Single-Stage Regulators Quiz

Questions and Answers

Which flame type is characterized by having a lower temperature than a neutral flame?

Carbonizing flame (correct)

Oxidizing flame

Combustion flame

Neutral flame

What is the flame temperature of a neutral flame?

3470°C - 3500°C

3000°C - 3086°C

3090°C - 3100°C

3087°C - 3090°C (correct)

What indicates the amount of excess acetylene in a carbonizing flame?

The color of the flame

The length of the flame

The temperature of the flame

The amount of feather on the cone (correct)

In which flame type is oxygen left over after combustion?

Oxidizing flame Signup and view all the answers

What occurs at the point where the feather just disappears in a flame?

Achieving a neutral flame Signup and view all the answers

What is a primary disadvantage of single-stage regulators?

They do not provide fine control over the delivery pressure. Signup and view all the answers

Which component is common to both single-stage and two-stage regulators?

Outlet connection Signup and view all the answers

What pressure range does a two-stage regulator typically reduce cylinder pressure to in the first step?

1241 kPa to 2758 kPa Signup and view all the answers

In what applications are two-stage regulators commonly used?

Gas feeding to sensitive instrumentation and lab conditions. Signup and view all the answers

What is the function of the seat mechanism in a regulator?

To control the flow and pressure of gas. Signup and view all the answers

What is the appropriate action to take if a regulator malfunctions?

Send it to an authorized service center for repairs Signup and view all the answers

What does creep in a regulator indicate?

Gas is leaking past the seat due to improper seating Signup and view all the answers

Which of the following is a symptom of creep?

Regulator leaks from the relief valve Signup and view all the answers

Which method should NOT be used for repairing a hose?

Using tape to seal the leak Signup and view all the answers

Why should copper tubing not be used to repair acetylene hoses?

Copper can form an explosive mixture with acetylene Signup and view all the answers

What should you do if a flashback burns a hose?

Discard the entire hose Signup and view all the answers

Which practice is important for handling industrial quality regulators?

Observing safe handling practices Signup and view all the answers

What is the recommended method for checking hoses for leaks?

Test by immersing the hose in water under pressure Signup and view all the answers

What is a potential consequence of attempting torch repairs without proper training?

Damage to equipment and serious injury Signup and view all the answers

Which maintenance practice is NOT recommended for torch tips?

Using as hammers Signup and view all the answers

In the oxyacetylene outfit setup, what should be done after securing the cylinders?

Remove the cylinder caps and arrange the cylinders Signup and view all the answers

What condition should the surfaces of gloves and hands be in before setting up oxyfuel equipment?

Free of grease and oil Signup and view all the answers

Which of the following is true regarding the inspection of mixer assemblies?

Components should be inspected and replaced if wear or damage is present Signup and view all the answers

What is the purpose of reverse flow check valves in oxyfuel cutting and welding systems?

To prevent flame from traveling back to the oxygen cylinder. Signup and view all the answers

Which color is designated for oxygen hoses in oxyfuel cutting and welding?

Green Signup and view all the answers

What is a characteristic feature of the fuel gas connector nut?

It is threaded with a left-hand thread. Signup and view all the answers

What is a common requirement for the positive pressure mixer in oxyfuel systems?

Gases must be delivered at pressures greater than 14 kPa. Signup and view all the answers

How do flashback arrestors work when flames travel back through the system?

They extinguish the flame using a stainless steel filter. Signup and view all the answers

What type of thread is used for the oxygen hose connector to prevent incorrect connections?

Right-hand thread Signup and view all the answers

What are the two main purposes of mixers in oxyfuel systems?

To thoroughly mix oxygen and fuel gas and to reduce flashback risk. Signup and view all the answers

Which type of mixer is generally used with fuel gas pressures below 14 kPa?

Injector mixer Signup and view all the answers

What is the function of steel ferrules in the fuel gas hose connection?

To create a solid leak-tight connection. Signup and view all the answers

When a flashback arrestor is exposed to fire, what action does it take?

Stops the flow of gas. Signup and view all the answers

What is the purpose of purging the hoses in an oxyfuel outfit?

To remove contaminants and air from the hoses Signup and view all the answers

Which component does not require a sealing fibre washer for gas-tight connections?

Bull-nosed fittings Signup and view all the answers

What should be used to check for leaks in an oxyfuel outfit?

Approved leak detection solution Signup and view all the answers

What hazard is associated with blowing out the acetylene hose?

It can become explosive in certain concentrations Signup and view all the answers

Why should ammonia not be used on oxyfuel equipment?

It erodes brass components Signup and view all the answers

What type of threads do all oxygen connections have?

Right-hand threads Signup and view all the answers

Which item is NOT part of the oxyfuel outfit's components?

Leak detection fluid Signup and view all the answers

What is the first step in preparing the oxyfuel outfit?

Purge the hoses to remove contaminants Signup and view all the answers

What is the first step in the procedure for shutting down oxyfuel equipment?

Close the oxygen cylinder valve. Signup and view all the answers

Which of the following must be done after closing the oxygen cylinder valve?

Turn out the pressure adjusting screw of the oxygen regulator. Signup and view all the answers

What should you do if heating or cutting is stopped for an extended period?

Close the cylinder valves and bleed gas pressures. Signup and view all the answers

What is a backfire in oxyfuel equipment?

The flame backs up into the tip and re-establishes with a bang. Signup and view all the answers

Which of the following is NOT a malfunction associated with oxyfuel equipment?

Overheating Signup and view all the answers

Which action helps prevent flashbacks in oxyfuel equipment?

Frequent inspection of regulators. Signup and view all the answers

What must be done after the fuel gas cylinder valve is closed?

Bleed all pressure from the fuel gas torch valve. Signup and view all the answers

What should be done with the hoses after shutting down oxyfuel equipment?

Neatly coil them and place tips on the storage rack. Signup and view all the answers

What does the Bourdon tube in a regulator primarily do?

Actuate a needle indicator to show pressure Signup and view all the answers

What is the minimum bursting pressure that oxyfuel hoses must be designed to withstand?

2800 kPa Signup and view all the answers

Which material is NOT mentioned as part of the construction of oxyfuel hoses?

Polyester Signup and view all the answers

What is a common size of oxyfuel hoses used for most torches?

6.4 mm Signup and view all the answers

Why is it important to turn the adjusting screw of a regulator when it is out of service?

To apply spring pressure on the diaphragm Signup and view all the answers

What do the gauge faces on oxyfuel gas regulators indicate?

Remaining gas volume and pressure Signup and view all the answers

Which of the following is a requirement for oxyfuel hoses according to standards?

Must meet Canadian Standards Association specifications Signup and view all the answers

What is the primary function of oxyfuel hoses in welding and cutting?

Transmitting gases without leakage Signup and view all the answers

What is the recommended practice before lighting the torch?

Purge hoses by opening and closing valves one at a time. Signup and view all the answers

Why is it dangerous to light a torch using a mixture of oxygen and acetylene?

It can cause the flame to ignite with a loud pop. Signup and view all the answers

What happens if gas speed is set too low?

The flame burns inside the tip and backfires occur. Signup and view all the answers

What is the speed of flame propagation for properly mixed oxygen and acetylene?

5 m/s to 7.5 m/s Signup and view all the answers

Which factor determines the size of the gas stream leaving the torch tip?

The size of the tip orifice. Signup and view all the answers

How should you balance the working pressures for regulators?

Check and balance them as they can vary by as much as 30 kPa (5 psi). Signup and view all the answers

What should be avoided when lighting a torch?

Directing the flame toward flammable materials. Signup and view all the answers

What could happen if the gas speed is set too high?

The flame may leave the end of the tip. Signup and view all the answers

What is a critical part of checking regulators?

Balancing working pressures due to potential variations. Signup and view all the answers

Which method is NOT advisable for igniting a torch?

Lighting with matches. Signup and view all the answers

What condition can cause too little gas speed leading to backfires?

Low working pressures Signup and view all the answers

What happens during a burnback?

Combustion occurs steadily in the tip and mixer Signup and view all the answers

What is a potential cause of flashbacks?

Faulty manipulation of valves Signup and view all the answers

Which of the following is NOT a cause of backfires?

Low temperature flame Signup and view all the answers

What should you do quickly if burnback occurs?

Close both torch valves Signup and view all the answers

What differentiates burnbacks from flashbacks?

Burnbacks occur continuously without combustible material Signup and view all the answers

What immediate action should be taken to extinguish flames from a flashback?

Close the acetylene cylinder valve Signup and view all the answers

Which scenario can lead to an explosion causing a flashback?

Faulty seat connections Signup and view all the answers

Which of the following is a characteristic of flashbacks?

May cause severe equipment damage Signup and view all the answers

What aspect of hoses could lead to mixed gases and thus a flashback?

Unequal pressures Signup and view all the answers

Study Notes

Single-Stage Regulators

Single-stage regulators convert cylinder pressure to working pressure in one step.
Less precise control over delivery pressure is a disadvantage.

Two-Stage Regulators

Two-stage regulators transition cylinder pressure to working pressure in two steps:
- First, reduce cylinder pressure to an intermediate pressure of 1241 kPa to 2758 kPa (180 psi to 400 psi).
- Then, adjust from intermediate to working pressure.

Applications for Two-Stage Regulators

Commonly used in manifold systems, sensitive instrumentation, and experimental laboratory settings.

Regulator Malfunctions and Creep

Creep occurs when high-pressure side valve fails, causing gas leaks, which can raise pressure above normal limits.
Symptoms of creep include:
- Leaks from diaphragm failures at the first and second stage.
- Relief valve leaks due to first stage malfunctions.
Remote repair solutions involve checking for ruptured diaphragms and cleaning valve components.

Hose Maintenance

Test hoses for leaks using immersion in water under pressure.
Avoid repairing hoses with tape; instead, cut and splice with approved fittings.
Do not use copper tubing for acetylene hoses due to explosive reactions.

Flame Types in Oxyacetylene

Carbonizing Flame: Rich in acetylene, lower temperature, produces excess carbon.
Neutral Flame: Balanced oxygen and acetylene; temperature reaches 3090°C (5600°F).
Oxidizing Flame: Rich in oxygen, can reach 3470°C (6300°F).

Oxyfuel Outfit Setup

Purge hoses to remove contaminants; perform with caution using acetylene.
Ensure secure cylinder connections and check for leaks using approved leak detection solutions.

Types of Fittings

Flat-faced fittings require a fibre washer; bull-nosed fittings do not.
Oxygen fittings have right-hand threads, while most fuel gases use left-hand threads.

Leak Detection Fluids

Avoid petroleum-based detergents for detecting leaks on oxygen equipment.
Use non-toxic leak detection fluids specifically designed for oxyfuel applications.

Torch and Mixer Maintenance

Regular inspection and replacement of O-rings, seals, and gaskets are crucial for safety.
Tips should be cleaned, stored properly, and not misused to maintain functionality.

Emergency Shutdown Procedures

If a flashback occurs, initiate emergency shutdown by closing both cylinder valves and extinguishing flames.

Backfire, Burnback, and Flashback Causes

Backfires are due to low gas speeds, dirty tips, or obstruction.
Burnbacks involve combustion in the tip and mixer, often caused by hot tips.
Flashbacks are the result of gas mixing in hoses due to unequal pressures or improper valve manipulation.

Oxyfuel Hoses

Fuel gas hoses are red; oxygen hoses are green.
Construction involves materials that are resistant to heat, wear, and various liquids.
Standard sizes vary from 5mm to 10mm, with 6.4mm being the most common for general use.
Hoses must meet CSA specifications and withstand a minimum bursting pressure of 2800 kPa (400 psi).### Regulator Gauge Faces
Oxyfuel gas regulator gauges display pressure in metric (kPa) and imperial (psi) units.
Oxygen cylinder pressure gauges may indicate remaining gas volume.

Storing Out-of-Service Regulators

For regulators inactive for weeks, adjust the screw to apply spring pressure on the diaphragm; this keeps the valve stem off the seat and prevents corrosion.
Before reusing, back off the adjusting screw before opening the source pressure.

Lighting the Torch

Purge hoses by sequentially opening and closing torch valves to remove air or explosive mixtures, especially when multiple users are present.
Use a proper spark igniter to light the torch; avoid matches or cigarette lighters due to burn risks.
Do not ignite torches with a mix of oxygen and acetylene, as this can cause dangerous, explosive ignitions.
A noisy, smoky flame often indicates improper acetylene flow; open the acetylene valve more fully to improve combustion and air quality.

Gas Speed and Speed of Flame Propagation

Understanding gas speed and flame propagation is crucial to prevent backfires and ensure proper torch function.

Gas Speed

Refers to the rate at which mixed gases exit the torch tip, measured in linear feet per second.
Determined by tip orifice size; visually analogous to a stream of raw gasoline from an unlit torch.

Speed of Flame Propagation

Describes how fast a flame moves in a stream of premixed gases.
Properly mixed oxygen and acetylene has a flame propagation speed of 5 m/s to 7.5 m/s (17 ft/s to 25 ft/s).
Lower gas speeds (below 5 m/s) can cause flames to burn inside the torch, leading to backfires.
Excessive gas speeds (above 7.5 m/s) risk the flame leaving the tip, especially when heating edges and corners due to low resistance.

Checking and Balancing Pressures for Heating Tips

Regulators may show a variance of up to 30 kPa (5 psi) in working pressure accuracy; regular checks and balances are necessary.
Industrial regulators provide a rough pressure estimate suitable for cutting but require maximum control for heating operations.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on single-stage regulators and their components. This quiz covers the functionality, advantages, and disadvantages of using single-stage regulators in pressure control. Be ready to identify different parts and understand their roles in the regulation process.