Overview
The FMM Fertilizer Mixer Machine — FMM stands for Fertilizer Mixer Machine — is a fully automatic compost turning system developed for channel-type composting plants, mixing the material by tilling it and advancing it along the channel. It is designed to work in a channel roughly 2.5 metres wide; the machine is 6 metres long and 3 metres high (overall dimensions 3100 x 6400 x 3600 mm).
The machine consists of two main frames: the travel frame and the moving frame. The travel frame runs on the rails of the channel holding the material. The moving frame travels up and down on 2 cylinders attached to the travel frame.
Working Principle
The cylinders carrying the moving frame have a stroke length of 650 or 800 mm. The travel frame carries 4 motors of 1.1 kW (1400 rpm) with 22 rpm gearboxes. The moving frame carries 2 motors of 22 kW / 90 rpm, 4 fans of 0.21 kW and a 1.1 kW hydraulic unit. The 22 kW motors rotate the mixing assembly and perform the tilling operation.
Once the machine has finished tilling, it is returned from the end of the channel to the head of the channel as quickly as possible.
Head of channel: the product outlet side — End of channel: the product inlet side.
System Features
- The machine is operated by remote control; the automation supports remote access.
- The PLC-controlled power cabinet is located on the vertically moving platform of the machine, and the power control cabinet on its moving body.
- The system control panel is located in the operator room.
- Several machines can be controlled from a single controller.
- Visual value checks for the system are made on the PLC screen in the control cabinet.
- During tilling and travelling, the travel speed changes automatically according to the varying structure of the material, so the machine keeps operating safely.
- Temperature at the tilling point is measured automatically; the tilling movement will not start until the material has reached the required temperature.
- Air is delivered to the tilled area by 4 fans during tilling.
- In automatic mode, once the machine has completed tilling along the channel it rises, returns to the head of the channel, lowers again and continues mixing.
- In manual mode the material can be mixed by plunging into it at any point of the channel, so the machine can be used efficiently wherever mixing is found to be insufficient.
- During tilling, depth is measured with the help of linear guides and the material is tilled to the required depth.
- On the return run after mixing, levelling is carried out automatically with the linear guides to the dimension set.
- The current draw of the mixing motors, the travel speed setting and the instantaneous travel speed can be seen on the system control cabinet, which makes efficiency tracking and analysis easier.
- The system status is reported to the operator by a three-colour indicator lamp showing fault and operating condition.
- Operating hours and fault records are kept.
- The automation system can report information such as the position of the machine, the currents it draws, the plunge depth of the tines and operating hours.
- A GPRS modem is fitted for remote access. (The line agreement with the relevant GSM operator is arranged by the customer.)
- The setting and service pages are password protected.
- One spare system control unit is supplied.
Because the tilling and travelling speed of the machine varies with the structure of the material, the machine does not have a fixed cycle time.
Operating Scenario
The scenario below describes the behaviour of the machine when the channel is at full capacity.
Tilling Movement
When the machine is at the head of the channel, the moving frame is at the set upper position. In this position it detects the "start machine" command and sets the 22 kW motors in motion. With the start or travel command the cylinders are actuated and the moving frame descends at the required speed; integrated with the current draw of the 22 kW motors, the cylinder speeds automatically decrease when the set current is exceeded. The tines therefore plunge into the material and reach the bottom of the channel while pushing the material backwards.
Once the tines on the moving frame have reached the set plunge depth, the travel command begins. Along with the travel command, 4 fans are switched on. The travel speed can also be set manually.
During tilling, the current draw of the 22 kW motors is measured; when the set current value is exceeded, the speed of the travel motors is reduced and the machine is prevented from damaging itself. The machine has limit-switch stops at the head and the end of the channel.
Cylinder Movement
Two cylinders, positioned parallel and perpendicular to one another, move at the same speed and at the same time. The moving frame (approximately 5 tonnes), connected to the cylinders by a steel link chain, always runs strictly parallel to the travel frame — skewed or juddering operation is not acceptable. The cylinder position can be reported and is measured in order to set the plunge depth.
Travel Movement
The travel frame carries 4 wheels of 245 mm diameter and 4 travel motors, one at each corner. The drive from the motor is transmitted to the wheel by a module gear. In the event of a fault or failure of the travel motors, the responsible person is notified.
Temperature Measurement
During tilling, and depending on the customer's requirement, the machine stops travelling at the required points and, with the help of the 2 cylinders in front of it, immerses the measuring instrument into the material in the channel and analyses its temperature. If the temperature is suitable, tilling continues; if the required temperature is not reached, the machine goes to the stop position. While waiting in the stop position the machine keeps measuring and, when the set temperature value is reached, resumes tilling from where it left off.
Position Measurement and Reporting
The position of the machine in the channel can be reported in metres and viewed in real time on the control panel. The system records the plunge depth, the travel speed, the material temperature, the metres covered, the currents of the 22 kW motors and any faults, together with the day, month, year and time.
Fault Management
Faults that occur on the machine are reported to the operator on site in real time. The machine cannot be started until the fault has been cleared; once cleared, approval by the operator or the responsible member of staff is required. In addition, if the current of either of the two 22 kW motors falls below the standard operating current, the machine goes to the stop position and issues a warning indicating that the rotating assemblies need to be checked.
User Login
Depending on the customer's requirement, a username and password login can be created in order to report which operator is running the machines on a given shift.
Materials and Construction
- The structure is manufactured from ST-37 material and painted after shot blasting.
- The drive group shafts and guide rollers are manufactured from CK 45 steel.
- The gears and travel wheels are manufactured from C 4140 steel and induction surface hardened.
Cabinet and Electrical Equipment
Switchgear, buttons and switches together with the PLC and HMI are Siemens; the relay group is Phonex; the terminal group is Wago or Phonex. The control group is Elfatek so that it can run in synchronisation with the PLC. The electric motors are started synchronously via soft starters.