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Table of Contents

1. Help with this web site

2. Glossary / What is....

3. Studio Sizing

4. Safety System Requirements

HELP WITH THIS WEB SITE

Problem: You cant view the Flash site, only the HTML, simple, text based site.
Solution: You must have the Macromedia Flash 5 player or later installed. Click here to download Flash 6.

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Solution: Click on the button for "overview . news", wait for this section to appear. Then click the button for the section you want and let that appear. If this still doesnt load, refresh your browser and try to view your desired section again. If this still doesnt work, email the webmaster with your operating system info and browser type and switch to the text based site temporarily.

Problem: This site is great but when I click "view details" for a certain piece of equipment, it doesn't give me any details, what gives?
Solution: If no window pops up when you click "view details", you probably dont have Java enabled on your browser. Consult the help section in your browser. Old versions of Netscape may encounter this problem. Please upgarade to the latest version of your browser (Internet Explorer recommended). If this still doesnt work, email the webmaster with your operating system info and browser type and switch to the text based site temporarily.

GLOSSARY / WHAT IS....

"w.c. or inches of Water Column?

The vertical displacement of a column of water due to pressure acting against the water head. 27.7" w.c. is equal to one psi.

3 phase?

No matter what it is that spins the generator, all commercial electrical generators of any size generate what is called 3-phase AC power. To understand 3-phase AC power it is helpful to understand single-phase power first. Single-phase power is what you have in your house. You generally talk about household electrical service as single-phase 120 volt AC service. If you use an oscilloscope and look at the power found at a normal wall-plate outlet in your house, what you will find is that the power at the wall plate looks like a sine wave, and that wave oscillates between -170 volts and 170 volts (the peaks are indeed at 170 volts; it is the average (rms) voltage that is 120 volts). The rate of oscillation for the sine wave is 60 cycles per second. Oscillating power like this is generally referred to as AC, or Alternating Current. The alternative to AC is DC, or Direct Current. Batteries produce DC: a steady stream of electrons flow in one direction only from the negative to the positive terminal of the battery.

AC has at least three advantages over DC in a power distribution grid:

1. Large electrical generators happen to generate AC naturally, so conversion to DC would involve an extra step.
2. Transformers must have alternating current to operate, and we will see that the power distribution grid depends on transformers.
3. It is easy to convert AC to DC but expensive to convert DC to AC, so if you were going to pick one or the other AC would be the better choice of the two.

There is nothing special or magical about 3-phase power. It is simply three single phases synchronized and offset by 120 degrees.

Why three phases? Why not one or two or four? One big advantage that 3-phase power has over 1-phase or 2-phase power is the fact that, at any given moment, one of the three phases is nearing a peak. In 1-phase and 2-phase power there are 120 moments per second when the sine wave(s) cross zero volts. High-power 3-phase motors (used in industrial applications) and things such as 3-phase welding equipment therefore have even power output. Four phases would not significantly improve things but would add a fourth wire, so 3-phase is the natural settling point.

And what about this word "ground," as mentioned above? The power company essentially uses the earth as one of the wires in the power system. The earth is a pretty good conductor and it is huge, so it makes a good return path for electrons. [Car manufacturers do something similar; they use the metal body of the car as one of the wires in the car's electrical system and attach the negative pole of the battery to the car's body.] "Ground" in the power distribution grid is literally "the ground" all around you when you are walking outside. It is the dirt, rocks, groundwater, etc., of the earth.

The 3-phase power leaves the generator and enters a transmission substation at the power plant. This substation uses large transformers to convert the generator's voltage (which is at the thousands of volts level) up to extremely high voltages for long-distance transmission on the transmission grid.

(read more about this at How Stuff Works)     (Back to Top)

Btu

The quantity of heat required to raise one pound of water one degree Fahrenheit.

Combustion Air

Air supplied to a burner for the combustion reaction. It includes all the required air regardless if premixed with the fuel before ignition or enters through the flame envelope.  (What is volume combustion?)

Excess Air 

That portion of the air which is mixed with the fuel and does not react. It tends to lower the temperature of the combustion products.

Lean Mixture

A fuel-air mixture which contains more air than is necessary to completely burn the fuel portion.

Reducing Atmosphere 

Products of combustion which result due to a deficiency of air in the air-fuel mixture. Sometimes done intentionally to prevent oxidation of process materials.  There is an available reduction atmosphere pedal for Wet Dog Glass glory holes.  (Go to glory holes page)

Rich Mixture 

A Fuel-air mixture which contains an excess of fuel with respect to the air needed for complete combustion.

Stoichiometric Mixture

A mixture of fuel and air whose proportions are determined by an exactly balanced chemical equation of the reaction.

Turndown 

Ratio of maximum to minimum firing rates.

Venturi 

A flow tube having a smooth converging section followed by a smooth diverging section. Used in gas engineering to convert high velocity pressure to static pressure with minimum total pressure loss. (Go to Venturi page)

Volume combustion

The space required to complete the combustion reaction. Can also refer to the ratio of heat input to combustion chamber volume.

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STUDIO SIZING

How do I know what size glory hole to buy?

Measure the pieces you want to make, add a few inches so you don't have to squeeze your way out of the hole every time.  Let us know your available gas type and pressure.  Many shops have a small assistant's hole and one gaffer hole. (Go to glory holes page)

How do I know what size annealer to buy?

For annealing ovens, it is ideal to only have to use one kiln per day for blown glass, unless you make tons of glass.  You can measure your glass and find out what size annealer you'll need to hold a day's amount of glass. Front loaders make it more easy to use shelves, thereby getting more glass into the oven.  If your work will require long annealing cycles, figure out how many days it will take to anneal a day's work.  You'll need that many annealers plus one.  Let us know your available voltage and amperage. 

How do I know what size furnace to buy?

Well, first we will need to know how much glass you will use per week.  An easy way is to 1) Weigh one of your typical pieces of glass 2)  Multiply that weight by the number of pieces you plan to make per day. 3)  Multiply that number by 5 days.  4)  You can add a 25% margin for the glass at the bottom of the pot plus moil crack offs and punties.  The idea is that you want to charge once a week.  If you have to charge more frequently, you may spend more on gas than necessary, and less frequently tends to give lower glass quality. 

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SAFETY SYSTEMS & COMBUSTION

Understanding Glory Hole Combustion Article (with illustrations and product descriptions)