In the machinery system operations of ships, safety is a crucial precondition. We need not only to protect the smooth operations of vessels but also to ensure the safety of the crew members. Among these integrated security components in the systems, the marine pressure relief valve is the most outstanding. It is almost used for handling all the highest-pressure machinery systems. These pressures may exceed the expected levels, and that causes situations beyond the Maximum Allowable Working Pressure(MAWP) or the designated working pressure.
When a ship sailing on the sea, various systems operate relying on pneumatics, hydraulics, air, or electronics. Thus, the construction and operation of a marine pressure release valve are vital. It is used to protect the valve can activate even though the control system is mistaken, and avoid overpressure conditions.
Generally speaking, the marine pressure relief valve is a critical fault protection mechanism. It can maintain the integrity and security of high-pressure systems on ships, particularly leading to potential dangerous and overpressure conditions when the control system is broken down.
Operating Mechanism of Marine Pressure Relief Valve
Operating based on the spring’s reaction to a specified operating pressure, the marine pressure relief valve functions as a crucial safety component. An adjustable screw atop the valve allows for fine-tuning the spring’s opening pressure. Under normal machinery operation, the spring’s tension prevents the valve from activating.
When pressure on the valve seat surpasses normal levels and counters the downward force of the spring, the pressure relief device lifts, releasing excess pressure until equilibrium is attained.
For unfired systems, the valve’s lifting pressure typically ranges from 8% to 15% of the working pressure, subject to manufacturer guidelines. Upon the system’s pressure returning to normal, the spring, set to activate at a specific pressure, closes the valve, restoring normal system operation.
In terms of safety, valves are designed for full lift to release excess pressure during sustained overpressure scenarios. Valves of this nature are commonly referred to as safety valves, with relief valves falling within this safety valve category.
Construction of Marine Pressure Relief Valve
The construction of a pressure relief valve for sale is a vital component within a ship’s safety system, designed for simplicity and reliability in varied operational conditions. These valves are crafted from robust materials capable of withstanding high temperatures, airflow, fluid dynamics, and corrosive environments.
Key components of the marine pressure relief valve include:
Body: Typically made of cast steel, the body houses essential parts like the valve spindle, valve, spring, and seat. It must withstand high pressures when the valve activates to release excess pressure.
Inlet & Outlet Connections: The relief valve’s inlet connects to the machinery or system, while the outlet connection varies based on the system type—either venting to the atmosphere for air systems, ducted outside the engine room for steam systems, or linked to an inlet or reservoir for hydraulic systems.
Diaphragm: Acting as a seal between the inlet/outlet connection and the valve body, the diaphragm prevents media leakage during relief valve operation.
Valve Seat: This component must be both soft to prevent valve damage and durable for extended operational life. Typically crafted from stainless steel coated with a soft metal layer to withstand pressure and corrosion.
Valve: Crucial for the controlled operation of the marine pressure release valve, the valve is usually constructed from stainless steel to ensure reliability.
Spindle/Plunger: Also known as the valve stem, the spindle attaches to the valve at the base, transferring the spring’s force to control the valve’s movement. Stainless steel is commonly used for the spindle material.
Spring and Adjusting Nut: The helical spring requires proper elasticity strength to facilitate correct valve opening and closing at set pressures. Adjustment bolts on the valve body allow for fine-tuning of the lifting pressure. Typically made from a steel alloy, the adjusting screw and spring ensure precise pressure regulation.
Selecting a Marine Pressure Relief Valve
When selecting a pressure relief valve for sale, several crucial parameters need evaluation:
Required Relief Pressures: Understanding the anticipated relief pressure is paramount, contingent upon the specific system or machinery where the relief valve will be installed.
Fluid Properties: Careful consideration of the chemical properties of the fluid is essential. Selecting suitable materials for the valve is crucial, as different fluids interact uniquely with various metals and materials. Optimal “wetted” components must be chosen to ensure compatibility with the fluid, especially for hazardous or flammable substances.
Materials: Material selection is influenced by fluid properties and application requirements. Common materials include brass, aluminum, and stainless steel grades. Springs, integral to the valve’s operation, are typically crafted from carbon steel or stainless steel. Stainless steel is favored for hazardous or corrosive fluids and high-temperature environments.
Flow Rate: Determining the flow rate is vital post-valve activation to ascertain the pressure release needed. Piping design, porting configurations, and orifice effectiveness are tailored based on the flow rate requirements.
Size & Weight: Space and weight constraints are significant considerations. Different systems may demand varying sizes of relief valves based on pressure relief needs. Port sizes, adjustment styles, and mounting options influence the overall size and weight of the valve.
