TRUCK-MIXERS

TRUCK-MIXERS
TRUCK-MIXER

                                                                                                        TRUCK-MIXERS

It is transported by special means called ready-made concrete truck-mixers and mixed in the truck-mixers to maintain its homogeneity until delivery. This mixing is carried out at different speeds depending on the concrete grade. Truck-mixers are designed and made to transport and unload concrete, gravel, sand or similar materials with a specific weight of no more than 2.4 kg/dm3. Truck-mixers are ready-made concrete transport and preparation tools.

 Classification of Truck-mixers

Truck-mixers are classified from 4m3 to 16m3 according to concrete carrying capacity.

Truck-mixers  are divided into dry system truck-mixers and age system truck-mixers according to the condition of  transporting and preparing the concrete  . The total volume of concrete threshing should not  exceed 80% for wet mixtures and 65% for dry mixtures.

Dry System Truck-mixers

Dry blended ready-made concrete, aggregate and cement are measured in the concrete plant and mixed in the plant or truck-mixer , and the water and its chemical additive, if any, are measured and mixed at the delivery site and added. In dry blended ready-made concrete, special attention should be paid to the amount of water given to the mixture and the mixing time on the construction site. Ø He can take the concrete he bought from the dry-ready concrete plant without turning it on the road.

The process of mixing concrete and watering is carried out on the construction site.

Drive systems are more powerful than others.

The water spraying system is made of concrete by giving water from 6-7 different places at the same time in the drum.

It requires more attention in the mixing and watering process, the operator should be more conscious. Water clocks should work correctly, the water drum is larger (2 tons). The shipping time is a maximum of 2 hours. The total volume of concrete threshing should not exceed 65% for dry mixtures.

Age System Truck-mixers

All its components, including water, are ready-made concrete measured and mixed in the concrete plant and must be molded within two hours at the latest.

Ready-made concrete is supplied with water in the plant. On the ready-made concrete road, the minimum (1 – 4 revolutions / minutes) also goes by turning the drum. The transport time is maximum 2 hours or 300 revolutions, the time can be extended by adding a delayer in advance if there is a possibility of exceeding the standard due to distance and failure.

Classification of Truck-mixers

Truck-mixers are classified from 4m3 to 16m3 according to concrete carrying capacity.

Truck-mixers are divided into dry system truck-mixers and age system truck-mixers according to the condition of transporting and preparing the concrete. The total volume of concrete threshing should not exceed 80% for wet mixtures and 65% for dry mixtures.

Dry System Truck-mixers

Dry blended ready-made concrete, aggregate and cement are measured in the concrete plant and mixed in the plant or truck-mixer, and the water and its chemical additive, if any, are measured and mixed at the delivery site and added. In dry blended ready-made concrete, special attention should be paid to the amount of water given to the mixture and the mixing time on the construction site.  He can take the concrete he bought from the dry-ready concrete plant without turning it on the road.Ø

The process of mixing concrete and watering is carried out on the construction site.

Drive systems are more powerful than others.

The water spraying system is made of concrete by giving water from 6-7 different places at the same time in the drum.

It requires more attention in the mixing and watering process, the operator should be more conscious. Water clocks should work correctly, the water drum is larger (2 tons). The shipping time is a maximum of 2 hours. The total volume of concrete threshing should not exceed 65% for dry mixtures.

Age System Truck-mixers

All its components, including water, are ready-made concrete measured and mixed in the concrete plant and must be molded within two hours at the latest.

Ready-made concrete is supplied with water in the plant. On the ready-made concrete road, the minimum (1 – 4 revolutions / minutes) also goes by turning the drum. The transport time is maximum 2 hours or 300 revolutions, the time can be extended by adding a delayer in advance if there is a possibility of exceeding the standard due to distance and failure.

The authorized plant supervisor must be consulted before adding the water lost due to evaporation during transportation at the construction site.

The total volume of concrete threshing should not exceed 80% for age mixtures.

Transmixrin Hydraulic System

Task

The truck-mixer hydraulic system is driven by the vehicle engine, allowing the drum to rotate at the desired speed and direction.

It ensures the operation of auxiliary systems, which are located according to the characteristics of the machine.

Parts Forming the System, Circuit Diagram

Hydraulic equipment consists of hydraulic pump (1), hydraulic motor (2), oil cooler (3), high pressure hoses (A) and (B), suction line hose (S), return line (R) and leak line (D).

Hydraulic Pump

Converts the energy transmitted by the self-propelled motor into hydraulic working energy. The pumps supply the oil required for the hydraulic system. The task of the hydraulic pump is to provide flow. The heart in the human body is replaced by pumps in hydraulic systems. The factors that determine the performance of hydraulic pumps are:

  • The rotational speed of the hydraulic pump (rpm).
  • The flow of oil sent by the hydraulic pump to the system (liters per minute).
  • The maximum operating pressure (bar or Psi) that the hydraulic pump can withstand mechanically.

Hydraulic Motor

They are elements that work in reverse of the hydraulic pump, converting the hydraulic energy of the oil into mechanical energy. The engine is driven by this oil and a rotational movement is obtained.

Pilot Pump

It ensures that the oil in the hydraulic cooler is not circulated in the system.

Safety Valve

Prevents the fluid sent by the hydraulic pump from exceeding the pressure specified in the hydraulic motor. This is due to a failure of the hydraulic motor, reduction and drum.

Oil Cooler

The high-performance oil cooler with filter, oil thermostat and electric cooling fan ensures that the hydraulic oil operates at the ideal operating temperature.

Operation of the System

The truck-mixers truck engine both allows the vehicle to walk and starts the hydraulic pump. The hydraulic pump gives the hydraulic motor oil in a closed circuit and rotates the hydraulic motor's inlet shaft pressurized. The hydraulic motor is connected to the gearbox that rotates the drum with a flan. The direction and speed of the accident can be changed by adjusting. If the environmental temperature is about 10 0C lower than the specified lowest temperature of the oil used, the system should be heated. For this purpose, in case of idling, the mixing drum is operated without being inserted into the stream for about 15 minutes.

Other Equipment of Hydraulic System

Hydraulic Pump Support

This newly developed support is mounted to cover almost all PTO (Power Take Off) pump positions and allow for comfortable maintenance.

Hydraulic System Half Ecological Cover

Especially when transporting the watery concrete in the drum in ups and downs or in rugged terrain, the hydraulic system is installed half ecological cover to prevent overflows that pollute the area during the journey or on the construction site.

Hydraulic System Full Ecological Cover

After filling dry material in the concrete plant, the mixing process in the mixing drum is the reason for dust coming out of the drum. This concealer cover completely resolves the problem.

Breakdowns and Symptoms

Fault Reason Correction

  • When the oil is hot, the mixer does not turn or rotates quite slowly.
  • The hydraulic pump is broken.
  • Replace the hydraulic pump. If there is material in the drum, fill the drum with as much oil and water as possible to delay the solidification of the content. Install the mechanical lock assembly of the drum, open the drum cover and drain as much material as possible to thoroughly wash and clean the inside of the drum. Separate the hoses from the hydraulic pump, then unscrew the pump.

When the oil is hot, the drum does not turn or rotates quite slowly (The pressure indicator shows high values in this type of load).

The hydraulic motor is broken.

Replace the hydraulic motor. If there is material in the drum, take the measures described above in the pump failure to delay the solidification of the contents, separate the hoses from the hydraulic motor, and then unplug the hydraulic motor.

If the hydraulic oil temperature is too high (80 – 85 0C)

  • The level of fat in the oil cooler is below the minimum.
  • The oil cooler reckless doesn't work.
  • It is the use of unsuitable oil.
  • The suction filter is clogged
  • It is the presence of oil leakage in the system.
  • Add oil of the same properties.
  • Make sure that the pin connecting the refrigerant propeller to the electrical cables is fully entered into the connectors.
  • Change the heat.
  • Replace the relays that activate the refrigerant propeller.
  • Replace the coolant fan.
  • Change the oil.
  • Change the filter.
  • Check the hydraulic unit, connections and pipe leaks. If there is sagging in the pipes, fix it, replace it if necessary.
  • If the drum does not rotate clockwise or counterclockwise
  • The hydraulic pump control cable is broken.

Change the cable. If the drum contains the material that needs to be emptied, operate the hydraulic pump directional control crowbar manually.

Vehicle PowerTrain Power Distribution Unit (PTO)

Task

At the exit of the engine, the power is transmitted to the vehicle's powertrains, but the truck-mixers need a power to function. For this purpose, with the help of a unit, the power in the engine output is replicated so that it can be taken from several points. This unit is called a power distribution unit (PTO Power Take off).

Location on Machine

The location of the PTO varies according to the manufacturers. The PTO takes its movement either directly from the flywheel gear or from the wandering gear in the gearbox. While mechanical energy from PTO is constantly moving the hydraulic pump in some models, movement transition is controlled with the grip system in some models.

Commissioning methods

  • Hydraulic
  • Pneumatic
  • Mechanic
  • Electric

Motion Transmission shapes

The hydraulic pump is connected to the PTO by a drive shaft or directly. With the commissioning of the PTO, the motion energy from the PTO moves the hydraulic pump. The hydraulic fluid directed by the pump guides the hydraulic motor that is activated at any time, allowing the drum to turn left or right.

Emergency Operating System

Task

In the event of damage to the diesel engine or hydraulic pump, an emergency system connected to the mixer can be used in another working state. Before using the emergency system, it is ensured that there is no further damage. It is the system used to empty the mixer in order to prevent solidification of the material inside the drum.

Drive shaft

Grease points

Connecting hoses, pressure and leak hoses are connected as in the way. "A and B" high pressure hydraulic hoses and "D" hydraulic leak line must be connected, ensuring that they are correctly positioned and screwing in the relevant records. MECHANICAL SYSTEM OF THE TRANSMICS

Drum

Task

Drums allow the homogeneous mixing and transportation of concrete cement, gravel, water, sand and various additives when necessary. Depending on the type of truck-mixers, the concrete carrying capacity is from 4 m3 to 16 m3.

The mixer drum is supported by two special steel reels fixed to the reduction box and rear console on the front console.

Construction Features and Considerations in Material Selection

Drums are usually made of abrasion-resistant steel alloys with a thickness of 5.5 mm. Drum material is cut without deformation with computerized optical machines and special twisted drum hair is combined with welding. It is preferred that the resources are the source of robot machinery. The drum balance is adjusted by controlling the drum lathe after the balance is taken in the balancing machine. The increase in drum life varies according to the quality of the material used. The resistance of the steel used in manufacturing allows to maintain the drum life and, moreover, to extend it. After the drum production is finished,  all surfaces are cleaned by sandblasting the drum with  grit. Grit opens small teeth on the hair surface, allowing the dye to hold onto the surface. After the necessary polling is done with steel paste, the entire surface is double primed with corrosion-resistant double-companeous epoxy primer and two-component anticorrosive filling power high epoxy primer. The adapted primer is 80–100 micron thick. After lining application, it is painted in the oven as a double layer with acrylic auto paint.

Importance of Helixes and Structure in Drum

Helixes mounted in the drum should be made in such a way that the prepared concrete is better mixed and emptied.

Drum inner spirals are assembled by special bending from the same material. Drum mixer helixes are worn at a certain speed depending on the mixed concrete dose and mixing process. The drum inner spiral is mounted on the lling so that it does not wear on them. Wear is more in the middle area of the drum. When the ends of the helix become very sharp, there is a tendency to form radial cracks towards the drum body. To prevent this, the ends are filled with eroded cracks welding. The total helix height should not fall below 25 cm.

Mixing pallets and helixes provide high quality mixture. As a result, a homogeneous mixture is obtained in all drum sections. Distinctive properties of the transplanted concrete (mixture) are maintained.

Drum Control Cover

It is used to perform wear control on in-drum helixes and mixing pallets in the interior of the drum. It has a linear structure in appearance. Because there are no protrusions on which the material will be stacked, and an oval-shaped thick seal also provides excellent sealing, since it is also used.

Importance of Drum Cleaning

Some residing concrete may remain in the drum at the end of the work, and this must now be cleaned in the drum to prevent the concrete from freezing. It is imperative to clean the parts of the drum in the interior of the drum that come into contact with concrete in the in-drum helixes and mixing pallets, and spray water should be used if necessary. At the end of the work, the mixer drum is filled with 150/200 liters of water. It is left spinning throughout the journey back to the property, then emptied and, if necessary, the process is repeated. At the end of each working day, it is ensured that there is no more concrete in the blender and these should be cleaned, if any. Concrete that freezes in the drum is an extremely difficult and laborious task to clean. Cleaning is done physically with hammers and crusher tools. The work of man in a closed and dusty area is dangerous in terms of health. If there is material in the blender, it should be filled with as much oil and water as possible to prevent the content from solidifying. The mechanical locking assembly of the mixer should be installed, the drum cover should be opened and as much material as possible should be emptied and thoroughly washed and cleaned inside the drum.

Carrier Reels

Task

The carrier rollers operate by contacting the ring. They ensure regular operation of the drum ring. Since the reels are a middle-middle-center system, the cradle system is available. It touches the drum ring from four regions, reducing the weight per reel to a minimum.

Structure

Carrier reels are made of sphero casting material. The reel is mounted on the bed with bushings and bearings, ensuring a comfortable rotational movement.

Location and Connecting shapes on the Machine

The machine is mounted on the rear console. Carrier reels are single and double system. Single-system ones work by contacting the ring from two regions. Dual-system ones work by contacting the ring from four regions.

Importance of Greasing Carrier Reels and Greasing

It is necessary to grease once a week (40 hours) with a grease gun to ensure the free rotating of the carrier reels and prevent them from jamming.

If the reels are jammed, they cannot be repaired in the truck-mixer, causing damage, to prevent this, the reels need to be replaced immediately.

Drum Return Ring

Task

It allows the drum in contact with the carrier reels to rotate environmentally.

Structure

The drum return ring is supplied by pulling from steel material. The ring is abrasion resistant and is one of the material that hardens as it is used. Especially when the drum is filled with concrete, the amount of load falling on it is too high and the weight of the less is carried in this section through the reels. It is used after turning system in precision machines. The ring is a pass system and therefore there is no possibility of cracking and breaking, it is resistant to deformation. It is replaced with a new one as needed.

Place on Machine

The drum return ring is located at the back of the drum.

Importance and Construction of Grease

The drum ring must be greased daily (8 hours) with the grease gun and checked every 200 working hours that the drum ring is working within the boundaries of the rollers. In greasing the drum ring, it is necessary to use excess oil with high-quality adhesiveness that is insoluble in water.

The drum ring and reel should be greased again after thorough cleaning during the periods in which the manufacturers appear.

Water System

Task

The mixture is obtained by giving water in the water system to ready-made concrete, aggregate (sand and gravel or crushed stone mixture), cement and additives, if any, which are included in the truck-mixer drum, and special attention should be paid to the amount of water and the mixing time in the mixture.

Structure

The structure of the water system is shown in figure 2.5. The water system consists of a tank (1) with a level indicator (2), a pump (3), water filling hose connection (6), filter (4), valve for filling the drum with water ( 7), water clock (8), drain valves (10), washing hose connection (9), washing hose connection (9), a filling pipe and a distribution pipe, which can be driven by a belt from the auxiliary diesel engine or mounted directly on the gearbox.

Water Pump

The reducer-mounted water pump has the capacity to pump 450 liters of water per minute.

If the water pump is connected directly to the gearbox by taking a safety precaution against overloads, the connection should be made with a coupling made of special plastic material. If the water pump is locked, the plastic container prevents more serious damage.

Water Tank

In truck-mixers, the capacity of water tanks is 1000 liters and different water capacities are also available. The water tank occupancy rate can be adjusted as desired. It is produced in stainless steel and pressure resistant.

Water in the water tank can be used for machine cleaning. Some companies do not recommend adding water to wet-ready concrete.

Water clock

It is mounted on the back of the transmix and allows the concrete in the drum to be transported without deterioration in a controlled manner.

  • Filling the Water Tank
  • The tank must be filled with water as follows
  • Make sure the mixer is turned off.
  • Make sure that the valve ( 5 ) is closed.
  • Make sure that the valve ( 7 ) is closed.
  • The drain valves (10) must be ensured to be closed.
  • The water filling pipe must be connected to the hose connection.
  • Valve (5) must be opened.
  • The water level in the tank can be controlled thanks to the level indicator (2) on the tank.
  • When the water flows through the drain pipe in the tank, the tank is completely filled.
  • Valve (5) must be closed.
  • The water filling pipe must be separated from the hose connection.

Considerations

  • The water pump should not be operated when there is no water in the system.
  • In winter, if there is a danger of freezing, the water in the system should be drained.
  • In systems powered by compressed air, the safety valve should not be tampered with with the pressure setting.
  • The water filter should be checked and cleaned every 200 hours.

Reducer

Task

It is a gear wheel system that resembles a gearbox but transmits the speed from the inlet shaft by reducing it to the exit shaft, while increasing the moment.

Structure

Hydraulic energy from the hydraulic pump comes to the hydraulic motor connected to the reducer. Hydraulic energy in the hydraulic motor is used to rotate the drum with the help of a reducer. The gearbox is fixed on the front console and soasses the drum. Mixing makes the drum rotate comfortably.

 

Maintenance of the Reducer

The fat in the reduction thread box is replaced by certain intervals. Metal detection and oil analysis can be made within the discharged oil to gain knowledge about the gears. In addition, if there is an abnormality in the working sound from the gears, the fault should be intervened before it grows further. When a fault is detected from the gearbox, the gears are replaced with a new one. Before the first operation of the transmix, care should be taken not to reduce the oil level in the reducer box below the red line.

Malfunctions

In case of any failure, if the reducer needs to be removed and there is material in the mixer, the necessary measures are taken to solidify the contents and the drum is cleaned. The hydraulic motor attached to the reducer is removed and then the gearbox is removed.

Fault Reason Correction

The cauldron isn't coming back.

The reducer is defective. Replace the reducer.

There's abnormal noises coming out of the gearbox.

There's an oil leak.

He's missing the seal.

Replace it with a new one.

Loosening flanch ports

The bolts are broken or loose.

Squeeze or replace it with a new one.

Properties Searched for in Oil Used

SAE Class 85W / 90 number gear oil is used. In the gearbox system, API GL 5MIL L 2105 D is used in oils.

Front Console

Task

It acts as a support for the truck-mixer drum in the front of the vehicle.

Construction Features

The body of the carrier feet is made of different thickness hair material and the connecting feet are made of special box profile. In order to increase durability, thicker material is loaded and reinforced in the interior. In addition to casting connections, there is additional connection on the front carrier legs. Carrier foot connection shoes are made of steel casting, studs are made of S8 quality round material.

Considerations and Controls to Be Considered at Chassis Ports

When connecting to the chassis, it should always be connected with the appropriate fasteners and the connection shape in the characteristics recommended by the manufacturer should be preferred.

Deformation and visible failures in the connecting legs should be repaired without neglect. In accordance with the manufacturer's instructions, a soft material is placed between the chassis ports of the front console. Fasteners are tightened at the end of certain working hours in line with the manufacturer's recommendations.

Rear Console

Task

It supports the truck-mixer drum from the back and carries it on other auxiliary systems.

Construction Features

The body of the carrier feet is made of different thickness hair material and the connecting feet are made of special box profile. In order to increase durability, thicker material is loaded and reinforced inside the rear carrier top roller connection plate is made of material 10 mm thick. In addition to casting connections, there is additional connection on the rear carrier legs. Carrier foot connection shoes are made of steel casting, studs are made of S8 quality round material.

Considerations and Controls to Be Considered at Chassis Ports

When connecting to the chassis, it should always be connected with the appropriate fasteners and the connection shape in the characteristics recommended by the manufacturer should be preferred. Deformation and visible failures in the connecting legs should be repaired without neglect. In accordance with the manufacturer's instructions, a soft material is placed between the chassis ports of the rear console. Fasteners are tightened at the end of certain working hours in line with the manufacturer's recommendations.

Stairs

Task

The slide-preventing steps and wide platform ensure a perfect view of ready-made concrete in the transmix without compromising safety. It is also used for cleaning and washing truck-mixer filling and drain grooves. Mechanical stairs are available on hydraulically controlled stairs as well.

Safety Precautions to Be Taken During Transportation

  • Connections should be made to ensure that the pop-up ladder is not opened while the truck-mixer is in motion.
  • Before moving the truck-mixer, it should be ensured that the ladder is folded and locked thanks to the hook placed for locking purposes.

Shaft

Task

Moment (torque) is used in the sense of rotational effort. shafts allow power in PTO to be transmitted to the hydraulic pump.

Structure

Shafts are usually made of empty shafts inside. The strength of the shafts made hollow increases and decreases. shafts are made of quality steels. They are very well balanced so that they are not affected by vibrations and that the rotating shaft at high revs can resist centrifugal forces. Welded particles on some shafts are balance weights.

Considerations for Dismantling and Installing

  • Safety and security measures should be taken.
  • The appropriate key and tool should be used.
  • Marking should be done before disassembly in order to install shaft connection flanges in the same direction.
  • Forks should be marked with shaft. When installing, care should be paid to the encounter of these signs.
  • Appropriate tightening torque should be used.

Drum Safety Lock System

The drum lock system must be installed before starting any maintenance process in the truck-mixer drum.