Dental compressor: which model for 1 to 25 dental chairs?

01The right question: how many chairs are working at the same time?

The Cattani manual for oil-free 1-2-3 cylinder compressors is clear: the choice of compressor depends on the instruments used or on the general compressed air requirements (Cattani compressors manual, ed. 02-2023, p. 11). So what matters is not the number of chairs installed, but the number of chairs drawing air at the same moment.

Cattani gives a concrete benchmark: one cylinder produces about 60 l/min at 5 bar and can supply an instrument consuming around 50 to 60 l/min at 2-3 bar (same source, p. 11). The manual adds that the compressor's air flow must be well above consumption, to allow the end-of-charge pauses needed to regenerate the drying column.

For large installations, Cattani states the basis of calculation on its data sheets: the recommendations for the AC 900, AC 1200 and AC 1800 are based on 55 N l/min per chair (Cattani AC 900, AC 1200 and AC 1800 data sheets).

Losses in the pipework count too

According to Cattani, pressure losses along the distribution network usually come from pipework that is not laid out as a closed circuit (ring) with a large cross-section. A ring circuit keeps the set pressure constant, and insulated copper pipework keeps the air clean and prevents condensation (Cattani compressors manual, p. 11). The diagram in the manual shows a Ø 20 mm ring with Ø 14 mm branches leaving from the top of the main pipe (p. 19).

02Cattani's recommendations, model by model

The table shows the values published by Cattani for the versions with dryer (air delivered at 5 bar effective, sound pressure level without cover).

Sources: Cattani product data sheets (cattani.it) and Cattani compressors manual, ed. 02-2023, pp. 5 to 7.

Single-phase or three-phase

The AC 100, AC 200 and AC 300 are available in 230 V single-phase and, for the AC 200 and AC 300, in 400 V three-phase (Cattani compressors manual, pp. 5 to 7). The AC 600 models are offered in three-phase (Cattani AC 600 data sheet). On axemed.be, each reference states its power supply: for example 013230 and 013235 for the AC 200, 013430 and 013435 for the AC 400.

Between 9 and 13 chairs, or more than 25

The data sheets reviewed do not give a recommended model for 9 to 13 chairs. For larger installations, Cattani states that it builds compressed air plants tailored to each requirement (Cattani compressors manual, p. 18). In that case, ask for a design study: contact AxeMed.

Need 8 bar?

Cattani also offers versions that deliver air at 8 bar effective (AC 310, AC 410, AC 610). Cattani presents the AC 310 as a three-cylinder compressor "for Cad-Cam"; it delivers 165 N l/min at 8 bar at 50 Hz (Cattani AC 310 data sheet).

03Why an oil-free compressor with an air dryer

Cattani explains that when high-quality air is required, it pays to use an oil-free compressor fitted with a drying system. The water-and-oil emulsion produced by a lubricated compressor impairs the operation of pneumatic instruments, especially rotary instruments, and even small traces can compromise a bond. According to the manufacturer, an oil-lubricated compressor combined with filters is less safe and probably more expensive in the end (Cattani compressors manual, p. 8).

What happens inside the machine

1. Air enters through the head filter, which removes dust and protects the piston and cylinder; this filter can be replaced by a HEPA H14 antibacterial filter.
2. The piston slides in the cylinder without lubrication.
3. The hot compressed air passes through an air/air heat exchanger: at around 20 °C ambient, the temperature difference stays at about 5 °C, which allows the water vapour to condense.
4. In the desiccant column, a cyclone collects the first droplets, then the air passes through a disc filter and silica gel that dries it.
5. On the way out, the air passes through a sintered bronze filter and then a HEPA H14 antibacterial filter before entering the tank, which is coated inside with a resin approved for food contact.
6. At the end of each charge, dry air flows back up the column in counter-current and regenerates the silica gel; everything is automatic.

Source: Cattani compressors manual, ed. 02-2023, pp. 9-10.

Pressure setting and noise

The tank pressure is factory-set between 5.5 and 7.5 bar for the 1-cylinder model and from 6 to 8 bar for the 2- and 3-cylinder models; Cattani warns that a higher maximum pressure increases stress and wear (p. 11). As for noise, the version with plastic protection (Q) reduces the level by about 10 dB(A) and the cabinet version by about 20 dB(A). Cattani asks that only the manufacturer's cabinets and covers be used, as they also provide protection against fire and explosion (p. 11).

The letters in the references read as follows: Q = plastic soundproofing cover with dryer, ND = without dryer, QND = plastic cover without dryer (Cattani compressors manual, pp. 5 to 7).

04The plant room: what Cattani requires

• Restricted access: the compressor and suction unit must be installed in a room closed to patients, unauthorised persons and untrained staff (Cattani compressors manual, p. 12).
• Temperature between +5 °C and +35 °C (p. 12). Above 35 °C, the air dryer cannot work properly (pp. 13-14).
• Electrical supply: a supply sufficient for the loads on the rating plate, with an earth connection, essential even in single-phase; no extension leads or multi-socket adapters (pp. 9 and 12).
• Floor drain connected to the sewer to collect liquids (p. 12).
• Nothing flammable in the room and no risk of corrosive, flammable or explosive mixtures (p. 12).
• Remote alarms: "machine stopped" or "temperature too high" signals must be relayed to an occupied room, with a visual and audible signal (p. 12).
• Space and cooling: in its training sessions, Cattani stresses a room large enough to move around the machine during maintenance, and a cooling system (Cattani technical documentation, 2022, p. 32).

What about outdoors?

The manual presents cabinet 010800 for 1-, 2- or 3-cylinder compressors: identical for all three models, it is suitable for indoor and outdoor use and can be exposed to sun, rain and frost, with an optional anti-freeze device (Cattani compressors manual, p. 17).

Installation must be carried out by an equipped, trained technician, who consults the instructions, performs the commissioning tests and trains users in routine maintenance (p. 12).

05Maintenance: filters, draining and periodic checks

What the practice does

• Periodically open the valve under the tank; if there is moisture, call a technician (Cattani compressors manual, p. 13).
• The compressor must not start when air is not being used: if it does, look for leaks in the network or equipment (p. 13).
• A machine that becomes noisier or vibrates indicates a loose or worn part: call the technician (p. 13).

What the technician does

• Periodic check every 6 or 12 months depending on the workload, using original spare parts only (p. 14).
• Check of electrical current draw every six months and of the intake of each cylinder: the air drawn in must not be less than 6,000 N l/h (p. 14).
• Fan check every 12 months (p. 13).
• Head filters: in a clean environment, replacement every 12 months is sufficient; in a dusty room, clean the fans often and replace the filters much more frequently (pp. 13-14).
• Replacement of the HEPA H14 filter, according to the instructions supplied with the filter (p. 14).

The Cattani poster on extraordinary maintenance lists the head filter references: polyester filter 168563 (particles down to 20 µm) and HEPA H14 antibacterial filter 168429. It states a service life of about 10,000 hours for the bearings and about 5 years or 5,000 hours for the anti-vibration mounts, under normal conditions (Cattani poster "Manutenzione straordinaria aspiratori e compressori", 12/2016). Part-by-part details are in our guide Original Cattani parts and filters.

→Products mentioned

AC 100 – One-cylinder compressor, with air drierRef. 0131303 219,00 € excl. VATAC 200 – Two-cylinder compressor, with air drierRef. 0132303 824,00 € excl. VATAC 300 – Three-cylinder compressor, with air drierRef. 0133304 589,00 € excl. VATAC 400 – Twin-cylinder, twin-head compressor, with 2 air driersRef. 0134307 149,00 € excl. VATAC 600 – Three-cylinder, twin-head compressor, with 2 air driersRef. 0135358 144,00 € excl. VAT

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