MAO twin-shaft mixers

The MAO range covers twin-shaft mixers from 0.5 to 9 m³ of vibrated concrete output per cycle and meets every production capacity requirement. Their performance is recognised in ready-mix concrete, prestressed and precast elements, RCC concrete for dams, soil stabilisation, and also in inertisation, waste treatment and chemical products. Depending on the application, the mixers can be equipped with accessories and options that optimise productivity, mixing quality and service life. Where needed, we develop new solutions together with the customer.

Price on request.

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SICOMA MAO twin-shaft mixer with inspection platform and stairs

SICOMA MAO twin-shaft mixer – mixing drive and gearbox

Key features

13 sizes, from MAO 750/500 to MAO 13500/9000
Vibrated concrete output from 500 to 9000 l per cycle
Hourly capacity from 20 to 360 m³/h
Ni-Hard cast iron liner plates and mixing blades, 530 HB minimum
Inspection platform with stairs included as standard
SWOD swing-out drives available as an option

Technical specifications

Model	MAO 750/500	MAO 1500/1000	MAO 1875/1250	MAO 2500/1670	MAO 3000/2000	MAO 3750/2500	MAO 4500/3000	MAO 5000/3350	MAO 6000/4000	MAO 7500/5000	MAO 9000/6000	MAO 12000/8000	MAO 13500/9000
Dry filling capacity (l)	750	1500	1875	2500	3000	3750	4500	5000	6000	7500	9000	12000	13500
Vibrated concrete output per cycle (l)	500	1000	1250	1670	2000	2500	3000	3350	4000	5000	6000	8000	9000
Cycle time (loading excluded) (s)	90	90	90	90	90	90	90	90	90	90	90	90	90
Hourly capacity (vibrated concrete) (m³/h)	20	40	50	67	80	100	120	134	160	200	240	320	360
Mixing motor (kW / HP)	15 / 20	37 / 50	45 / 60	55 / 75	2 x 37 / 50	2 x 45 / 60	2 x 55 / 75	2 x 75 / 100	2 x 75 / 100	2 x 90 / 125	4 x 55 / 75	4 x 75 / 100	4 x 90 / 125
Hydraulic power pack motor (kW / HP)	0.75 / 1	1.5 / 2	1.5 / 2	1.5 / 2	1.5 / 2	2.2 / 3	2.2 / 3	2.2 / 3	2.2 / 3	2.2 / 3	2.2 / 3	4 / 5.5	4 / 5.5
Maximum aggregate size (mm)	0÷80	0÷150	0÷150	0÷150	0÷180	0÷180	0÷180	0÷180	0÷180	0÷180	0÷180	0÷180	0÷180
Mixing shafts speed (rpm)	27	25	25	25	25	25	25	25	25	25	25	25	25
Mixing blades (pcs)	12+2+2	8+2+2	8+2+2	12+2+2	12+2+2	16+2+2	16+2+2	16+2+2	20+2+2	20+2+2	28+2+2	36+2+2	36+2+2
Weight of empty mixer (without skip) (kg)	1900	4900	5000	6000	7500	9000	9470	9750	11900	12200	14750	19600	24000
Weight of empty mixer (with skip) (kg)	—	7000	7200	8100	12000	12485	13850	14250	22000	—	—	—	—
A – maximum width (mm)	1490	2000	2000	2000	2320	2320	2600	2600	2600	2600	2600	2600	3000
B – maximum height (mm)	1246	1940	1940	1940	2135	2135	2155	2155	2155	2155	2415	2415	2650
C – maximum length (mm)	1946	2825	2825	3124	3509	4047	4076	4076	4480	4674	6330	7094	7150
D – height of top cover (mm)	228	458	458	458	458	458	458	458	458	458	458	458	458
G – standard discharge door length (mm)	500	740	740	740	1520	2090	2090	2090	2540	2540	2540	2958	2958
G1 – reduced discharge door length (mm)	—	—	—	—	740	740	740	740	1040	1040	1520	2540	2540
G2 – double discharge door length (mm)	—	—	—	—	630	740	740	740	1040	1040	1310	1520	1520

Construction

Extra-rigid tank: The stiffened frame of the tank eliminates the risk of deformation during transport (including in a container) and during full-load operation, and guarantees the correct planarity of the shaft seals. The metal frame for the aggregate hopper and the scales can be placed directly on the mixer without additional supports.
Gearboxes: The gearboxes of the mixing group are of the epicyclic type. The first reduction is carried out by a pulley transmission with a constant-velocity universal joint that keeps the shafts synchronised. The low input speed to the gearboxes allows the lubricating oil to work at a low thermal load. The connection between the gearbox and the tank is made with the exclusive connection sleeve, developed over the years to make any maintenance on the shaft supports easier and faster. This sleeve can be removed easily to give access to the shaft support, so in case of maintenance the plant downtime is minimised.
Mixing elements: The mixer tank is lined with Ni-Hard cast iron of 530 HB minimum hardness. The mixing arms, with a low profile to avoid material build-up, are made of spheroidal cast iron. The mixing blades are made of Ni-Hard cast iron of 530 HB minimum hardness. The large number of blades, their position and their orientation guarantee the right combination of rolling and circulation of the material during mixing.
Alarm box: The mixer is equipped with several sensors: thermal sensors for the motors and gearboxes, level gauges for the gearbox oil and the hydraulic power pack, and level and pressure sensors for the automatic lubrication system. On request, SICOMA can supply the Black Box, an electronic system that records the type, number and duration of possible anomalies and alarms during mixer operation. The same device can be programmed for preventive maintenance.
Automatic lubrication: The grease needed by the seal to keep the counter-rotating disks lubricated is supplied by a timed pump to the progressive dispenser, which distributes the required quantity of grease (6 g/h) evenly to each seal. A high-efficiency filter removes possible impurities when the grease tank is refilled through its connector.
Top cover and inspection platform: The high top cover (500 mm) has two hinged hatches and no posts. It allows easy access to the mixer for thorough cleaning at the end of the shift or for preventive and unscheduled maintenance, resulting in a shorter plant shutdown. The inspection platform with stairs, included in the supply, is essential for safe inspection and maintenance of the mixer. Its effective modular design makes installation extremely easy without a crane or winch.
Shaft supports and seals: The modular support patented by SICOMA is made with two separate housings. The bearing is lubricated in a long-lasting oil bath. The seal, based on the exclusive counter-rotating disk system, is lubricated with liquid grease under controlled pressure.
Hydraulic power pack: Door closing is guaranteed by the pressure sensor included in the hydraulic circuit. In case of failure or a power cut, a manual pump can be operated for emergency discharge and closing.
Discharge door: The discharge door has a rubber seal that runs along its full perimeter. The eccentric rotation of the door sector guarantees that the rubber seal is always reached and compressed despite wear.

Accessories

Standard accessories: All MAO mixers are supplied with the following standard accessories: liner plates and mixing blades made of Ni-Hard cast iron; mixing arms made of spheroidal cast iron, bolted to the shafts; high top cover with inspection hatches and ports; inspection platform with stairs; wiring of all auxiliary devices to an IP55 junction box and alarm box with the related sensors and probes; automatic grease lubrication system with electric pump and progressive dispenser; safety key transfer lock for accident prevention, compliant with CE standards.
Optional accessories: On request, MAO mixers can be equipped with the following accessories: discharge chute; dust collector bag (airbag); double speed for skip ascent and descent; pre-assembled feeding system with aggregate holding hopper, cement scale and water scale, complete with a holding frame that rests on the four sides of the mixer tank; special customisation for dams and large RCC projects.
Skip hoist: The aggregate loading skip is available for MAO mixers up to size 6000/4000. The hoist has two grooved drums on the same shaft. The skip cable has an anti-free-fall block in case of cable failure, while two limit switches constantly check its tension. On request, double speed for ascent and descent is available, as well as an inverter-based controller to customise the speed.
Batch feeding system: Thanks to its particularly reinforced structure, SICOMA twin-shaft mixers can be equipped with a batch feeding system stacked on the tank, using the top fixing plates on the tank frame. The system consists of an aggregate holding hopper, cement scale, water scale and airbag. Everything is pre-assembled at the factory before shipment, so installation time on site is extremely short.

Options

Swing-out drives (SWOD option): This unique option for SICOMA twin-shaft mixers was developed over recent years to make maintenance on the shaft supports easier and faster. The complete drive assembly (motor, pulleys and gearbox) is hinged to the side of the mixer tank and can be swung out easily without cranes or any lifting device. In case of unplanned maintenance, plant downtime is minimised, resulting in extremely low maintenance cost.
Slow motion drive: This option is based on an auxiliary motor that can rotate the shafts at low speed (1 rpm). Using a button switch, the shafts can run safely even with the inspection doors open. Cleaning and regular maintenance (such as periodic blade adjustment) are simpler and faster. We recommend choosing the manual control panel, which includes all devices for operating the slow motion drive.
High-pressure washout: Two high-pressure water pipes are placed above the shafts, with as many nozzles as there are arms. These spray bars are driven by a gearmotor and rotate so that the jets reach every spot for effective cleaning. Washout must be carried out at the end of each mixing cycle and the waste water is used for the next mixing.
High-pressure water unit: With a reservoir of at least 200 litres, the high-pressure water unit supplies the spray bars installed in the mixers using a piston pump driven by a motor of at least 15 kW. Pressure and flow rate are selected according to the mixer size (minimum 60 bar).
Reduced discharge door: The reduced size of the discharge door allows the use of a small discharge chute. As a result, the mixer support structure can be shorter than on standard twin-shaft mixers.
Bomb bay door: All SICOMA twin-shaft mixers can be equipped with the bomb bay door, which allows the bottom of the mixer tank to be opened over nearly half of its surface. Discharge is extremely fast even with low-slump concrete. This option is particularly important for RCC production and loading onto dump trucks.
Double discharge door: The mixer can be equipped with two independent discharge doors to pour concrete in two different places. This overcomes one of the limitations of twin-shaft mixers.
Manual control panel: The mixer can be equipped with a manual control panel that operates the mixer in manual mode with the following buttons: start/stop of the mixer motors, open/close discharge door and emergency stop. The panel can also operate the slow motion drive, if present.

Notes

Productivity: To determine mixer productivity, two parameters must be considered: the maximum weight of the mix, based on the usual specific weight of concrete (150 lb/ft³ or 2400 kg/m³), and the maximum volume occupied by all batch components charged into the mixer, which must not exceed the dry filling capacity.
Technical data: The hydraulic power pack motor size may vary according to the discharge door type. All technical data are subject to change without notice due to technical improvements. The values indicated do not apply in all applications and conditions and are subject to variation depending on the use and quantity of the product.