The Food 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 or 4-20mA sensor set at 25mm/sec will provide the correct parameters for monitoring equipment. Typically 100mV/g 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 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 e.g. misalignment the 4-20mA (HS-420 Series) can provide a more cost-effective solution as they can be readily interfaced with PLC, SCADA, BMS and similar 4-20mA input modules.
For low speed applications, e.g. conveyors in bottling plants, canning factories, our HS-100 Series with a higher sensitivity e.g. 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.
Location: For the majority of equipment our standard HS-100 top entry or HS-100S side entry, or in the case of intrinsically safe requirement HS-100I or HS-100IS Series will be suitable with a standard sensitivity of 100mV/g. 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 process industries tend to be clean environments and in these controlled, clean environments stainless steel switch enclosures are often specified by the customer (HS-SE-SS Series) when using HS-100 Series sensors. The 4-20mA 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 plant are inaccessible or where installation costs would be prohibitive there is the option of a wireless system to gather the data from various accessible points and transmit these 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 (e.g. in the manufacture of flour and sugar) in the atmosphere so intrinsically safe sensors may need to be considered. Our Intrinsically safe sensors are categorised for use in Dust Group II environments to 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 unthinkable 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 the ‘safe’ vibration levels are exceeded. Alternatively a stand-alone protection system can be installed using HS-420 Series sensors in conjunction with HS-510 modules (one module required for each senor output) which provides two pre-programmable trip alarms and a local display. The units are din rail mounted, or can be housed in a bespoke Industrial Enclosure (HS-580 Series).The HS-510 module also provides the opportunity to re-transmit the outputs to a PLC or similar system.