|Fluid bed dryer automatic temperature control system is the original instrument and relay control equipment, the system in the course of the maximum heating temperature, the lower limit is quite different, is not conducive to the production. Equipment heater outer surface of the insulating layer is thin, the production of heat loss, dust removal device rings wire break easily, a lot of trouble in the maintenance process, in order to ensure the stable performance of the equipment, how to solve such problems? Fluid bed dryer for technical improvements.
After long-term production, fluid bed dryer in the structure, performance has significantly improved the quality is improving, but there are still some problems, following the production practice to improve the method.
(1) improvement of energy utilization
The fluid bed dryer is an air convection drying equipment from the formal, but there are still large energy consumption, and sealing equipment is not enough, by taking measures to achieve good energy saving effect. (1) to enhance the sealing effect of the device. Fluid bed dryer the original hopper with the device body using a flange connection, poor sealing effect. After the switch to the convex surface of the flange connection, the increase in the hopper and the sealing of the device body; (3) to increase the insulation measures. The heat exchanger shell to add insulation layer, the thickness of the insulation layer from the original 60mm to 150mm, and greatly reduce heat loss.
Improvement of the two pairs of trapping dust removal device
Boiling dryer trap bag shake vibration through the reciprocating motion of the cylinder to achieve the effect of dust, bag anti-static, non-fiber shedding cloth production, trapping bags with integral lifting the form. The filter bag to connect with clamp connection, hanging bars selected not easy deformation of rigid material, effectively extending the trapping dust removal device longevity, and reduced maintenance.
3 air distribution board (screen), improvements
Plates of airflow distribution in the fluid bed dryer has two roles, first, the supporting material layer, the gas evenly distributed. Distribution plate hole size, shape, distribution situation, the opening rate and so the fluid distribution plays a crucial impact. Gas distribution is uneven, make the bed "circulation" in its extremes easy to make the bed in some parts of "channeling", while the remaining parts of the death-bed, when most of the gas along the bed some channel in the form of short-circuit "channeling" through the bed to leave, so that the gas-solid contact with a significant deterioration, which should make efforts to avoid. Distribution board should be able to inhibit the uneven bed, that is, when some parts of the bed pressure drop reduces the flow velocity is increased, the resistance generated by the distribution board should be able to inhibit the increase in airflow, thus inhibiting flow deterioration.
Boiling dryer air distribution plate form of a single, vertical perforated plate or I-shaped stencil material in the flow process is prone to uneven fluidization or dead ends, and can not ensure that drugs in particle uniformity , while a single hole forms can not meet the requirements of the production process of different drugs. On the other hand, in order to reduce drug leakage material loss, and use the model of fluid dynamics, heat and mass transfer model, pitch, pore size, porosity and other parameters in the air distribution plate design, aerodynamics, thermodynamics simulation and validated to meet the requirements of the production process of different materials. Installation, the connection is made detachable, to ensure quick and thorough, complete cleaning.
On improving the air intake air handling
4.1 hot air mingling mouth set in the auxiliary engine room, and the heating device, the muffler installed together, the auxiliary engine room and the clean area to set straight the doors and windows, air cleanliness level of the auxiliary housing is often relatively low, will affect the medicinal hot air quality The device itself has a good purification device, otherwise not purify the air pollution drugs, it is difficult to meet GMP requirements.
4.2 equipment, air handling unit is configured to: Primary Filter - Efficiency Filter - (Asian) high efficiency filter. The air handling system configured with the early, medium and high efficiency filter, but with increasing run time, high efficiency filter will be blocked or damaged, the only judge from the appearance of up to identify whether the need to replace the lack of theoretical basis. Early replacement will increase the cost of postponed replacement will bring the risk of decline in air quality, thus affecting the quality of the product. Increase the pressure difference before and after the high efficiency filter the display device (Figure 2), replace the alarm when the pressure reaches the set value.
4.3 equipment, the induced draft fan and damper linkage, will lead the cause of the phenomenon of air reflux between the fan is switched off and the valve closed. Linkage through the fan start and stop with the air valve switch, the air valve open at a time when the fan start when the fan stops running, the air valve synchronization off, in order to ensure that no occurrence of air back.
5 improvement of the control system
Set the operating parameters of the equipment operator's experience-based, but is fully capable of intelligent, process parameters can be traced back, which put forward higher requirements on the device's electrical control system. In the electrical control system, you need to detect temperature, pressure, pressure, operating time, a series of devices and the underlying data, and then through the transmitter transmission and storage to the touch screen, the touch screen for data storage analysis and then develop a appropriate process route, you can achieve intelligent control.
Hot air heating control using the simple "open" and "off" mode, and stops when the temperature reaches the set value of steam, the heat exchanger there is still residual heat to the air temperature continues to rise, and vice versa, this will cause temperature fluctuations over , affecting the drying quality of the equipment. Through the PLC transformation temperature signal and processing, control the steam valve opening and closing, the temperature closed-loop control to achieve the purpose of self-control, control the size of the steam flow valve to maintain the level of the inlet air temperature, steam flow starts to heat up. the inlet air temperature close to the set value as soon as possible, and then automatically adjust the amount of steam to slowly close to the set value, and finally to maintain a stable amount of steam to the inlet air temperature to remain stable.
6 Concluding remarks
Start boiling dryer works, combined with some of the problems in the production process and equipment technology improvements, catching dust device, part of the temperature and inlet air filtration devices to improve and better meet the production requirements. Small transformation of the workload of the original system, without major changes to the original equipment, small investment, big return. Maximize the benefits!