The main aim of the project is the automation of Blower K1201 used in the HYAM Plant of FACT using PLC. Thus we aim at developing an interlocking system which emphasizes on the design of interlocking facility,introduced to the safety parameters of the system, various control operations and entire system maintenance. The notion of this project came into our mind while considering the difficulties in the usage of the ordinary relay system for control of blower which has many limitations such as power consumption, complexity,lower speed,less flexibility etc.To overcome this problem PLC is introduced.
PHASES OF THE PROJECT
- Study of Blower K1201 : A basic study of blower K1201 and its related accessories was done.
- Study of relays and PLC : Basic study of relays, contacts and PLC was done.
- Software section : The logic diagrams were developed and software was tested.
STUDY OF BLOWER K1201
FACT Petrochemical Division consists of four main plants.They are HYAM plant, ANONE Plant, LACTAM Amine Sulphate Plant is used the manufacture Caprolactum.The Blower Kl20 l is used in this HYAM Plant.
Blower K1201 is manufactured by EBARA Manufactures in Netherlands and the model we are using here is 400TE05M. The type is Single Suction Overhung Type.This type of blower has impellers installed on the pinion shaft ends of the speed increasing gear unit.The ear unit is driven by an electric motor through a diaphragm coupling.The major function of the blower is used to feed air necessary for the combustion of Ammonia.
COMPONENTS ATTACHED TO THE BLOWER
The vertical split type blower casing made of cast iron permits inspection of the impeller and the blower casing interior when the suction casing is improved.The discharge casing is fixed to the gear casing.The blower casing is also equipped with lifting lungs and a drain.
The Titanium Impeller is single suction open type produced by milling art integrated solid body.It is coupled to the shaft by hydraulic press fit without keys.
Gears and shaft
Gear type is single helical, and in-volute curves are applied to tooth profile.As tooth surfaces are finished with a Maag gear grinder, and tooth profile of high precision with suitable correction is created, extremely quiet operation is obtained even at high speeds under a heavy loads.The piston is integral with the shaft, and a, thrust collar is provided on the opposite side of impeller. The material is nickel chrome steel, which is refined by heat treating in order to provide sufficient wear resistance. The heat treated chrome molybdenum steel gear is string fit to the carbon steel shaft.Both side of the shaft are provided with step differences to accommodate thrust.
The tilting pad type journal bearing on the high speed side completely suppresses self excited vibration such as oil whirl and oil whip which tends to occur at high revolution. There are different types of bearings such as radial bearing which on low speed consist of two arc metal split in to upper and lower halves, pocket bearings which on high speed side reduces mechanical loss at high speeds and a thrust bearing which on low speed side used for flat land construction.
The welded steel plates are split in to upper and lower halves with liquid gasket applied to the split surfaces. The lower casing consists of channels for delivery of lubricating oil to all bearings and tooth surfaces. The upper casing is provided with an air surface inspection window, seats for bearing thermometers. breather, tooth surface.
A diaphragm coupling between over drive gear and motor is used here.
Forced lubrication unit
the main components of this unit consists of shaft and oil pump, independent oil pump ,oil tank, oil cooler, oil strainer, oil pressure regulating valve, pressure I switch, level switch ,oil level gauge, oil pressure gauge and thermometer. This unit provides forced lubrication to overdrive motor bearings, tooth surfaces and motor bearing with a gear type oil. The pump is located at the shaft end of the lower drive gear an auxiliary independent gear type oil pump automatically provides lubrication during start and stop.The lubricating oil is fed to the bearing and tooth surfaces from the oil tank after filtering and cooling through the oil pump, oil cooler and oil tilter after which oil is return to the oil tank, oil pressure is regulated by an oil pressure regulating valve provided in this unit.
The controller device is a hydraulic type control device to perform compressor anti surge control. This controller device consists of a controller, a hydraulic pump, an electric motor, an oil tank, a ratio settling unit and other accessories which are assembled in one bod compactly. The discharge pressure of the blower and orifice or annular flow rate decreases and approaches to the surging ranged the anti surging controller opens to release a part of discharge air flow rate so as to prevent further decrease of suction air flow rate. Thus anti surging controller controls the blower to operate out of the surging range.
Here the motor used is squirrel cage induction motor .An induction motor is a type of ac where power is supplied to the rotor by means of electromagnetic induction. An electric motor converts electrical power in too mechanical power in its rotor. There are several ways to supply power to the rotor. In a dc motor this power is supplied to the armature directly from a dc source, while in an induction motor this power is indulged in the rotating device. An induction motor is sometime called as rotating transformer because the stator is essentially the primary aside of the transformer and the rotor is the secondary side. The primary side's currents evokes a magnetic fields which interact with the secondary side's emf to produce a resultant torque, hence forth serving the purpose of producing mechanical energy. Induction motors are widely used, especially poly phase induction motors, which are frequently used in industrial drives. Induction motors are now the preferred choice for the industrial motors due to their rugged construction , absence of brushes and the ability to control the speed of a motor.
The stator consists of wound 'poles' that carry the supply current to induce a magnetic field that penetrates the rotor . in a very simple motor, there would be a single projecting piece of the stator salient pole) for each pole, with windings around it; in fad to optimize the distribution of the magnetic fields, the windings are distributed in many slots located around the stator, but the magnetic field still has the same number of north south alteration. The number of 'poles' can vary between the motor types but the poles are always in pairs (i.e 2,4,6, etc. . .)
Induction motor are most commonly built to run on single phase or three phase power, but two phase motor also exist. In theory, two phase and more than three phase induction motors are possible; Many single phase motors having two windings and requiring a capacitor can actually be viewed as two phase motors, since the capacitor generates a second power phase 90 degree from the single phase supply and feeds it to a a separate motor winding. single phase power is more widely available in residential building, but cannot produce a rotating field in the motor(the field merely oscillates back and forth), so single phase induction motors must incorporates some kind of starting mechanism to produce a rotating field. They would , using the simplified analogy of silent poles. Three phase motors have three salient poles per pole number, so a four pole motor would have 12 salient poles this allows the motor to produce a rotating field allowing the motor to start with no extra equipment and run more efficiently than a similar single phase motor.
There are three types of rotor.
- Squirell cage rotor The most common rotor is a squarely cage rotor it is made up of bars of either solid copper or aluminum that span the length of the rotor, and those solid copper or aluminium strips can be shorted or connected by a ring or some times not, that is the rotor can be closed or semi closed type. The rotor bars in squirell cage induction motor are not straight . but have some skew to reduce the noise and harmonics.
- Slip ring rotor A slip ring rotor replaces the bars of the squarely cage rotor with winding's that art connected to slip rings. When this slip rings are shortened, the rotor behaves similarly to a squarely cage rotor; they can also be connected to resistors to produce a high resistance rotor circuit, which can be beneficial in starting.
- Solid core rotor A rotor call be made from a solid mild steel. The induced current causes the rotation.