- What is the pressure at the base of a pipe 1” diameter and 1’ high? What would the pressure be in a pipe 1n diameter and 275’ high? SPO 6-7-8 BOW 2-3-4
A column of water 1’ high exerts a pressure .433 psi at its base.
275 x .433 = 119 psi
- What is a lantern ring? SPO 6-7-8 BOW 2-3-4
It is a spacer between the packing rings allowing liquid to be used for packing cooling and to prevent the escape of the liquid being pumped.
- Why use flexible couplings between the pump and the power source? SPO 6-7-8
The pump will run quieter with less wear and will be easier to align. The flex coupling will dampen start up shock and may act as a shear if the pump seizes.
- What should ph in a steam boiler be? What should ph in a hot water boiler be? What if your condensate return had a ph of 6.5 and what should it be? SPO 6-7-8 BOW 23-4
ph in a steam boiler should be 10.5 to 11.5
ph in a hot water boiler should be 8 to 8.5
ph is corrosive. Condensate ph should be 8 to 8.5
- What is a closed feedwater heater? What are its advantages and disadvantages? SPO 6-7-8 BOW 2-3-4
heater in which feed water and steam are in separate compartments or spaces. The heat is transferred through a metal wall from the steam to the water.
Advantage: It heats feed water to within a few degrees of the steam temperature.
Disadvantage: It does not remove air from the feedwater and is easily fouled.
- What is an open feedwater heater? What are its advantages and disadvantages? SPO 6-7-8 BOW 2-3-4
A heater in which the feedwater and steam mix. The steam gives up its heat to the feedwater as it condenses.
Advantage: it removes most of the 02 and C02 from the feedwater.
Disadvantage: it only heats water to about 225 F.
- Where should the feedwater pump be in relation to a feedwater heater and why? SPO 6-7-8 B0W 2-3-4
The pump is placed before a closed feedwater heater to handle cooler water and force it through the heater so nothing becomes steam bound.
The pump is placed after an open feedwater heater and water must flow to the pump under a static head. A pump placed before an open feedwater heater will flood the heater.
- Which type of feedwater heater heats the water the hottest? SPO 6-7-8
A closed feedwater heater which will often heat the water to within a degree or two of the steam heating it.
- What type valves and in what order are used on a feedwater line? LPB 2 3 BOW 2-3-4
From the feedwater tank, stop valve, pump, stop valve, automatic valve, stop valve, bypass around automatic valve with globe valve, check valve, stop valve then into the boiler.
- Name three types of pipe used in steam plants. What is the temperature and pressure allowed for standard fittings? SPO 6-7-8
Standard, Extra strong, Double extra strong or schedule 40, 80, 160.
125 psi and 450 F
- What type of pipe is used for superheated steam? If a boiler operating at 175 psi. has a super heater Installed what changes will be made to the cast iron valves and fittings? SPO 6-7-8
Only schedule 160 can be used for superheated steam.
No cast iron is allowed on superheated steam.
They will be replaced with iron or steel
- If you installed a steam line that is 100’ long, where would you place the anchoring? How is expansion taken care of in steam lines? SPO 6-7-8 BOW 2-3-4
Anchor the pipe on each end, with an expansion joint in the middle, with rollers supporting the pipe.
Expansion bends, sliding sleeves, corrugated joints.
- Name three ways to overcome vibration in piping. Give three reasons for insulating pipe. SPO 6-7-8
Air chambers, vibration eliminators and support the pipe more securely.
To save fuel and energy, prevent sweating and for safety.
- What are one-pipe, two-pipe, and three-pipe systems? Name the pipes in a three-pipe system. What is the main disadvantage of a one-pipe system? BOW 2-3-
A One Pipe System has only one pipe; both steam and condensate go through the same pipe.
In a Two Pipe System the steam is in one pipe and the condensate in the other.
In a Three Pipe System the pipes can be steam supply, gravity condensate return and vacuum condensate return.
The main disadvantage in a one-pipe system is that it allows air to collect in the system causing corrosion.
- What is a Hartford loop? (Handout)
It is a loop of piping to protect a boiler in case of rupture in the condensate return line.
- Which is larger, the steam or condensate lines and why? Should a steam line slope? Why and which way? SPO 6-7-8
Steam Lines. Steam has more volume.
YES, to prevent standing condensate.
The slope should be with the steam flow and toward a trap.
- Describe three types of steam traps. SPO 6-7-8 LPB 2-3 BOW 2-3-4
Inverted Bucket: The steam and condensate enter at the bottom and flow upward into the inverted bucket. As condensate enters the trap it displaces steam in the bucket, which sinks, causing the valve to open. The condensate is blown out the valve, the bucket again floats and the valve closes. Any air caught in the trap passes through a small orifice in the bucket preventing the trap from becoming air bound.
Float and thermostatic: As the float rides up on the condensate, it will open the valve. The valve closes as the level falls. Air will cool the trap, as it cools, the thermostatic valve will open, passing the air through.
Thermostatic trap contains a bellows expanding when exposed to the heat of live steam forcing a plug into an orifice closing the valve. As condensate cools the trap the bellows contracts, opening the valve and discharging the condensate.
- What device is installed upstream of the steam trap? Give two reasons for a steam trap to leak through. SPO 6-7-8 LPB 3 BOW 2-3-4
A strainer.
Dirt keeping the trap orifice open or broken internal parts.
- What will happen when a steam trap gets stuck closed? And if stuck open? LPB 2-3 BOW 2-3-4
If closed, equipment will fill with condensate, lose efficiency and could be damaged by hammering or freezing.
If open, steam will fill the condensate lines, pressurizing the condensate system. It will waste steam.
- List 6 places where steam traps should be installed. Where is an inverted bucket trap used most? SPO 6-7-8 BOW 2-3-4
- Steam radiators
- Heat exchangers
- Drip legs
- Steam headers
- Before PRVs
- Before automatic valves
Where steam lines turn up
- How often should steam traps be tested for proper operation and list 5 ways of testing them? LPB 2-3 BOW 2-3-4
They should be tested frequently and at first sign of underheated heat exchangers, increased condensate temps and pressurized receivers.
Temperature drop in and out, listening device, temperature crayons, flow indicators, test valves and knowledge of the equipment. (Handout)
- What is the difference between a gravity return system and a vacuum return system? SPO 6-7-8 LPB 2-3 BOW 2-3-4
In a gravity system, condensate is returned to the boiler feed tank by the tendency of water to flow downhill.
In a vacuum return system, condensate is returned to the boiler feed tank by a pump.
- List three things a vacuum return pump on a condensate system does. BOW 2-3-4
- Pulls standing condensate back to the receiver making the system more efficient.
- Vents air from the system.
- Pushes condensate to the boiler or boiler feed tank.
- What are the advantages of a feedwater heater? SPO 6-7-8 LPB 2-3 BOW 2-34
It will lessen the thermoshock damage to the boiler, it will save BTUs and it can remove free oxygen
