How to Make a Pentair Nozzle

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How to Make a Pentair Nozzle

Post  pmolsen on Fri Nov 20, 2009 12:07 am

I have decided to build a nozzle based on the Pentair design described at http://laminar.forumotion.com/laminar-nozzle-talk-and-pictures-f1/pentair-flow-jet-t38.htm In other words a nozzle using plastic screens with big holes then mesh screens but no straws or filter sponge.

The other big difference between the Pentair nozzle and the ones people on the forum seem to be making is the size. It appears to be only about 4-5" in diameter and 7-8" long. I am assuming that it can output a reasonable stream so I figure that scaling it up to a 6" nozzle should give me the 3m x 1.5m high (10' x 5') stream that I want for my indoor fountain.

I intend to document the construction process, both for my own benefit later as well as for others. I have no idea at this stage how well it is going to work. All sizes are in mm. (When are you US and UK guys going to get with the times and convert to metric? Based on the Australian experience it takes about 30 years to fully convert so you had better get started.)

I am in Sydney and bought all the materials from the places indicated, apart from the nozzle ring.

Materials:

1. Brass nozzle ring from Mad-laboratory John (coming in the mail). I figured it would cost a lot more in time and effort to make one than the $10 he charges. Thanks John.

2. Two 150mm sewer pipe couplings with screw ends from Ace Gutters, Boundary Rd Peakhurst. $16 each. Bunnings sell for $20.

3. Two 150mm screw end caps with rubber seals for the top and bottom ends, from Ace Gutters. $17 each. Bunnings sell for $16.

4. A piece of 150mm sewer pipe about 200mm long. I got it from friend, otherwise Ace Gutters. But it is expensive for a 6m length. Bunnings sell 1m lengths for $23.

5. A 25mm plastic pressure-pipe screw adaptor for the inlet connector, from Ace Gutters or Bunnings. $2

6. A 25mm x 20mm brass "nut and tail" tap fitting for connecting a 20mm garden hose to the 25mm inlet for testing and maybe to connect the pump also. From Ace Gutters. $7

7. Stainless steel mesh pieces with holes-per-inch sizes of 10, 16, 40 and 72. $116 for 4 pieces of mesh.

I bought a 10-hole-per-inch offcut from Sefar Filtering, 19-21 Huntingwood Dr Huntingwood. (10-23 which is 10 holes per inch, 23 gauge wire). They had the best range and display but were more expensive. I bought the other three pieces from Star Screens, 5 Kenoma Place Arndell Park.

The mesh was expensive due to the need to buy a lot more than I needed. Kitchen sieves like these with varying hole sizes might be an alternative: http://www.kitchendiscounts.com.au/buy/metaltex-20cm-stainless-steel-strainer/2019 providing they are stiff enough. The mesh I bought has thicker wire than sieves use so it holds its shape when pushed into the nozzle.

8. A sheet of 4.5mm PVC for the first two screens. From Plastix, cnr Princes Hwy and Tantallon Av Arncliffe. $15

9. An offcut of 16mm perspex (plexiglass) rod from Plastix. $5

10. A length of 20mm electrical conduit (grey) from John R Turk. $3

11. A 20mm electrical screw connector from John R Turk. $1

12. Clear electrical PVC pipe glue (not blue plumbing pipe glue) from John R Turk. Only because the blue looks messy. $3

Plan of Attack:

My intention is to build the nozzle without any light tube to make sure it will produce a good laminar flow first. I will then add the light tube later. That way I limit the things that can affect the quality of the stream.

The light tube I will be using will be 20mm electrical conduit so I have to plan the size and location of the holes in the bottom screens so that I can drill the centre hole later. If you drill a big hole in the middle then it is difficult to centre the 20mm hole saw later. Hence the small centre hole. Also the next holes have to allow for the future 20mm hole.

Making the cutter will be last.

Inlet Construction:

- Take the 25mm plastic screw adaptor (5. above) and cut across the socket end at about 45 degrees on a band saw or with a hacksaw.



- Round out the cut edge on a 6" bench grinder so it mates neatly with the side of one of the sewer pipe couplings (2) above.



- Use a dremel tool with a round grinding stone to smooth off the sharp step in the middle of the fitting where it changes size, to reduce the creation of turbulence there. See first photo above.

- Screw the end cap on a 150mm coupling piece. This is what the coupling and end cap looks like.









- Place the rounded out adaptor against the side of the coupling so it just clears the cap and trace with a pencil around the inside of the adaptor hole to mark for the cutout hole in the coupling.

- Use a 20mm hole saw and drill a tangential hole through the coupling (as tangential as you can get it). I used a drill press to avoid it skipping off the angled surface. Finish it with a round file, testing regularly with the adaptor to ensure that the two holes are the exact same size.



- Remove the end cap so you don't accidentally glue it on.

- Glue the adaptor over the coupling hole with clear PVC pipe glue. Use plenty of glue. Smooth out the join between the adaptor and coupling with glue. Ensure they are accurately aligned.



This is the hose adaptor that attaches to the above inlet:




End Caps:

- The end caps I got from Ace Gutters are not smooth on the inside. They have a series of strengthening ribs. You can vaguely see the remains of them in the photo above.

- Use a hammer and chisel to remove the ribs. Be careful not to cut gouges in the surface beside the ribs on the top cap. If you do, refill them with pipe glue. The bottom cap does not matter because a circle of anti-jitter foam will be glued inside that cap. See further down.

- The ones that Bunnings sell do not have those ribs so they are better in that respect. The ridge around the edge that holds in the rubber O-ring is bigger and more square on the Bunnings ones however so that may cause turbulance in the corner. The Ace Gutters one is chamfered as can be seen in the photo above which is better. It doesn't matter with the bottom cap but it may with the top cap.


Last edited by pmolsen on Sun Nov 22, 2009 12:27 am; edited 7 times in total

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Re: How to Make a Pentair Nozzle

Post  pmolsen on Fri Nov 20, 2009 1:12 am

Plastic Screen Construction:

Above the inlet there are two plastic screens, 35mm (1-3/8") apart. Screen 1 has 10mm (3/8") holes. Screen 2 has 4mm (5/32") holes. The holes must be evenly spaced, not just randomly positioned. The following assumes you don't have a laser cutter.

- Mark two circles on the 4.5mm thick PVC sheet by tracing around the outside of the 150mm pipe. Make sure the end of the pipe is cut perfectly square. See below. Alternatively measure the pipe accurately then draw the circle with a compass.

- As I don't have a lathe or other suitable machine I cut out the circles with a band saw then ground them accurately on a bench grinder. Test regularly for size and accuracy by trying to insert it inside the coupling.

- If you traced around a pipe you need to find the centre of each disc. Place a sheet of paper over the circle with a corner touching the edge. Mark the two places where the sides of the sheet cross the edges of the disc. Draw a diameter line across the disc between those two points. Move the paper around the circle so the point is on one end of the diameter line and repeat. Draw a second diameter line. Where the lines cross is the centre. Tap a mark with a centre punch or nail.

- Rub out one of the lines leaving only one line.

Screen 1: (10mm holes)

- Draw a series of parallel lines above and below the middle line 18mm (5/8") apart across the entire circle.

- Using a protractor draw a line through the centre point at an angle of 60 degrees to the original centre line.

- Now draw a series of parallel lines above and below that angled line 18mm (5/8") apart across the entire circle.

- At every point where any two lines cross punch a dent with a centre punch or nail. Do NOT punch any marks within 10mm (3/8") of the edge of the circle.

- I marked out the lines on a piece of paper then taped it to the plastic disc and punched the holes.

- In the photos there are a serial of diagonal spokes and circles drawn on the paper. I tried them initially but the parallel line method is better. The two will coincide for some of the holes as you can see.



Screen 2: (4mm holes)

- Mark out the same as above except the lines are 7mm (1/4") apart.

- Do not punch any points within 7mm (1/4") of the edge of the circle.

- I drew the lines directly on the plastic for better accuracy with the small holes.



Drilling:

- Check that the table of your drill press is perfectly level and at right angles to the drill bit. I failed to check and all my holes were angled slightly. BAD!

- Use a new or very sharp drill bit, NOT an old worn one. It is important that the holes be sharp and clean.

-NOTE: DO NOT drill a 10mm hole in the middle if you intend to drill a 20mm hole for a light tube later. If you do it will be impossible to properly locate the 20mm core hole bit. Instead drill a smaller hole the same size as the smaller drill bit that runs down the middle of a core hole bit.

- Using a drill press drill 10mm holes at every marked position. Use fastest drill speed available. Jiggle the drill up and down so it cuts out small shavings. If you just drill straight through in one go the shavings get twisted around the drill bit and you have to keep stopping the drill and removing them.

- As the drill gets to the bottom of the hole hold the plastic firmly or it will jump up the drill bit and make an angled hole. BAD!

- You can see that I also drilled small holes near the edge at the places where a big hole did not fit. I am not sure if that was a good idea or not. The idea was to try to allow an equal amount of water through across the entire disc but those small holes might "squirt" the water through faster and reduce rather than improve the laminar flow.







- After drilling the holes there will be a small lip around the top of each hole. Get a bigger drill bit and use it to chamfer the hole very slightly to remove the lip. Hold the drill bit in your fingers and spin it. DO NOT put the drill bit in the drill press. It will cut too deep a chamfer.

- After doing that there will still be some plastic hairs sticking into the holes. Take a sharp drill bit that is one size smaller than the hole. Push it up and down through the holes like a file. The sharp edges will cut off the small hairs.

- The whole process to make each plastic screen took about 2 hours per screen.


Last edited by pmolsen on Fri Nov 20, 2009 4:40 pm; edited 1 time in total

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Re: How to Make a Pentair Nozzle

Post  pmolsen on Fri Nov 20, 2009 2:37 am

Plastic Screen Installation:

- Cut a 30mm wide ring from the end of the 150mm pipe. To draw an accurate line around the pipe take a large sheet of thin cardboard or paper (eg. newspaper) and wrap it around the pipe. Align the edges of the paper and draw a line around the edge of the paper.

- If cutting by hand with a saw use a wide timber saw not a hacksaw. It cuts straighter. Do not cut straight down through the pipe. Rotate the pipe as you cut and only cut just through the pipe wall. That way it is easier to keep the cut on the line.

- Smooth both ends with a file or by rubbing them on some sandpaper placed on a smooth surface.

- Place the pipe coupling down with the inlet nozzle near the bottom.

- Smear PVC glue around the inside of the coupling on the top edge of the dividing ring that runs around the centre of the coupling and 25mm up the sides.

- Do not put glue on the ring. Push the ring down over the glue and tight against the middle ring and glue. Use a hammer and piece of timber to tap it down tightly. Wipe off excess glue from the joint. This photo shows the coupling turned up the other way.



- Smear glue around the top edge of the inserted 30mm pipe ring and up the sides 3mm. Push the disc with the SMALL holes down onto the glue. The side that you drilled from should face upwards. The other side will have sharper, cleaner hole edges. Clean excess glue from both sides and use a nail to clean out any holes with glue in them.



- Turn coupling up the other way so the inlet adaptor is near the top.

- Place a small amount of silicone in two opposite places on the middle ring and push the screen with the BIG holes into place. We are not gluing it in fully at this stage in case we have to modify the design later. The water pressure will keep it in place. The side that you drilled from should face away from you, towards the small screen. That means the clean, sharp edges of the holes face the inlet.



- Cut another piece of pipe 122mm long. It will join the two couplings together to form the full nozzle body. The length equals the distance from the second screen to the top of the coupling, PLUS the length from the edge of the upper coupling to the separator ring in the middle of it. With mine it worked out to 120mm. Add a couple of mm for safety to make sure the two halves can be fully pushed together onto the joiner.

- Smear glue on the remaining area of the inside of the coupling above the small-hole screen and on a similar length of the 122mm pipe and glue the pipe in. Tap it down firmly. Clean off any excess glue and clean out any holes that get glue in them.



That protruding piece of pipe will get pushed into the second coupling that will contain the wire mesh screens. It should be tight enough to stay together without any glue. Small stainless screws can be used to keep the two halves together if necessary but they must not penetrate to the inside. We do not want to glue it all together otherwise we cannot install the lighting tube or pull it apart to clean it.


Last edited by pmolsen on Fri Nov 20, 2009 4:48 pm; edited 5 times in total

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Re: How to Make a Pentair Nozzle

Post  pmolsen on Fri Nov 20, 2009 4:23 am

Wire Mesh Screens:

Here are some photos of the stainless steel mesh I bought. I've included a ruler to better show the sizes.

First is 10-23 which means 10 holes per inch, 23 gauge wire.



Second is 16-24.



Third is 40- something. Not sure of the thickness. The second photo shows the code.





The fourth screen is 72 holes per inch and very fine. It is not a standard weave like the others but is called 12/72 Hollander weave. A standard weave 72-hole per inch screen uses very thin wire and is much too soft to hold its shape. It is soft like nylon flyscreen. This mesh has thick straight wire running in one direction, with very fine wire woven in the other direction. See http://www.metalmesh.com.au/cfm/index.cfm?newLocation=cfm/prodDetail.cfm%3FcategId%3D3%26rangeId%3D1%26prodId%3D5

I am a bit worried about using it though. Because the holes are not square it may not produce an even laminar flow. I might have to remove it and add 2 x 40-mesh in its place. Or just use the 3 screens.



- NOTE that you cannot cut circular disc of mesh then push it into the nozzle if you want a concave finish to the mesh like the Pentair screens. The mesh bends more in some directions than others. You have to make them as explained below.

- There is also no point in cutting out the mesh into a standard cone shape. (Cut a circle, cut out a wedge then bring the two sides of the wedge together.) That makes a nice strong perfect cone but where you join the two edges of the wedge it will create turbulance in the laminar flow. It has to be made from one piece like you see in the Pentair photos in the separate posting.

For the record here is the real Pentair mesh screen, courtesy of PBRACER. You can see the end of the light tube poking through.



Repeat the following for each of the four screens.

- Cut out a square of mesh around 220mm x 220mm. Push down into the top of the second nozzle from the screw thread end to bend it into a rounded shape. If you have a big hard round ball it will help. I used the rounded part of a 90 degree 100mm sewer pipe elbow.



- The coarse 10-hole-per-inch mesh is relatively easy to bend into shape. The thinner ones with the finer holes tend to buckle when pushed into the hole. Keep smoothing out the wrinkles to make a smooth concave curve. The correct shape of the curve for the best result is unknown. Presumably it is one where all points of the curve are equidistant from the exit hole.

- When you have the desired shape hold it there and draw a circle on the mesh around the edge of the hole. When released the shape is a rounded square.



- Cut out the shape with sharp tinsnips.






- With the coarse mesh I cut the corners slightly wider, pulled out the edge wires and bent over the points so as to prevent the edges from falling apart. Note how I bent them so that the bent pieces lie beside the other wire. I then hammered them down gently. That way they do not increase the thickness of the edge significantly in case we decide to use separator rings later. (See comment below).





- Push the mesh screens down into the second coupling from the end with the screw thread. (Not the coupling with the plastic screens and the inlet. Push them into the second, unused coupling.) Push the coarse mesh right down to the ridge in the middle of the coupling and the others progressively less far. The fourth one is right up near the top, just enough so it sticks in place.

- At this stage I just pushed them in with no separator rings between them. They are stiff and stick in very tight. I will try that first and see how well it works. If the mesh screens come loose or there is a problem with the laminar flow I will try inserting separator rings between them.

- Remember also that we will be removing them later and cutting a 20mm hole in the centre of each one to insert the lighting tube. They will be a tight fit on that as well which will hold them in place firmly as well.





Last edited by pmolsen on Sat Nov 21, 2009 12:55 pm; edited 10 times in total

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Re: How to Make a Pentair Nozzle

Post  covewi on Fri Nov 20, 2009 3:58 pm

Great Job.

On your next to the last photo - is the coarse screen above the small hole pvc plate?

So from the bottom of the tube it goes like this -

screw cap - large hole pvc plate - spacer - small hole pvc - coarse screen - then smaller and smaller screen.

Correct so far?

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Re: How to Make a Pentair Nozzle

Post  pmolsen on Fri Nov 20, 2009 4:13 pm

Sort of. There are two pipe couplings. The inlet adaptor and two plastic screens are installed in the lower coupling. The mesh screens are installed in the top coupling. The two couplings are joined together with a length of pipe. The pipe is glued into the bottom coupling. It has to be because the lower screen takes up 35mm of the coupling hole leaving only the top 30mm or so for the pipe. Those plumbing fittings are slightly tapered inside so the pipe only sticks tight when it is pushed fully inside. If it is not glued in then it is loose and not watertight. The upper coupling has nothing inside the bottom so the pipe will push up fullly and jam tight.

Here is the full assembly. The 30mm ring is inside the right hand end of the left-hand coupling. The wire mesh screens are inside the right-hand end of the right-hand coupling.

The order from left to right is:

End cap - coarse screen - coupling with inlet - 30mm ring - fine screen - 122mm pipe piece - coupling - coarse mesh, medium mesh, fine mesh, very fine mesh, end cap with 1/2" brass hole








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Re: How to Make a Pentair Nozzle

Post  pmolsen on Sat Nov 21, 2009 12:55 am

Light Tube:

- Cut a piece of electrical conduit so it is rougly 40mm shorter than the finished nozzle length. The end of it has to protrude 5mm through the hole in the final mesh screen.

- Cut a 20mm long piece of 16mm perspex rod and polish both ends. (Get the supplier to do it for you.)

- Smear some silcone around the perspex piece and hammer it into the end of the 20mm conduit. It is a perfect fit.

- Glue the threaded adaptor to the other end of the conduit.

- Drill a 20mm hole in the middle of the bottom cap.

- Insert the 20mm screw adaptor through the cap from the inside and fasten it tightly with the nut.

- Push 3mm optic fibre cable up inside the tube to the end of the perspex rod and use it to transmit the light from the LEDs.

- As an alternative cut the perspex rod so it is a few mm longer than the electrical conduit and hammer it inside the conduit. Use the perspex rod to transmit the light up the tube and mount the LEDs directly on the bottom of the perspex.

- The perspex rod cannot be used on its own because the mesh screens will scratch the sides of it when they are pushed down around it.


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Re: How to Make a Pentair Nozzle

Post  pmolsen on Sat Nov 21, 2009 1:09 am

Anti-Jitter Filter (Low-Pass Filter):

- I intend to line the walls of the inside of the nozzle with a soft foam material to absorb the pump jitter like in this patent:
http://www.google.com/patents/about?id=AmyBAAAAEBAJ&dq=7264176

- I am planning to try 12.5mm thick EVA 30 foam (Ethylene Vinyl Acetate, 30kg/cubic metre) from here: http://metrofoam.com.au/eva-foam.html. The foam will be glued inside the bottom cap, around the sides of the 50mm long inlet chamber, around the inside of the 30mm ring between the two bottom screens and also around the inside of the 120mm joiner piece.

- The disadvantage is that the foam will reduce the overall diameter of the tube by 25mm. I am hoping that that will not be a problem, given that the real Pentair nozzle appears to only be about 100mm diameter inside. Mine will end up between 125mm and 135mm mm in diameter inside. In the top section where the metal screens are the diameter will remain 160mm.

- My design will have 3 different internal diameters, which is probably not good. Inside the inlet chamber there is no pipe, just the coupling walls (160mm dia) then the foam, reducing the size to 135mm. In between the bottom screens and inside the pipe that joins the two couplings together the inside of the pipe sleeves is 150mm. Subtract 25mm for the foam leaves 125mm. Then inside the screens it remains just the coupling walls with an ID of 160mm.

- To fix the above I could add a pipe sleeve inside the inlet chamber. I do not want to add foam between the mesh screens as it would have to be glued in which would prevent the mesh being removed for cleaning. So I would need to have 3 plastic pipe rings outside the mesh screens to reduce the diameter to be the same as inside the foam further down. The first one would be a normal ring. The next two would have to be split rings with a piece cut out to allow them to be squeezed inside each other. That would reduce the final hole size from 160 to 130mm (the pipe walls are around 5mm thick.) At least it would be closer to 125mm. But first I will see how it performs with the two different diameters before the foam is installed.

- Ok I bought the foam from Metro Foam - 15 Fariola St Silverwater. $30 for a 2m x 1m sheet of 12.5mm thick EVA 30 white. Beautiful soft material. I tested gluing two pieces of it together with standard PVC pipe glue and it sticks well, so that makes it very easy to glue it into the PVC nozzle.

- The ring of foam that will line the walls of the inlet chamber will start 10mm down (up) from the end of the coupling. The inside of the cap will have a circle of foam covering the entire inside, finishing just inside the rubber ring. Then when the cap is screwed on the foam inside the cap will press tightly against the bottom of the foam ring inside the chamber and create a clean joint to avoid any areas that can cause turbulence.

- When shaping the round, angled hole for the tangential inlet hole cut it with a sharp knife or scissors then use a cigarette lighter to smooth the surface. Do not hold it above the flame. Hold it near the side of the flame and carefully move it close enough to melt the surface slightly. I found that the knife tends to stick to the sides of the foam when cutting it and wants to tear it. Apply a small amount of oil to the sides of the knife, but not when cutting where you intend to glue it.

- I do not intend to install the foam initially. I will test and film the stream first with no foam to see how much jitter there is, then add the foam and compare the result.


Last edited by pmolsen on Tue Nov 24, 2009 2:38 pm; edited 4 times in total

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Re: How to Make a Pentair Nozzle

Post  pmolsen on Sat Nov 21, 2009 1:44 am

Exit Ring:

- I will be using a brass exit ring from John at Mad Laboratory.

- Drill a round hole in the middle of the top cap the same size as the brass ring using a hole saw, spade bit (I used) or a lathe etc.

- Cut out a circle or square of 4.5mm plastic 60mm x 60mm from the plastic that was used for the bottom screens. Drill a 20mm hole in the middle.

- Glue the square on the outside of the top cap with PVC pipe glue so the 20mm hole is lined up with the centre of the hole for the brass ring.

- You now have a neat recess into which to glue the brass exit ring. I glued it in with silicone but the silicone does not stick well to the PVC. I would try PVC pipe glue next, or maybe some other type of glue. Use enough so the brass ring is flush with the plastic on the inside.

- The hole in the brass ring is tapered. Remember that the smaller end of the tapered hole faces downwards towards the mesh screens.

- If the brass ring is thicker than the end of the top cap (mine wasn't) you will need two squares of plastic 70mm x 70mm. The upper piece will be as above. The lower piece will be thinner and will have a hole the same size as the brass ring. The thickness of the top cap plus that thin piece of plastic should equal or be just a bit more than the thickness of the brass ring.


Last edited by pmolsen on Sun Dec 06, 2009 9:23 pm; edited 1 time in total

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Re: How to Make a Pentair Nozzle

Post  covewi on Sat Nov 21, 2009 4:04 am

You have been busy. What are the lenght's of each section and overall length of the fountain?

Are you going to fire polish the light end of the plexiglass tube?

Have you tested a prototype of this project or is this it?

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Re: How to Make a Pentair Nozzle

Post  pmolsen on Sat Nov 21, 2009 12:10 pm

The couplings are 158mm long, 165mm with the cap installed so overall length is 330mm. But there is dead space in the middle where they are joined together. I plan to cut about 40mm off the bottom of the top coupling later which will reduce the total length to about 290mm. Hopefully it will not affect the stream.

The full measurements are as follows:

Coupling length 158mm, outside diameter 170mm, inside diameter 161mm. Pipe 161mm O.D., 151mm I.D. Cap 185mm O.D., 32mm deep. So including the cap the total length is 330mm and diameter is 185mm. So the internal diameter is 151mm for the bottom 3/4 and 161mm for the top 1/4 where the screens are. I may have to insert spacers between the screens as stated above which would make it 151mm there as well.

The perspex rod supplier said I could polish the ends by sanding smooth then heating with a blowtorch. I tried that but it obviously requires a very controlled temperature because all I managed to do was melt the end into a lot of bubbles. It also expanded the end so it would not fit inside the 20mm conduit. So I will let the supplier polish the ends ($10).

No testing so far. I am still waiting on the exit ring from John. This is the prototype. I am just documenting everything as I go, then I can make changes if necessary once I test it.

The pump I am planning to use is a 6,000 litre per hour Resun King 5F from eBay for $89 from
http://cgi.ebay.com.au/6000lph-Resun-Water-Feature-Pond-or-Fountain-Pump-K5F_W0QQitemZ170390413779QQcmdZViewItemQQptZAU_Home_Decor?hash=item27ac0f61d3


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Re: How to Make a Pentair Nozzle

Post  pmolsen on Sat Nov 21, 2009 12:37 pm

Cutter:

- I have some ideas about the cutter that I want to test before I discuss them. If it proves successful it may be something that can be patented (or sold to someone who can patent it) since nobody has yet perfected a cutter that does not produce a droopy nose or trailing drips. I realise I am probably dreaming but who knows? Here are a couple of general ideas:

- The cutter must be very high speed for a clean cut / uncut. Nothing I have seen so far produces the necessary speed.

- Because of the high speed the cutter cannot be attached to the nozzle. People deliberately generate turbulance in the stream to enhance the light output by using a solenoid knocker. Because of the high speed required the cutter would act as a knocker and disrupt the flow. From a practical point of view most people mount the nozzle underground so there should be no problem having separate mounting points for the cutter.

- The water jet idea used by Wet obviously produces high speed but it still does not produce a clean uncut, based on videos I have seen from Epcot showing droopy noses. Or maybe the droopy nose cannot be avoided.

- Edit: Nah, I was dreaming about patenting any ideas. I am going to discuss all the ideas in a separate posting.


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Re: How to Make a Pentair Nozzle

Post  John on Tue Nov 24, 2009 1:06 pm

WOW THAT IS AWESOME! I can't wait to see the results. What size of arc do you expect to get?
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Re: How to Make a Pentair Nozzle

Post  pmolsen on Tue Nov 24, 2009 1:21 pm

The arc I need is 3m x 1.5m high. But I am hopeful that it will produce a bigger one than that if necessary.

I bought the anti-jitter foam yesterday. See Anti Jitter subject above which I have edited with the details.

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Re: How to Make a Pentair Nozzle

Post  John on Tue Nov 24, 2009 1:37 pm

While reading that page on the eva foam that sounds like a good idea. One question though, do you suppose that it will absorb water? I know it said, "low water absorption," but low doesn't mean no water absorption. Do you think this will change with age of the foam?
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Re: How to Make a Pentair Nozzle

Post  pmolsen on Tue Nov 24, 2009 1:48 pm

According to the specifications the amount of water it absorbs it extremely minimal. I do not expect a problem. It is "closed cell" foam which means it is made up of a lot of tiny air bubbles that are completely enclosed in plastic with no joins between the individual air bubbles. The material itself (EVA) is just another plastic and plastic itself does not absorb water.

If it did happen to be a problem then it would simply be a matter of painting the whole surface of the plastic with the PVC glue after installing, but I do not think it will be necessary.

I am still a bit doubtful as to how effective it will be. Whilst it is soft it is nowhere near as soft as a tube of air used as an anti-jitter filter by others. There is nowhere near the same volume of air to be compressed.

Having said that, when applying for a patent it is usual (necessary?) to have tested any claims made. I would expect that the person who lodged the patent referred to above would have tested the concept and found that it worked. Although I do note comments elsewhere that the home made nozzles perform better than the commercial ones. Maybe it only removes some of the jitter.

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Re: How to Make a Pentair Nozzle

Post  John on Tue Nov 24, 2009 1:55 pm

I'm really impressed with that design and I hope that it works for you! That comment about the homemade nozzle being better than the commercial ones was just an observation.

I too would suspect that the patent would have been tested to make sure it works before the patent was granted, but how does the patent office know if the patent is going to work or not?

The beauty about your system is that if you need extra absorption then all you need to do is build a filter somewhere in the middle, and it probably won't have to be as large as most since some of it is getting filtered.
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Re: How to Make a Pentair Nozzle

Post  pmolsen on Tue Nov 24, 2009 2:10 pm

The patent office does not test patents but the designer is expected to. You cannot just patent a theory. It has to be something that someone "skilled in the art" as they say could make based on the specifications in the patent.

That reminded me of another point in the original Pentair thread. Someone commented that the Pentair nozzle did not have a razor sharp orifice and did not use a tangential input. There is a simple reason why - those ideas are patented. A commercial manufacturer cannot use any ideas that have already been patented or else they have to pay royalties to the holder of the original patent if the patent is still current. It lapses if the holder does not continue to pay the (high) annual renewal fee.

Fortunately for us we can use any patented ideas we like for private use as long as we do not start marketing our products.

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Re: How to Make a Pentair Nozzle

Post  covewi on Wed Nov 25, 2009 1:51 pm

What do you think about this

http://www.usplastic.com/catalog/item.aspx?itemid=23645&catid=733&clickid=searchresults

1/4 inch thick with 1/4 inch hole for first screen and 1/8 inch thick and 1/8 inch hole for second screen

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Re: How to Make a Pentair Nozzle

Post  pmolsen on Wed Nov 25, 2009 11:36 pm

It would certainly save a lot of time and effort.

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Re: How to Make a Pentair Nozzle

Post  pmolsen on Sun Dec 06, 2009 9:25 pm

Nozzle Test 1:

Test 1 was conducted with a hose connected to a tap. Produced a beautifully smooth stream when only jumping about 1.5m long by 1m high:







Unfortunately when I increased the pressure to a 4m long x 2m high stream it broke up badly from the top of the arc onwards. Will have to progressively remove/modify the various parts of the nozzle to determine the cause. Sad

The two halves of the nozzle also blew apart under the higher pressure. I will have to insert the small stainless screws to hold the upper coupling to the inner pipe sleeve.

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Re: How to Make a Pentair Nozzle

Post  John on Mon Dec 07, 2009 7:58 am

My experience has been that it probably has to do with the pump jitter. I think that is the problem with most nozzles. Those nasty pulses from the pump are just going to destroy your stream in the end. Did you build the internal filter? If you did you might want to consider building an external filter before you start taking things apart. Test that see if that is the issues then you can take your nozzle apart if that doesn't solve it. What size is your nozzle diameter (overall size)?

I think your nozzle is expertly constructed. It looks really nice and clean.
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Re: How to Make a Pentair Nozzle

Post  pmolsen on Mon Dec 07, 2009 1:21 pm

There is no pump jitter as I am using the tap, but there is variation in the mains pressure. That of itself surely should not produce the bad result, which is obviously turbulence. It should just result in the stream wavering up and down shouldn't it?

The internal diameter is 150mm. The internal diameter of a real Pentair looks like about 100mm.

Update on the ring installation. Silicone does not stick to the PVC. I pushed on the ring from the outside and it fell in. Will try some Selleys All-clear which is stickier. Failing that I will try using pipe glue, but I do not think it will stick to the brass very well.

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Re: How to Make a Pentair Nozzle

Post  John on Mon Dec 07, 2009 3:30 pm

Oh, I didn't see that you were using the tap. If the pressure were jittering fast enough it would still break up your stream, but I think you have it right using the hose. It odd that you say that it breaks up after the pinnacle, because almost always with the exception of ridiculously high flow rates that it breaks up after the pinnacle.

Here is the bigger question, why does it always break up after it reaches its pinnacle? How does water move in the air? I know that we mentioned earlier that it could be due to the drag of the air on the water. Do you think that it is the same as the fluid in a pipe? Do you think that if it could continue you would get that fully developed parabolic profile?
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End Results?

Post  scrafy on Wed Nov 03, 2010 10:37 am

Hello PMolsen,

can you share the end results of your nozzle? Did it work in the end as you expected? Was the stream laminar? Did you try the foam inside? Can you share more photos or maybe a video?

Thanks a lot!

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Re: How to Make a Pentair Nozzle

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