Classification of Truck Mixers
Transmixers are classified from 4m3 to 16m3 according to their concrete carrying capacity.
Truck mixers are divided into two as dry system truck mixers and wet system truck mixers according to the concrete handling and preparation conditions. The ratio of concrete batch volume to total volume should not exceed 80% for wet mixes and 65% for dry mixes.
Dry System Truckmixers
Dry-mixed ready mixed concrete is the concrete whose aggregate and cement are measured at the concrete plant and mixed in the plant or in the transmixer, and its water and chemical additives, if any, are measured and mixed at the delivery site. In dry-mixed ready mixed concrete, special attention should be paid to the amount of water given to the mixture at the construction site and the mixing time. It can take the concrete from the dry ready mixed concrete plant without turning it on the road.
Mixing and quenching of concrete is done on site.
Propulsion systems are more powerful than others.
The water spray system is made of concrete by giving water from 6-7 different places in the boiler at the same time.
More attention is required in mixing and quenching, the operator should be more conscious. The water clocks should work correctly, the water boiler is larger (2 tons). Shipping time is a maximum of 2 hours. The ratio of concrete batch volume to total volume should not exceed 65% for dry mixes.
Wet System Truck Mixers
All components including water are ready mixed concrete measured and mixed in the concrete plant and must be poured into the mold within two hours at the latest.
Water is supplied to the ready-mixed concrete at the power plant. Ready-mixed concrete goes on the road by turning the boiler at a minimum (1 – 4 revolutions / minute). The transportation time can be extended by adding a retarder beforehand if there is a possibility of exceeding the standard due to a maximum of 2 hours or 300 cycles of transportation, distance and malfunction.
The ratio of concrete batch volume to total volume should not exceed 80% for wet mixes.
Hydraulic System of Truck Mixer
The transmixer hydraulic system is driven by the vehicle engine and enables the boiler to rotate at the desired speed and direction.
It ensures the operation of auxiliary systems according to the characteristics of the machine.
WATER TANK STAIR BOILER ADDITIONAL GUTTER OIL COOLER
Parts of the System
It converts the energy transmitted by the motor driving it into hydraulic working energy. The pumps supply the necessary oil for the hydraulic system. The job of the hydraulic pump is to provide flow.
They are the elements that work opposite to the hydraulic pump and convert the hydraulic energy of the oil into mechanical energy. The engine is driven by this oil and a rotational movement is obtained.
It allows the oil in the hydraulic cooler to be circulated in the system.
It prevents the fluid sent by the hydraulic pump to exceed the pressure specified in the hydraulic motor. This occurs due to a fault in the hydraulic motor, reducer and boiler.
The truck engine of the truck mixer not only allows the vehicle to move but also operates the hydraulic pump. The hydraulic pump delivers oil to the hydraulic motor in a closed circuit and pressurizes the input shaft of the hydraulic motor. The hydraulic motor is connected to the gearbox that rotates the boiler with a flange. The rotation direction and speed of the boiler can be changed by adjusting. If the ambient temperature is approximately 10 0C lower than the specified minimum temperature of the oil used, the system must be heated. For this, the mixing vessel is operated for about 15 minutes in the idling state of the engine without being put into the stream.
Other Equipment of the Hydraulic System
Hydraulic Pump Support
This newly developed support has been installed to cover almost all PTO (Power Take Off) pump positions and to allow comfortable maintenance.
Hydraulic System Half Ecological Cover
Especially when transporting the hydrated concrete in the boiler on bumpy or rough terrain, the hydraulic system half ecological cover is installed to prevent overflows that pollute the environment during the journey or at the construction site.
Hydraulic System Full Ecological Cover
After the dry material is filled in the concrete plant, the mixing process in the mixing vessel is the cause of dust coming out of the boiler. This concealer cover completely solves the problem.
Vehicle Powertrain Power Distribution Unit (PTO)
At the output of the engine, the power is transmitted to the vehicle's powertrain, but the truck mixers need power to operate. For this purpose, with the help of a unit, the power at the motor output is increased so that it can be taken from several points. This unit is called power distribution unit (PTO Power Take off).
Location on the Machine
The location of the PTO differs according to the manufacturers. The PTO takes its movement either directly from the flywheel or from the idler gear in the gearbox. While the mechanical energy taken from the PTO moves the hydraulic pump continuously in some models, the motion transition is controlled by the clutch system in some models.
Ways of Commissioning
Motion Transmission forms
The hydraulic pump is connected to the PTO with a drive shaft or directly. With the activation of the PTO, the motion energy taken from the PTO moves the hydraulic pump. The hydraulic fluid directed by the pump directs the hydraulic motor, which is activated when desired, and allows the boiler to turn to the right or left.
MECHANICAL SYSTEM OF THE TRANSMIXER
Boilers provide homogeneous mixing and transport of concrete cement, gravel, water, sand and, if necessary, various additives. Depending on the type of truck mixers, the concrete carrying capacity is from 4 m3 to 16 m3.
The mixing bowl is supported by the reduction box on the front console and by two special steel rollers fixed on the rear console.
The Importance of Helix and Its Structure in the Boiler
The helices installed in the boiler should be made in such a way as to ensure better mixing and discharge of the prepared concrete.
Boiler inner spirals are assembled from the same material by special twisting. Boiler mixer helices wear at a certain rate depending on the mixed concrete dose and mixing process. The blade is mounted on the inner helix of the boiler to prevent wear. Wear is more in the middle of the boiler. When the ends of the helices become too sharp, there is a tendency for radial cracks to form towards the boiler body. To prevent this, cracks with worn ends are filled with welding. The total helix height should not fall below 25 cm.
Mixing paddles and helices provide high quality mixing. As a result, a homogeneous mixture is obtained in all boiler sections. The distinctive properties of the transported concrete (mixture) are preserved.
Carrier rollers work by contacting the rotation ring (ring). They ensure the regular operation of the boiler ring. There is a cradle system as the reels are a movable system from the bottom bracket. By contacting the boiler ring from four areas, it minimizes the weight falling on each reel.
Boiler Return Ring (Rotation Ring)
It enables the boiler, which is in contact with the carrier rollers, to rotate circumferentially.
Mixture is obtained by giving water in the water system to ready mixed concrete, aggregate (mixture of sand and gravel or crushed stone), cement and additives, if any, taken into the transmixer boiler, special attention should be paid to the amount of water in the mixture and the mixing time.
The water pump mounted on the reducer has the capacity to pump 450 liters of water per minute.
If the water pump is directly connected to the gearbox by taking a safety measure against overloads, the connection must be made with a coupling made of special plastic material. The plastic coupling prevents more serious damage if the water pump locks up.
The capacities of water tanks in truck mixers are 1000 liters and different water capacities are also available. The water tank fill rate can be adjusted as desired. It is produced from stainless steel and resistant to pressure.
The water in the water tank can be used for machine cleaning. Some companies do not recommend using it to add water to wet ready mixed concrete.
It is mounted on the back of the truck mixer and allows the concrete in the boiler to be transported in a controlled manner without deterioration.
It is a gear wheel system that is similar to a gearbox as a system, but transmits the speed from the input shaft to the output shaft by reducing it, while increasing the torque.
The hydraulic energy from the hydraulic pump comes to the hydraulic motor connected to the reducer. The hydraulic energy in the hydraulic motor is used to rotate the boiler with the help of the reducer. The reducer is fixed on the front console and supports the boiler. It enables the mixing vessel to rotate easily.