What is the purpose of piping?
Provided housing for which fluids and in some cases solid matter, are transferred from one place to another.
What are eight design factors for piping?
- Fluid temperature
- Fluid pressure
- Fluid volume-mass flow rate
- Chemical properties of the fluid
- Physical properties of the fluid
- Fluid contamination
- Shock loads
- Changes in direction
What are six common pipe materials?
- Low-carbon steel – Rust easy but is low cost and easy to work with
- Low – alloy steel – cost more and hard to work with great resistance to work fatigue and corrosion used in hot temp situations.
- Stainless steal – corrosion resistance used when process. Purity is essential.
- Copper alloy (brass, bronze) - excellent corrosion resistant properties, electrical and thermal conductivity properties and good workability
- Nickel alloy (Monel & inconel)– used with high temperatures and pressures and equipment such as heat exchangers, steam generators and condensers.
- Plastic – used for water drainage systems and chemicals.
What are piping support restraints?
Any device designed to support a load or control its movements. Support restraints must allow the pipe to make whatever movement is needed to minimize stress on the piping system.
What are the four DO NOTs and/or precautions for piping support restraints?
- Do not climb on them
- Do not attach any rigging, valve chains, etc. to them
- Do not adjust them in anyway
4 do not remove them for any reason
What’s the purpose of thermal insulation?
Improves plant efficiency and reduces heat loss. It also adds to plant safety protecting workers from hot surfaces.
What’s the purpose of thermal loops?
Loops and bends are designed to allow for expansion and contraction of the piping systems. The piping loops or bends allows for thermal linear expansion.
What’s the purpose of piping expansion joints?
Expansion joints are used to protect piping systems from thermal linear expansion.
What causes water hammer?
A change in velocity of any flowing liquid.
When the liquid reaches a component, Valve, or the end of the piping, a damaging force will be exerted on the component or piping as the water is suddenly stopped or retarded.
State the five principal functions of valves?
- Starting or stopping flow.
- Regulating and throttling flow
- Preventing backflow
- Regulating pressure
- Relieving pressure
What are the major components of a valve?
- Body- houses individual valve parts and directs flow.
- Bonnet-guides the valve stem, aids w/sealing.
- Stem-rod extends thru bonnet & drives the disc(open/closing element) into the seat.
- Disc-opening closing element determines the amount of flow through valve.
- Seat-mating surface of the disc prevents flowed when the two contact.
- Packing-material that seals the gap between the valve stem and the bonnet.
- Packing gland-compresses the packing.
- stuffing box-houses the packing.
- Valve actuator– designed to operate valves or assist in positioning of the valve disc.
What are the four types of valve actuators?
Manual, electrical, hydraulic, pneumatic
What are the two types of stems?
Rising and non-rising
Most widely used valve in piping. Needed as a stop valve, fully shut off or fully on. Used for ON-OFF Control of fluid system?
Gate valve
A valve specifically designed for controlling or regulating flow?
Globe valve– have shorter disc travel and therefore far fewer turns to open close than a gate valve of the same size
A valve with a ball shaped disc with a hole through its center?
Ball Valve-a hole through the center of the disc provides straight through flow with minimal turbulence, low torque, and tight closure. Used for start-stop or throttling flow control.
Extremely durable, efficient, reliable valve that may be used as a control or isolation valve.
Butterfly valve – can go from fully closed fully open with a quarter turn or 90° turn
A valve use in systems containing chemical or radioactive contaminated water or gases. Normally low-pressure low-temperature application range of 50 psi and 180-220°F. Block or control type valve or isolation or block type.
Diaphragm Valve.
A unique valve that requires no packing too seal. Design to allow zero leakage. Not designed for reverse flow. not designed for throttling. Only used for on-off applications.
Kerotest valve
Valve used to prevent reverse flow?
Check valve.
What are the two types of check valves?
- Swing check-disc swings out of the way when flow is applied on it.
- Lift check-System flow pushes up on the disc, lifting it off the seat and the valve closes by gravity or reverse flow.
This is used in lines where It is necessary to reduce incoming pressure to required service pressure?
Pressure regulator
Define fail safe position?
Is defined as the desired position the valve will assume upon failure of the input power to the valve actuator.
What are the methods for determining valve position?
Stem position-actual stem position.short stem is closed.
local remote indicators- control room or local arrows lights.
system conditions-touch, feel, sound of system.
