Water Heater Housing

This is going to be part of a home brew mashing temperature controller. I was given a 400W cartridge heater. Its a bit like a towel rail element, but smaller and without a built in thermostat. I needed to come up with a way of mounting it in a pipework loop which will include a pump and a coil which will be immersed in the mash.

The heater is 9.5mm diameter. This is annoying because it it was 10mm it would have been far easier to secure: 10mm plumbing fittings would do. I used a 10mm compression fitting with an O-ring to seal it rather than an olive. The olive is still there, but I filed one of the sloped sides off leaving it with a nice 1mm wide flat face to bear on the O-ring. I hope that this will push the O-ring into the seal. If I had left it as-is, the sharp, sloped, edge would just cut into the ring, or push it outwards rather than in. I hope this is clear in the photo.

I “pressure” tested the seal by attaching a meter of plastic pipe and a funnel, which was hoisted up in the shed roof for a day. Although its not tight enough to prevent you pulling the element out, it does hold water. We’ll see how it behaves at 80°C and with a pump.

The rest of the housing is made from 22mm tube so there’s a good amount of water flowing round the element. The majority of the plumbing is going to be standard 15mm, so what I really needed was a 10mm x 15mm x 22mm unequal tee. But these just don’t exist in the shops. I made one by soldering half a 10×15 reducer to a most of a 22x10x22 tee. The fittings need to be compression rather than solder, because if I have to heat up the frankenstein tee to attach pipework, the two halves will un-solder and fall apart!

At the moment I usually mash about 6 litres (for 1500-1800g of grist) in a large stainless steel jam making pan with a lid. To maintain temperature I put it in our electric fan over on the lowest setting, which happens to be about 60°C. On the kitchen worktop, at 90°C, this cooled by 4°C in 6 minutes, or 0.01°C/s. 6 litres of water, with a thermal capacity of 4.2 J/K, cooling at this rate, is giving off 280W, so my heater should be able to maintain temperatures in the range 40-80°C. It might take a while to heat up a pan of cold tap water though!

Homebrew Filter Tap

Several years ago I made super gizmo mark 1. It is a tap for the bottom of my homebrew boiler, a large plastic bin with a kettle element at the bottom. These come with a simple tap which has no filter, so all the hop leaves, seeds, and sludge pass through. The mark 1 improved on this by adding a filter with a large surface area so it would still empty the bin in a reasonable time:

The problem with this is that the filter is at the same level as the tap, which is 4 or 5 cm from the bottom. This means lots of tipping, propping and messing around to get the last few litres out. Last summer I decided to make mark 2, with the filter as near to the bottom as possible. It would also have more, smaller, holes to improve flow and filtering.

The starting point was some 28mm copper pipe. To get near the bottom of the bin, this would be squashed flat. But not completely flat: it would need an internal channel for the liquid. I worked out the dimensions of the resulting rectangular channel, and got a strip of aluminium cut the required size (2x38mm). This is a bit smaller than the channel, to allow for the curvature of the edges, and to prevent the strip jamming in the pipe. Then I crushed the copper tube onto the ali strip, using a vice with plastic jaws:

The next step was to drill a lot of 1.5mm holes:

The ali strip prevented burring on the inside of the copper where the drill broke through, but not on the back. I countersunk all the holes with a 6mm drill.

The tap section was made from a collection of 15mm and 22mm parts and offcuts:

The tank fitting allows the whole tap assembly to be removed from the plastic bin for cleaning. Mark 1 had this feature, but was installed from the outside. Mark 2 has to be installed from the inside, because of the size of the flat filter section. This means the actual tap (a 15mm tap isolator) has to fit through the hole in the bin, and can’t have a handle. The tank fitting is a large lump of metal so it was a pig to solder.

I closed the ends of the filter with strips of copper scrap and solder. The hole for the outlet was made by drilling a ring of small holes: it can’t be through both sides of the filter. The outlet is a 22mm elbow:

 

The finished article: