347 Flashcards
(25 cards)
Which of the following valve materials is the best choice for service conditions that include high pressures, high temperatures, and a corrosive fluid?
Stainless steel
If a valve must be removed frequently for service or repair, the valve to-pipe connection should be
Threaded
The first step in stopping leakage around the stuffing box of a gate valve is to
Tighten the gland bolt nuts
If the stem of a globe valve does not move freely, one likely cause is a
Damaged spot on the thread
What is usually the first indication of a valve problem?
Leakage
The first part of a diaphragm valve to wear out is usually the
Diaphragm
What causes a pop safety valve to open?
Pressure rising above a preset level
most pop safety valves, pressure and temperature conditions are usually limited to
250 psi and 450°F
Chatter in pop safety valves is caused by a ___ volume of flow at a ___ pressure
Low; High
What part of a safety relief valve contains the pressure that opens the valve?
A huddling chamber
A mechanism used to open or close a valve is called an
Actuator
The maximum air pressure for pneumatic diaphragm actuators is approximately
125 psig
Which of the following devices is used to measure fluid pressure?
Bourdon tube gauge
Which of the following indicates flow rate by producing an electrical signal?
Turbine flow meter
Accumulators are used for
Storing pressure
Applications that call for fully opened or fully closed positions are best handled by a ___ valve
Gate
The valve best suited for regulating flow is the ___ valve
Angle
Which of the following valve materials is most likely to be used in high-pressure, high-temperature conditions?
Steel
The marking “WOG” on the body of a valve stands for
Cold water oil gas
Flanged joints require the use of ___ to create an effective seal
Gaskets
One of the most common signs of insulation failure in steam lines is
Leakage
Condensate in a steam tracing system should be drained to the
Collection header
One of the disadvantages of electric tracers is that they
Require constant monitoring
The simplest and surest way to protect an exposed water line from freezing is to
Drain the line
