Applications
Food & Drink Processing Industry
Hansford Sensors Ltd has a wealth of experience in the design and manufacturing of industrial vibration sensors for various applications and can offer technical advice on specific applications. For further advice please consult our technical team on +44 (0) 845 680 1957 or email sales@hansfordsensors.com.
The food and drink processing industry uses a broad range of equipment in its manufacturing process including mixers, centrifuges, pumps, motors, air compressors, ovens, fans and conveyors.
A wide range of speeds can be present, but in the main a standard 100mV/g AC sensor (HS-100 Series) or 4-20mA accelerometer set at 25mm/sec (HS-420 Series) will provide the correct parameters for monitoring equipment. Typically the 100mV/g AC sensors will be used on-line in conjunction with a monitoring system to monitor main bearings, often used as an indication of the health of the machinery, to give continuous protection and to provide data for full frequency analysis. They can also be used off-line, with the vibration signals being hard wired back to switch/connection boxes in safe areas where data readings can be taken at intervals with a portable data collector at regular intervals for in-depth analysis. On equipment where it is judged only necessary to monitor changes in the level of vibration data over a period of time, for example misalignment, the 4-20mA (HS-420 Series) can provide a more cost-effective solution as they can be readily interfaced with a PLC (programmable logic controller), SCADA (supervisory control and data acquisition), BMS (building management system) and similar 4-20mA input modules.
For low speed applications, for example conveyors in bottling plants or canning factories, AC sensors (HS-100 Series) with a higher sensitivity (500mV/g) are suitable to improve the quality of the signal, with the further option of our HS-100F Series available in instances where an improved low frequency response is also a requirement.
For the majority of equipment Hansford Sensors recommended the standard sensitivity 100mV/g AC sensors (HS-100 Series) which are available in either top or side entry, and also intrinsically safe versions are available. Typical use of these types of sensors will be to monitor bearings on a variety of equipment. These will be hardwired back to a safe area away from machine guarding to an IP66 Switch or Connection Enclosure (HS-SE/CE Series) where vibration data can be collected.
Due largely to hygiene standards many food and drink process industries are clean environments and in controlled, clean environments stainless steel switch enclosures (HS-SE Series) are often specified by the customer when using sensors. The 4-20mA (HS-420 Series) approach described earlier is particularly suited to continuous production line systems which for example in the canning industry cover such key elements as washing, drying, cutting, mixing, canning, sealing, labelling and packaging processes. Where large areas of the plant are inaccessible or where installation costs would be prohibitive a wireless system could be used to gather the data from various accessible points and transmit to a central control room where alarms will be triggered in the event of pre-set levels being exceeded and data can be analysed in more detail.
Processes may involve some chemicals or dust (for example in the manufacture of flour and sugar) in the atmosphere in which case intrinsically safe sensors should be considered. The Hansford Sensors Intrinsically safe range of sensors are categorised for use in Dust Group II environments which meet this criteria. A further consideration is whether waterproof sensors are required. These may be required if there are regular machine wash-downs, and if chemicals are used in this process it is important to chooses a suitable cable. Temperature may also need to be taken into account where there are ovens or refrigeration areas.
Health & Safety, and even insurance requirements can dictate how and which machines are to be monitored. For example, large centrifuges used in the refinement of sugar, have to be fitted with a monitoring system, which will shut down the machine within a very short space of time when the pre-set alarm conditions are exceeded to satisfy Health and & Safety directives. Similarly where large fans are used in drying or cooling processes there are many applications where a build-up of debris on the impeller can cause imbalance. When it reaches a certain level, small lumps may fly off causing additional imbalances in the motor shafts and greater vibration. If left unchecked there is a danger the impellers may break off and cause damage. A popular way to tackle this issue is to install 4-20mA sensors (HS-420 Series) either interfaced directly to an existing PLC or similar system where alarms can be pre-set to shut the machinery down immediately if the ‘safe’ vibration levels are exceeded. Alternatively a stand-alone protection system can be installed using 4-20mA sensors (HS-420 Series) in conjunction with the Hansford Sensors vibration module (HS-510 Series). One module is required for each sensor output and each module provides two pre-programmable trip alarms and a local display. The modules are din rail mounted, or can be housed in a bespoke industrial enclosure (HS-580 Series). The vibration modules also provide the opportunity to re-transmit the outputs to a PLC or similar system.
