4BE3 U3 C1 Matching
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Match the type of pressure relief valve with its characteristic:

Relief Valve = Gradual opening, used for incompressible fluids Safety Valve = Rapid opening, used for compressible fluids Pressure Relief Valve = Acts on inlet static pressure, recloses after normal conditions Temperature and Pressure (T&P) Relief Valve = Actuated by pressure or temperature at the valve inlet

Match the pressure relief valve type with its application:

Safety Relief Valve = Compressible or incompressible fluids Relief Valve = Incompressible fluids Temperature and Pressure (T&P) Relief Valve = Temperature and pressure sensitive systems Pressure Relief Valve = General purpose pressure relief

Match the term with its definition from ASME PTC-25:

Pressure Relief Valve = Acts on inlet static pressure, recloses after normal conditions Temperature and Pressure (T&P) Relief Valve = Actuated by pressure or temperature at the valve inlet Relief Valve = Gradual opening, used for incompressible fluids Safety Valve = Rapid opening, used for compressible fluids

Match the standard with its description:

<p>ASME PTC-25 = Relates to pressure relief devices and their definitions ASME BPVC I, Part PG-73.1.4 = Specifies pressure relief valve designs and operations</p> Signup and view all the answers

Match the type of fluid with the suitable pressure relief valve:

<p>Compressible fluids = Safety Valve Incompressible fluids = Relief Valve Compressible or incompressible fluids = Safety Relief Valve High-temperature fluids = Temperature and Pressure (T&amp;P) Relief Valve</p> Signup and view all the answers

Match the characteristic with the type of pressure relief valve:

<p>Rapid opening = Safety Valve Gradual opening = Relief Valve Actuated by pressure or temperature = Temperature and Pressure (T&amp;P) Relief Valve General-purpose pressure relief = Pressure Relief Valve</p> Signup and view all the answers

Match the valve type with its purpose:

<p>Safety Valve = Relieve compressible fluids Relief Valve = Relieve incompressible fluids Temperature and Pressure (T&amp;P) Relief Valve = Relieve pressure and temperature Pressure Relief Valve = Relieve excess pressure</p> Signup and view all the answers

Match the type of pressure relief valve with its operation:

<p>Pressure Relief Valve = Acts on inlet static pressure, recloses after normal conditions Temperature and Pressure (T&amp;P) Relief Valve = Actuated by pressure or temperature at the valve inlet Relief Valve = Gradual opening, used for incompressible fluids Safety Valve = Rapid opening, used for compressible fluids</p> Signup and view all the answers

Match the following components of a safety valve with their corresponding functions:

<p>Huddling chamber = Increases the effective area of the disc Lip (skirt) = Forms a small compartment to fill with steam when the valve starts to open Guides = Allow the valve disc to move only in a vertical direction Blowdown adjusting rings = Control the size of the huddling chamber escape port opening</p> Signup and view all the answers

Match the following terms with their corresponding definitions:

<p>Blowdown = The difference between actual popping pressure of a pressure relief valve and actual reseating pressure Popping pressure = The pressure at which the valve suddenly lifts and opens fully Reseating pressure = The pressure at which the valve closes Set pressure = The pressure at which the valve is designed to open</p> Signup and view all the answers

Match the following scenarios with their corresponding effects on the safety valve:

<p>Huddling chamber escape ports fully open = The valve recloses with less drop in boiler pressure Huddling chamber escape ports blocked = The boiler pressure must drop significantly for the valve to reclose Blowdown adjusting ring in an intermediate position = The valve recloses at a pressure in-between the above scenarios Compression spring compressed = The valve opens with a greater force</p> Signup and view all the answers

Match the following regulations with their corresponding requirements:

<p>ASME BPVC I, Part PG-72.1 = A minimum blowdown of 2 psi (15 kPa) or 2% of the set pressure ASME PTC-25 = Defines blowdown as the difference between actual popping pressure and reseating pressure ASME BPVC I, Part PG-73.2.4 = Prevents debris from entering the valve disc and affecting its operation Jurisdictional Boiler Inspector = Installs a wire seal to prevent tampering with the blowdown adjustment</p> Signup and view all the answers

Match the following components with their corresponding purposes:

<p>Compression spring = Provides the force to close the valve Valve disc = Moves vertically to open or close the valve Huddling chamber = Increases the effective area of the disc Threaded adjustable annular rings = Adjust the blowdown of the valve</p> Signup and view all the answers

Match the following scenarios with their corresponding effects on the valve:

<p>Steam rushes into the huddling chamber = The valve lifts and opens fully Steam escapes from under the lip = The valve recloses Pressure under the lip increases = The valve stays open Pressure under the lip decreases = The valve closes</p> Signup and view all the answers

Match the following components with their corresponding functions:

<p>Lip (skirt) = Forms a small compartment to fill with steam Guides = Prevent the valve disc from shifting horizontally Huddling chamber = Increases the effective area of the disc Blowdown adjusting rings = Control the escape of steam from under the lip</p> Signup and view all the answers

Match the following terms with their corresponding effects on the valve:

<p>Increased force against the compression spring = The valve opens fully Decreased pressure under the lip = The valve closes Increased pressure under the lip = The valve stays open Steam escaping from under the lip = The valve recloses</p> Signup and view all the answers

Match the following components with their corresponding purposes:

<p>Valve disc = Opens or closes the valve Huddling chamber = Increases the effective area of the disc Blowdown adjusting rings = Adjust the blowdown of the valve Compression spring = Provides the force to close the valve</p> Signup and view all the answers

Match the following components with their functions in a safety valve:

<p>Jam nut = To loosen before adjusting the pressure Adjusting nut = To increase the popping pressure Spindle = To connect the discharge pipe Spring = To compress to increase the blowoff pressure</p> Signup and view all the answers

Match the following scenarios with their corresponding effects on the valve:

<p>Steam builds up under the lip = The valve opens fully Steam escapes from under the lip = The valve recloses Force against the compression spring increases = The valve opens Force against the compression spring decreases = The valve closes</p> Signup and view all the answers

Match the following safety valve characteristics with their corresponding values:

<p>Operating pressure = Up to 1720 kPa Steam temperature = Up to 230°C Material selection = Cast-iron Valve type = General-purpose</p> Signup and view all the answers

Match the following safety valve installation requirements with their corresponding locations:

<p>Drum = Mount safety valve in an upright position Superheater = Connect safety valve to the boiler independently Reheater inlet and outlet headers = Place safety valve as close as possible to the boiler Discharge pipe = Leave ample room for expansion</p> Signup and view all the answers

Match the following safety valve regulations with their corresponding sections:

<p>Design and material selection = ASME BPVC I Installation requirements = ASME BPVC I, Part PG-71 Testing and adjustments = ASME BPVC, Section VII Capacity and sealing = ASME BPVC I</p> Signup and view all the answers

Match the following safety valve adjustments with their effects:

<p>Screwing the adjusting nut down = Increase the popping pressure Screwing the adjusting nut upwards = Decrease the spring compression Loosening the jam nut = Increase the blowoff pressure Compressing the spring = Decrease the popping pressure</p> Signup and view all the answers

Match the following safety valve components with their positions:

<p>Spindle = Above the spring Adjusting nut = Below the spring Jam nut = On the spindle Discharge pipe = Below the valve</p> Signup and view all the answers

Match the following ASME BPVC codes with their corresponding regulations:

<p>PG-67.1 = Minimum number of pressure relief valves required for a boiler PG-67.2 = Pressure relief valve capacity for each boiler PG-67.4 = Exception to pressure relief valve capacity PG-68.1 = Pressure drop upstream of each pressure relief valve</p> Signup and view all the answers

Match the following safety valve characteristics with their corresponding materials:

<p>Cast iron = Used for lower pressures and lower temperatures Steel = Used for superheaters operating over 230°C Alloy steel = Used for superheaters operating over 230°C Bronze = Prohibited for superheaters operating over 230°C</p> Signup and view all the answers

Match the following safety valve components with their corresponding functions:

<p>Valve disc = Rises slightly from the seat when steam pressure reaches set point Coil spring = Holds the valve disc tightly against the seat Try lever = Manually lifts the valve Nut L = Adjusts the point at which the valve will lift</p> Signup and view all the answers

Match the following safety valve regulations with their corresponding temperatures:

<p>ASME BPVC Section I, Part PG-68 = Superheaters operating over 230°C ASME BPVC Section I, Part PG-73 = Boilers operating over 230°C ASME BPVC Section I, Part PG-67 = Electric boilers with a power input over 1100 kW</p> Signup and view all the answers

Match the following safety valve characteristics with their corresponding effects:

<p>Rapid opening = Relieves compressible fluids Normally used to relieve compressible fluids = Characterizes a safety valve Exposed spring = Prevents high temperature steam from affecting the spring Flange connections = Facilitates installation and maintenance</p> Signup and view all the answers

Match the following safety valve components with their corresponding purposes:

<p>Seat = Valve disc rises slightly from this when steam pressure reaches set point Spring J = Holds the valve disc tightly against the seat Nut L = Adjusts the point at which the valve will lift Cap B = Prevents access to the adjusting nut</p> Signup and view all the answers

Match the following safety valve regulations with their corresponding capacities:

<p>PG-67.2 = Discharge all steam without allowing pressure to rise more than 6% above maximum allowable working pressure PG-67.1 = Minimum capacity required for electric boilers with a power input over 1100 kW PG-68.1 = Pressure relief valve capacity for superheaters PG-73 = Capacity requirement for boilers operating over 500 ft2</p> Signup and view all the answers

Match the following safety valve characteristics with their corresponding applications:

<p>Safety valve = Used for saturated and superheated steam service Cast iron safety valve = Used for lower pressures and lower temperatures Steel safety valve = Used for higher pressures and higher temperatures Bronze safety valve = Used for refrigerant receivers</p> Signup and view all the answers

Match the following safety valve components with their corresponding actions:

<p>Try lever = Manually lifts the valve spindle Valve spindle = Connected to the valve disc Nut L = Adjusts the compression of the spring Cap B = Prevents access to the adjusting nut</p> Signup and view all the answers

Match the following safety valve regulations with their corresponding requirements:

<p>ASME BPVC Section I, Part PG-68 = Superheater and reheater pressure relief valves must be constructed of steel or alloy steel ASME BPVC Section I, Part PG-67 = Electric boilers with a power input over 1100 kW must have a minimum of two pressure relief valves ASME BPVC Section I, Part PG-73 = Boilers operating over 230°C must have a minimum of two pressure relief valves</p> Signup and view all the answers

Study Notes

Pressure Relief Valves

  • Automatically open to relieve pressure and then automatically reclose
  • Exist in many different varieties, with 11 types defined by ASME PTC-25 Pressure Relief Devices
  • Each type has distinct operating characteristics and applications

Types of Pressure Relief Valves

  • Pressure Relief Valve: designed to actuate on inlet static pressure and reclose after normal conditions have been restored
  • Temperature and Pressure (T&P) Relief Valve: actuated by pressure at the valve inlet or by temperature at the valve inlet
  • Relief Valve: characterized by gradual opening, generally proportional to the increase in pressure, used for incompressible fluids
  • Safety Relief Valve: characterized by rapid opening or gradual opening, used for compressible or incompressible fluids
  • Safety Valve: characterized by rapid opening, used to relieve compressible fluids

Requirements for Boilers

  • Each boiler shall have at least one pressure relief valve
  • Boilers with more than 500 ft2 of bare tube water-heating surface or electric boilers with a power input more than 1100 kW shall have two or more pressure relief valves
  • Pressure relief valve capacity shall be such that the valve will discharge all the steam that can be generated by the boiler without allowing the pressure to rise more than 6% above the highest pressure at which any valve is set

Superheater and Reheater PRVs

  • Pressure drop upstream of each pressure relief valve shall be considered in the determination of set pressure and relieving capacity of that valve
  • Superheater PRV must open before the drum PRVs do and close after the drum PRVs

Safety Valve Construction

  • Made of cast iron, steel, alloy steel, or bronze
  • Used for relieving compressible fluids, commonly found on steam boilers, steam lines, compressed air vessels, and refrigerant receivers
  • Consists of a spring that holds a valve disc tightly against a seat, which opens when the steam pressure reaches the set point pressure

Safety Valve Operation

  • Valve disc has a lip (skirt) that forms a huddling chamber, which fills with steam when the valve starts to open, increasing the effective area of the disc
  • When the valve lifts, the pressure of the steam acts on this increased disc area, resulting in a greater force against the compression spring, causing the valve to pop wide open
  • The valve will remain open until the pressure drops to below the popping pressure

Blowdown

  • Defined as the difference between the actual popping pressure of a pressure relief valve and the actual reseating pressure, expressed as a percentage of set pressure or in pressure units
  • Minimum blowdown of 2 psi (15 kPa) or 2% of the set pressure is required by ASME BPVC I, Part PG-72.1

Installation of PRVs

  • Safety valves mounted on the drum, superheater, reheater inlet and outlet headers must be placed in an upright position with the spindle vertical
  • Must be connected to the boiler independent of any other steam connection, and located as close as possible to the boiler without any unnecessary intervening pipe or fitting

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Description

This quiz covers the different types and functions of pressure relief valves, including their construction, operation, and purpose. Learn about the various categories and terms used to describe these valves.

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