Skip to main content

Construction and Working Principle of Indicator

  • An engine indicator consists of a small bore cylinder containing a short stroke piston which is subjected to the same varying pressure that takes place inside the engine cylinder during one cycle of operations.
  •  This is done by connecting the indicator cylinder to the top of the engine cylinder in the case of single-acting engines, or through change over cocks and pipes leading to the top and bottom ends of the engine cylinder in the case of double-acting engines.
  • The gas pressure pushes the indicator piston up against the resistance of a spring, a choice of specially scaled springs of different stiffness being available to suit the operating pressures within the cylinder and a reasonable height of diagram.
  • A spindle connects the indicator piston to a system of small levers designed to produce a vertical straight-line motion at the pencil on the end of the pencil lever, parallel (but magnified about six times) to the motion of the indicator piston.
  • The “pencil” is often a brass point, or stylus, this is brought to press lightly on specially prepared indicator paper which is scrapped around a cylindrical drum and clipped to it.
  • The drum, which has a built-in recoil spring, is actuated in a semi-rotary manner by a cord wrapped around a groove in the bottom of it; a hook at its lower end to a reduction lever system from the engine crosshead attaches the cord, passing over a guide pulley.
  • Instead of the lever system from the crosshead, many engines are fitted with a special cam and tappet gear to reproduce the stroke of the engine piston to a small scale.
  • The drum therefore turns part of a revolution when the engine piston moves down, and turns back again when the engine piston moves up, thus the pencil or stylus on the end of the indicator lever draws a diagram which is a record of the pressure in the engine cylinder during one complete cycle.

Labels:

Comments

Post a Comment

If you have any doubts.Please let me know

Popular posts from this blog

Main engine interlocks

Interlocks are provided so that the engine can be started or reversed only when certain conditions have been fulfilled. When there is a remote control of engines, it is essential to have interlocks. This reduces the possibility of engine damage and any hazards to the operating personnel. Turning gear Interlock . This device prevents the engine from being started if the Turning gear is engaged. Running Direction Interlock . This prevents the fuel from being supplied if the running direction of the engine does not match the Telegraph. Starting Air Distributor in end position . This prevents starting from taking place if the shifting of the Distributor has not been completed. Main Lube. oil pressure, Piston cooling pressure, Jacket water pressure, and important parameters must be above the required minimum. Auxiliary Blower Interlock . The Auxiliary Blower is provided in case of Constant pressure turbo charging. Air Spring pressure Interlock . In case of the present generation...
8 comments
Read more

Differences between MC/MC-C and ME/ME-C engines

The electrohydraulic control mechanisms of the ME engine replace the following components of the conventional MC engine: Chain drive for camshaft Camshaft with fuel cams, exhaust cams and indicator cams Fuel pump actuating gear, including roller guides and reversing mechanism Conventional fuel pressure booster and VIT system Exhaust valve actuating gear and roller guides Engine driven starting air distributor Electronic governor with actuator Regulating shaft Engine side control console Mechanical cylinder lubricators. The Engine Control System of the ME engine comprises: Control units Hydraulic power supply unit Hydraulic cylinder units, including: Electronically controlled fuel injection, and Electronically controlled exhaust valve activation Electronically controlled starting air valves Electronically controlled auxiliary blowers Integrated electronic governor functions Tacho system Electronically controlled Alpha lubricators
15 comments
Read more

Manganese bronze is not typically used as a propeller material .Why

1. High cost: Manganese bronze is a costly alloy, making it less economical for large propellers. 2. Low strength-to-weight ratio: Compared to other propeller materials like nickel-aluminum bronze or stainless steel, manganese bronze has a lower strength-to-weight ratio. 3. Susceptible to corrosion: Manganese bronze can corrode in seawater, especially when exposed to high velocities and turbulence. 4. Poor cavitation resistance: Manganese bronze is more prone to cavitation damage than other materials. 5. Difficult to cast and machine: Manganese bronze is challenging to cast and machine, making it less desirable for complex propeller geometries. 6. Limited weldability: Manganese bronze has poor weldability, making repairs and modifications difficult. Nickel-aluminum bronze or stainless steel are commonly used for propellers due to their: - High strength and durability - Excellent corrosion resistance - Good cavitation resistance - Ease of casting and machining - Weldability
88 comments
Read more