Bonfiglioli C/A/F/S Reducer ATEX Installation and Maintenance Practice Guide



Bonfiglioli C/A/F/S series reducers ATEX installation and maintenance practice guide

In industrial fields such as chemical, pharmaceutical, and grain processing where explosive dust or gases exist, the installation and maintenance of reducers as key power transmission equipment are directly related to the safety of the entire production facility. Bonfiglioli's C-series (parallel axis), A-series (bevel helical gear), F-series (shaft mounted), and S-series (single-stage) reducers are widely used in various heavy-duty conditions due to their modular design and strong load-bearing capacity. When these devices are designated for use in ATEX explosion-proof areas, their installation, operation, and maintenance have more stringent requirements than conventional equipment.

Security and Reception: The Foundation of Project Success

Before any installation work begins, safety is the primary consideration. The Bonfiglioli manual clearly states that as a component of the machine, the safety of the gearbox after final integration is the responsibility of the manufacturer of the entire machine. But for on-site installation personnel, the following points are crucial:

Nameplate verification: The equipment's Nameplate contains all key information, such as serial number, model, mounting position, and ATEX classification. When the serial number is 17 digits, the year is in the 3rd to 4th digits; At position 13, it is in positions 5-6. During acceptance, it is necessary to confirm that the "installation position" on the nameplate is completely consistent with the actual installation method. Any deviation, even a slight angle tilt, must be authorized in writing by Bonfiglioli's technical department before execution, otherwise ATEX certification will automatically become invalid.

Long Term Stock: If the device is not installed immediately, the manual provides detailed long-term storage guidance. For devices with the "LONG TERM STOCK" option, they are packaged in VpCI (vapor phase anti rust) bags and clearly labeled "ON before installation". The storage environment of such devices must be strictly controlled: temperature -10 ° C to+40 ° C, dry and without direct sunlight. Storage exceeding 2 years must be sent to Bonfiglioli service center for re inspection.

Packaging treatment: Standard packaging is not designed to be waterproof and is only suitable for dry warehouses with roofs. After unpacking, it is necessary to check whether the plastic protective cover during transportation has been removed, and it is forbidden to use the lifting ring bolts on the motor to lift the entire reduction motor, which will seriously change the center of gravity and cause safety accidents.

Key installation points in ATEX environment

When the gearbox is used in hazardous areas such as Zone 21 (dust) or Zone 1 (gas), a series of special regulations must be followed during the installation process to prevent potential ignition sources.

Surface temperature management: The core of ATEX certification is to control the surface temperature of equipment. The nameplate indicates the maximum surface temperature (e.g. T4 is 135 ° C). During installation, it is necessary to ensure that the on-site ambient temperature does not exceed+40 ° C (synthetic oil) or+40 ° C (mineral oil), and that the surface temperature of the gearbox does not exceed+100 ° C (housing) and+95 ° C (oil temperature) during continuous operation. The manual emphasizes that continuous operation is not recommended if the surface temperature (ts) and oil temperature (to) are within the range of 80 ° C to 95 ° C.

Dust prevention and sealing: For Zone 21/22 (dusty environment), after installation, it is necessary to:

Clean all unused threaded holes: Block all unused installation holes with the screw plugs (coated with Loctite 510 thread locking adhesive) provided with the goods to prevent dust accumulation.

Apply sealant: Apply sealant (such as Loctite 5366) on the flange joint surface and positioning joint of the motor and reducer to prevent dust from entering or accumulating through the gap.

Torque arm installation: F-series shaft mounted reducers must use the original anti vibration kit provided by the factory. It is necessary to ensure that there is no sliding friction between metal parts during operation, and non-metallic anti friction components should be installed if necessary.

Static protection: Do not connect objects with a resistance exceeding 10 ΩΩ to the reducer. Plastic components, such as fan covers, must be ensured not to accumulate static charges.

Bolt tightening torque: In ATEX environment, all external bolts (including installation bolts and oil plugs) need to be coated with Loctite 510. The tightening torque must strictly follow the manual's "Table 1" (for structural bolts, grade 8.8 or 10.9) and "Table 2" (for oil plugs, such as 1/2 "oil plug torque of 14 Nm and M14x2 torque of 30 Nm). Special warning: If the gearbox housing is made of aluminum (such as small models), it is strictly prohibited to use bolts higher than grade 8.8 for installation to avoid crushing the threads.

Core process of mechanical installation: tightening disc and hollow shaft

The F series and some A/C series use hollow output shafts with shrink discs for installation. This is the most common installation difficulty, and the following is the standardized workflow:

Cleaning and lubrication (key steps): It is absolutely forbidden to apply molybdenum disulfide or any lubricating grease on the mating surface between the tightening disc and the machine shaft, as this will significantly reduce the friction coefficient and cause the tightening disc to slip and fail. These contact surfaces must be thoroughly cleaned and degreased. On the contrary, solid lubricants with a friction coefficient of μ=0.04 (such as Kl ü ber Molybdenum UMF T4) should be used on the non mating surface of the tightening disc (i.e. the sliding surface of the tightening disc itself).

Installation steps:

Install the reducer onto the machine shaft.

Install the tightening disc and pre tighten the bolts by hand.

It is necessary to use a torque wrench to gradually tighten all bolts in a clockwise sequence in multiple times until the final torque Mt specified in Table 4 is reached. This operation usually requires repeating 2-3 cycles to ensure uniform clamping.

Axial fixation: In the presence of external axial thrust, vibration, or installation posture with the output shaft facing downwards (such as B6 or H5 installation method), additional axial fixation devices (such as stop rings or retaining rings) must be installed to prevent the tightening disc from accidentally disengaging due to vibration.

Protective cover reset: After installation, the protective cover must be reinstalled. For the ATEX version, the joint surface of the protective cover also needs to be coated with sealant.

Lubrication management: Oil selection and oil change cycle

Lubrication is the decisive factor in the lifespan of a gearbox. The manual provides an extremely detailed classification of oil selection and replacement cycles.

Oil compatibility: Bonfiglioli strongly recommends using PAG (polyethylene glycol) synthetic oil (such as Shell Omala S4 WE 320) or PAO (poly alpha olefin) synthetic oil. It is strictly prohibited to mix different brands or types of oil.

Oil level inspection: The oil level varies at different installation positions (B3, B6, V5, etc.). For models without overflow type oil level plugs (such as C12, C22, C32, and A05), a dipstick must be inserted into the dedicated hole for measurement. The measured value (X) must be less than the value corresponding to the installation position in Table 12/13 of the manual.

Oil change cycle (key data):

A70 and above/C/F/S series: If the oil temperature (t ₀) is below 65 ° C, mineral oil needs to be replaced in 8000 hours, and PAO/PAG synthetic oil only needs to be replaced in 25000 hours.

If the oil temperature is in the dangerous range of 80-95 ° C: the replacement cycle for mineral oil is shortened to 2000 hours (and continuous operation is not recommended), and for synthetic oil it is 12500 hours.

Practical operation suggestion: The first oil change should be carried out after 100 hours of operation to remove metal particles generated during running in. Afterwards, strictly follow the cycle corresponding to the oil temperature.

Long Term Stock: For equipment with the "LONG TERM STOCK" option and filled with anti rust oil:

Scenario A: If the rust proof oil is compatible with the mineral oil/PAO oil used later, simply add working oil.

Scenario B: If the rust proof oil is incompatible with the later used PAG oil (PAG is incompatible with mineral oil), the rust proof oil must be drained first, then about 20% capacity of PAG oil must be injected for a "washing test" - run empty for a few minutes, then drain, and finally add new PAG working oil.

Common troubleshooting and temperature monitoring

The manual provides a practical troubleshooting table (Table 18), which on-site engineers can use to quickly locate problems.

High bearing temperature: usually caused by low oil level, aging oil, or damage to the bearing itself.

High operating temperature: may be caused by high oil level, oil aging, or oil contamination.

Abnormal operating noise: may be caused by gear damage, excessive bearing wear, or excessive external load. Special attention: Loose installation bolts can also produce abnormal noise, which is extremely common under vibration conditions.

Oil leakage: It may be due to high oil level or seal failure. No leakage is allowed in ATEX environment as oil stains can adsorb dust and increase the risk of ignition.

Unable to start/output shaft not rotating: Check if the oil viscosity is too high (especially during low-temperature starting) or if the load is too heavy.

Surface temperature measurement protocol: In order to ensure ATEX compliance, the surface temperature at the interface between the gearbox and motor, as well as the area least affected by motor fan cooling, must be measured after 3 hours of full load operation. The maximum temperature difference Δ T shall not exceed 75K of the ambient temperature. If it exceeds this value, the machine must be stopped immediately and Bangfeili technical support must be contacted.