What is cylinder relief valve and function?

 

A cylinder comfort valve is a shielding system equipped on the pinnacle of the cylinder head that protects the engine and its environment from unheard of harm from overpressure. It is one of the several-cylinder head mountings mounted for the secure operation of an engine. As it is supplied to every cylinder of a marine engine, it lifts up, releasing extra combustion pressure. which protects the cylinder, cylinder head, and engine itself from the undesirable penalties of the ensuing combustion force. The valve operates when the cylinder strain exceeds its secure running limit. Under regular circumstances, it is locked in its role beneath the impact of a sturdy spring force. Now, when the combustion strain will become too excessive to raise the valve spindle; the valve will open, permitting the extra stress inside the combustion chamber to escape. The comfort valve is designed in such a way that the cylinder stress by no means exceeds 10% above the regular working pressure. A spring continues the relief valve in a closed situation while the lifting stress is adjusted by way of a fantastic packer thickness. Once operated, it releases the stress rapidly out of the cylinder, keeping off any damage. The valve and the spindle are separated in such a way that the valve can be placed effectively after opening.

What is cylinder relief valve?

A relief valve is a gadget used to restrict stress in one or more areas of a hydraulic circuit. A relief valve makes use of a spool or poppet engaged in the closed function by way of a spring. A spool is a cylindrical piece of machined metal that slides inside a machined body. A poppet is a flat piece of machined metal attached to a stem, and the face of the poppet rests towards the seat to provide the best sealing. A spool has higher metering characteristics, but drastically greater leakage than a poppet design. When stress rises in the element of the circuit where the relief valve is installed, pressure acts on the spool stop or poppet face; the pressure utilized by the spring opposes the pressure on the spool stop or poppet face to keep the valve closed. Valve spring compression pressure is regularly variable, and the peak can be decreased with the aid of an adjustable screw, although the range of variation is restricted (for example, a spring may be fine between 1,000 and 5,000 psi or between 100 and 1,200 psi, but hardly ever between one hundred and 5,000 psi).

 

cylinder relief valve

As hydraulic strain continues to push upward in the circuit where the valve is installed, pressure in opposition to the spool or poppet begins to overcome the opposing pressure of the spring, opening a flow direction to the tank. As pressurized fluid exits the comfort valve, electricity is diverted (in the structure of heat) until downstream strain equals the spring force, which ought to be a few drops of flow or all of the pump flow, depending on the utility and country of the circuit.

 

In short, a comfort valve is a hydraulic device designed to restrict strain on an entire gadget or sub circuit by means of diverting pressurized air to the reservoir. They are most frequently established without delay downstream of the pump to manage device pressure, but can be used in different components of the circuit to defend remote.

 

 

Function

 

To protect the cylinder against excessive pressure, the blow-off pressure should be adjusted 20–30% above the normal working load.

 

cylinder relief valve

main purpose is to lift when overpressure occurs in the combustion area; the resultant combustion gas is then expelled through a flared pipe to the deck.

 

 

Causes of the Relief Valve Opening

 

1) The maneuvering handle is moved too far, causing excessive fuel injection excessive. when too much fuel is supplied by the engineer when starting the engine.

 

2) If air is being used to stop the engine in an "emergency stop" situation.

 

3) Incorrect fuel pump timing causes overfueling.

 

4) Running the engine full astern for a prolonged period, in this case, the bridge should be informed that astern running is at its limit.

 

5) Incorrect adjustment of gas valve opening stress (low).

 

6) An incorrect governor setting causes over-fueling.

 

Fuel oils remain on top of the piston owing to:

 

A. Improper priming operation

B. Fuel valve renewal period

C. Fuel oil injected in a previous fail-start operation is still on the piston top.

 

Causes of lifting in service

 

1. Incorrect gasoline pumps timing, a inaccurate gasoline pump, or an incorrectly set gasoline injector turning in immoderate fuel.

 

2. The air-start valve stuck open or was timed incorrectly.

 

3. Incorrect camshaft timing, chain breakage, or governor fault, especially in heavy seas.

 

4. Badly leaking gasoline injector; via a unfastened nozzle or enlarged injection holes.

 

5. Water leaking into the combustion chamber.

 

6. Scavenge fire.

 

What should I do if the cylinder head relief valve is leaky or lifted?

 

Temporary measures

 

The leaking or lifting of the relief valve should be considered a serious issue and should be investigated. If the ship is maneuvering and the engine can't be stopped, the following temporary measures can be taken;

 

1. Rotate the spindle on its seat till leakage stops, in most cases, filth gathered on the seat can be pushed off.

 

2. A mild knock on the spindle can additionally assist end the leak.

 

3. Inform Bridge about the trouble and ask them to decrease stops and starts.

 

 

 

Permanent solution to a leaky relief valve

 

 Check for unit specific parameters such as exhaust temperature, scavenge pressure and temperature, CW outlet temperature, etc, If you have any reason to suspect abnormalities, investigate the cause further.

 

 If all parameters show up normal, end the engine in a secure spot, change the alleviation valve.

 

Take an indicator card and make certain the top stress is inside limits and different parameters are satisfactory.