Milnor Knowledge:
updated 09/21/18
This is a compilation of interesting info that helps calculate answers to questions you may have when looking at performance of a Laundry.
Compiled by Gary Lazarre
Handy conversions :
Steam sparger - 1/2" sparger orifice flows 1,100 lbs of condensate per hour at about 100 PSI. (This varies by pressure)
34.5 lbs steam = 1 boiler HP (rule of thumb for Boiler guy)
G-force = diameter(inches) * RPM² / 70471
Air conditioner - 1 Ton = 12,000 BTU
Flow/ pressure - flow varies as a square root of the pressure.
Gas / Moisture - 11 gal of water produced per 1,000 ft³ of natural gas burned.
Natural = 1,030 BTU/ft³
Propane = 2,515 BTU/ft³
Gasoline = 125,000 BTU/gal
#2 fuel oil= 138,700 BTU/gal
#6 fuel oil = 149,700 BTU/gal
Head (water) - 27.7 inches water = 1 PSI
1 PSI = 0.0689 Bar
1 Bar = 14.5038 PSI
1 PSI = 2.03602" Hg
Volume Conversions
1 ft³ water = 7.48 gallons
1 ft³ water = 62.43 lbs
1 gal water= 8.33 lbs
Evaporation credit - if you can get one from the water company...
Water evaporated in a dryer or ironer - given 50% moisture retention, is .0599 gallons per pound. Given - 120 pounds goods at 50% moisture yields 60 pounds water/8.33 pounds /gallon=7.2 gallons and .059 gallons per pound.
Motor hp - 1 motor hp = 746 watts. 1kwh = 3413 btu
1 boiler hp = 9803 kw
1 boiler hp = evap rate 34.5 pounds of water per hour when feed water is 212º F and absolute pressure is 14.7 psi
BTU - heat required for 1 pound of water to raise 1 deg at atmospheric pressure.
Therm - 100000 BTU's
Boiler hp = 33,500 BTU's per hour.
Extraction Efficiency
Efficiency is raised by 5 points of moisture if the temperature is raised from 80 degrees to 120 degrees and 300 g's applied.
L/kg to Gal/lb.
3.83 liters/gal
2.2046 lb/kilo
3.83 * 2.2046 = 8.4436 L/kg is equivalent to 1 Gal/lb.
8.4436 liters per kilo = 1 gallon per pound.
Steam "consumption" at the boiler (Washer-Extractor)
Gal/hour(to be heated) x 8.33(lbs/gal) x delta T( hot water temp - incoming water temp) = BTU per hour, then divide by boiler efficiency( MAX 80% ) = true BTU per hour at boiler. BTU divided by 970 BTU's per lb of steam divided by 2.2 = kg per hour of steam per hour.
Use 3.5 gal of water per hour per pound of machine capacity = gal per hour (hot and cold combined)(figure 70% hot water).
Thus the 3022X8J(55 lb capacity) would require 65 kg of steam per hour "based on a hundred degree rise". The 42032X8J(165lb capacity) would require 197 kg of steam per hour "based on a hundred degree rise".
Natural gas to therms:
Is there a direct conversion from therms to cubic feet of natural gas?
There is - based on pressure, but I don't have it handy. Either way, a therm is 100,000 BTU.
The average heat value of natural gas is 1000 BTU/ft³. A BTU (British Thermal Unit) is enough heat to heat one pound of water one degree (F). Natural gas is sold to the customer in units of 100ft³ (therm) or in a unit called MCF. A therm represents approx. 100,000 BTU of heating power, enough to heat a normal home for about 2 hours during colder weather.
MCF is ten therms, or 1 million BTU's. Prices vary, from as low as $.80 to as high as $1.00+ per therm. (in year 2000 approx) $2.61 in Honolulu in 2017.
Natural Gas is delivered to the customer at a very low pressure, usually less than 1/2 PSI. The pressure is expressed in Water Column (WC), where 28" WC = 1 PSI.
Filling a CBW module...how many gallons?
76039 CBW Module
| Water Level | Gallons of Water |
|---|
| 10" | 73 | | 12.5" | 87.23 |
|
|
This data came from 9248 CBW observations – conventional flow.
- Water flow for 20 seconds of chem flush at 53 psi is 1.25 gallons. Pretty significant to water flow when there are 4 mods injecting water
- CBW 9248 fillage –
- Bottom of weir box is a 4” level in the basket of the CBW.
- Level switch with 1” gap between the clips creates 3” dead band on level switch.
- After the flow stops closed and we were at fixed weir heights we had 17.5” water level in the CBW wash zone.
- An empty mod refilled to 11” showed 126 gallons of water used.
- With goods in the module and then dumped, 69 gallons were used to refill to a 9 level.
- Predict 10 gallons per inch in an empty module at 10” level.
- 10” level showed 115 gallons from empty fill.
- 9” level showed 105 gallons from empty fill.
- All values include flow tube and back of weir in next module.
- Total free water with goods rotating in an established counter flow - 69 gallons plus 80 gallons more (7 inches more) or 150 gallons in a module of total water to dose.
The absorbed water is 2.95 pounds per pound of goods.
81 gallons in 225 pounds of goods for 100% cotton.
47 gallons for 50/50 poly cotton or 1.71 pounds per pound.
Total water to dose is 150 gallons plus 81 gallons or 231 gallons.
Calculating water levels and corresponding volumes for the 76 inch CBW modules with examples
CBW Water Levels and corresponding Volumes
Total Gallons (Cylinder) = [(3.14159)/4] X (Dia.)^2] X [Length]
To determine the total gallons for a specific water level - Multiply the total Volume of the cylinder times the Depth Factor for what water level.
Depth Gallons (without sump)
Level(in) H/D Factor 76028 76032 76039
7.5 0.0987 0.05108 28.09 32.10 39.12
8.0 0.1053 0.05625 30.93 35.40 43.08
8.5 0.1118 0.06144 33.78 38.60 47.06
9.0 0.1184 0.06670 36.68 41.90 51.09
9.5 0.1250 0.07226 39.73 45.40 55.34
10.0 0.1316 0.07792 42.85 48.90 59.68
10.5 0.1382 0.08357 45.95 52.50 64.01
11.0 0.1447 0.08937 49.14 56.20 68.45
11.5 0.1513 0.09535 52.43 59.90 73.03
12.0 0.1579 0.10133 55.72 63.70 77.61
12.5 0.1645 0.10755 59.14 67.60 82.37
To determine the total gallons per module with the sump can be approximated by adding five gallons to the above totals.
76039 G3 Plus and PBW weir settings, etc.
The top of the weir box is equivalent to a level of 21” in the shell . The top of the divider is at 16.5” in the shell. The basket level is 1” less than the water level in the shell.
The conclusion is that any time the water in the weir box is closer than 5” to the top then you will be flowing over the divider. Put a tape measure in the box to see the results.
In a PBW we would normally take out the weir plates to help flow through a zone due to high water levels being forced by high flow rates. But, in a PBW with drain valves if you leave the plates out then the module can partially drain the previous module to the height of the fixed weir at 6”. So, weir plates are needed in a machine with drain valves to limit the reduced level when draining adjacent modules. We recommend 8”, not cascading, but you can play with this to the limits of the discussion above. You never want a condition where the water flows over the divider.
Big bolt tightening using a slam or slugging wrench
This technique uses angular displacement to torque the bolt adequately.
- Tighten by “hand”. Use the 1-11/16” wrench and pull hard. Use an 18” cheater bar if you need it.
- Mark the center of one of the flats on each bolt and also the washer under the bolt head and goose neck flange to identify the current position of the bolt head onto the washer.
- Use the slam wrench to turn each bolt another 1-½ flats. (1/4 turn)
If you went to “1-2/3 flats” it would not hurt anything. The bolt has plenty headroom above this before you reach yield strength.
