Lets talk about Pencil Jets
Water flow from Pencil Jets is a personal preference and depends a lot on how much water volume and pressure you have available.
Most water-fed poles pencil jets are rather small about 5/64in or 2mm in size.
The small sizes allows for water conservation and is ideal systems that produce a small amounts of water flow like back packs and tap water pressure RO/DI.
This is important in the UK where they carry their water.
In the US where water is easily accessible and made on demand many window cleaners elect to use larger pencil jets for a faster rinse with less splash-back.
Click to Enlarge
A larger orifice slows the water down and allows a larger rinse pattern and allows you to clean more glass per hour. Larger Pencil jets are especially useful on hydrophobic glass.
Here we are using two different size pencil jets for the nLite brushes from Unger.
In the illustration above the left picture Pencil Jet is 5/64inch and the right 1/8in, notice the rinse area is larger for the 1/8in jet (right) on this hydrophobic glass.
Both jets are operating at the same distance and same pressure.
The 1/8in jets will make the rinsing easier.
Recap:
- Smaller jets are great for those with back pack (small pump) sprayers or low water pressure and those that need to or want to conserve water.
- Larger Jets are slow the water down and allow and easier and quicker rinse.
The water consumption difference in jets sizes small to medium is very small, maybe 0.2 gallon per minute, that represents a lot when you only have 4 gallons available.
But is not very noticeable to a person with a good RO/DI unit
This is a table of Pencil Jets sizes as we know them.
|
Drill Size |
|||
|
Millimeter |
Decimal Inch |
Fractional Inch |
|
|
UK Gardiner |
1.8 |
0.070 |
|
|
Euro Small |
2 |
0.078 |
5/64 |
|
USA Small |
2.3 |
0.094 |
3/32 |
|
USA Medium |
3.2 |
0.125 |
1/8 |
|
USA Large |
4 |
0.156 |
5/32 |
|
XL (Tucker) |
5.1 |
0.203 |
13/64 |
Pencil jets have been easy to change in some manufactures brushes.
(Tucker and nLite) For others changing to a medium size jet is a simple as running a the right size drill bit through the pencil jets in the brush they already have. If you are interested the table above will help you decide the size for you. I suggest USA Medium as a good start, it has proven to be a favorite of many of US window cleaners
Click here to check out the jets for Unger’s newest waterfed pole, the nLite.
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