutoFlush systems can give trouble free and fouling free functioning of sensors for weeks, if not months, at a time.A solution for each application
AutoClean
This option can be added to our pH, ORP, Turbidity, Suspended Solids and Dissolved Oxygen (DO) sensors. Consisting of an end cap to direct the flow of clean water (or air for a DO sensor) across the face of the sensor blasting any dirt away. The cleaning is controlled by a single valve positioned in an easily accessible location.AutoVerify
If using air to clean a DO sensor the system can also automatically verify that the sensor is still responding correctly, removing any need to remove the sensor from the sample for months at a time.AutoFlush
For sensors that require flow cell mounting like Chlorine, Ozone and Chlorine Dioxide, an Autoflush system has inbuilt valves which automatically start/stop the sample flow and control the flow of clean water past the probe. The user can set the flushing interval and duration to keep the flow cell and sensor clear from fouling. For particularly dirty or stubborn contaminants, warm water can be used as the flush water to aid cleaning. With the above options, whatever the application or parameter being measured, Process Instruments will be able to provide a monitoring system that will not only be accurate, precise and long lasting but that will also remain free from fouling and save the operator both time and money.Document | Type | Size |
---|---|---|
AutoFlush | Brochure | 563kB |
Probe Fouling | Technical Note | 459kB |
AutoFlush | Technical Note | 1.6MB |
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