Female complications, day 35 Rising pressure

I really should build a more efficient steam boiler for Thrymheim this summer and install a good steam engine electricity generator. We don't exactly have a shortage of firewood, especially with the labourers clearing forest for fields and cutting down branches and small trees that won't make good planks in the sawmill, but works as firewood once it dries. Then again, Thrymheim is a marvel in energy efficient heating by this world's standards, because it is well insulated and there aren't many fireplaces lit, but better is better. Most of the firewood is used by others on the island for cooking and heating.

But for future steam engines the requirements are different than for heating, and the design of the engine needs to be more efficient and able to cope with higher pressures than existing ones, which I have not tested to the limit. I have been thinking about an improved steam boiler of horizontal or vertical model. I have seen pictures and cut-outs and such in media and museums of steam boilers, including an advanced horizontal marine model with a large horizontal short cylinder that is the water tank, with a smaller fire tube at the bottom separated into upper and lower part in the fire end with ash grates. At the rear of the main cylinder there is an extension so the smoke from the fire tube goes up and is turned back to the front through many small pipes though the water, and all those pipes have a lot of surface area, so the water is heated by the smoke as well as direct fire against the roof and walls of the fire tube at the bottom. The smoke then collects outside the cylinder at the front and goes up to a chimney via a valve-damper.

It is a relatively compact design that should be quite efficient and relatively manageable to manufacture with manageable weight, and thus steel consumption. It should be fairly secure with long metal rods holding the main boilers flat front and back sides together along with all the smoke pipes and the fire tube, and a whole bunch of rivets. An extra oblong tank run along the top of the boiler with connecting pipes at the front and back to the big boiler cylinder below, which should mean safer steam separation and better circulation of water and steam.

It is important to try to ensure that only steam enters the steam pipe to the steam engine with as little water as possible to avoid hydraulic locking - liquid cannot be compressed. I hope it will be enough with two safety valves, a regulator, pressure gauge, water level glass on the front, water injector etc. Maybe have an internal float that releases some pressure to a whistle if the water gets too low. A whistle is nice in any case, and we can of course make it whistle with a handle too. The main problem is the joints in the boiler's pieces, which is a manufacturing problem, and more likely to fail in a weaker part of the material, and I'd rather have a design that fails safely, and is 'easier' for Olafr and blacksmiths to make well, than something that is less work to make but hard to maintain or fix.

So another project for Olafr is a new improved boiler for a steam boat, because the steam engine is primarily limited by the boiler and its pressure. Even a small steam engine can have great power when it starts to move - if it is fed with high pressure and is not in a dead locked position. I know those Stanley steam cars in the USA in the early 1900's, all had two double acting cylinders of about 10 cm diameter, and with their high pressure boiler at around 600 psi or 41.4 bar, the engine produced 6500 kg of force immediately when the steam was switched on from standstill, and the boiler determined the total power in the system. The calculation is fairly simple. Area of 78.5 square centimeters x 41.4 bar, which is about same in kilograms/cm², x 2 cylinders, gives 6500 kg. I believe the same vehicle and engine were sold in 10, 20 or 30 horsepower models depending on the boiler, but the engine could produce more than 100 horsepower for short periods, because it is all about power over time.

I won't build any steam engine with such high pressure, but I hope to get a more powerful steam boiler that is compact and has good heat transfer, which existing ones don't have. Even 'low' pressure 5 to 10 bar feels uncomfortably high in a boiler, until I am very sure and until a couple of generations of boilers have been tested over a few years. I won't even try the 25 bar which is the lower limit to be seen as high pressure steam, and certainly not 40 bar or more like the Stanley boilers used. But I can take lessons from the design of the Stanley Steamer boiler's vertical design that puts out the fire in case of leak, and fails safer, and how they made the boiler lighter with coiled steel wire, because it's not so much about the weight of the steam boiler, as failing in a save manner and thinking about manufacturing problems and material problems. But if I'm going to make a steam road vehicle, weight and size and high pressure becomes important.

So it will be a vertical design inspired by the Stanley Steamer, just not as advanced and with maybe a quarter of the pressure. About 70 cm diameter and 50 cm high, two thick end plates with 23 4 cm pipes connecting the end plates for the smoke to pass through, all surrounded by a steel cylinder with a recessed channel for the end plates, with heat shrunk steel bands at the ends pressing the main cylinder around the end plates. The pipes through the end plates are sealed by running the pipes through holes, and then forcing the pipes out with mandrels. And maybe welding. We will see if it will be copper pipes, or steel pipes. Mixing metals is not a good idea. Outlets for steam, water filling, pressure gauge and level measurement are made through the end pieces. To reinforce the cylinder to withstand pressure, about half a kilometer of 3 mm steel wire is wound between the crimped steel bands over the whole area, and in a couple of layers. After that, the water and steam tank is finished and will be about 46 litres. A lower section with grate and firebox to heat the approximately 180 dm² surface area of pipes and end plate provides heat, and an upper section with chimney and water distillation completes the design.

Not the easiest boiler to make here, but I have high hopes for decent efficiency, steam production, size, weight and safety. Making a boiler with 500 to 1000 smoke pipes like the Stanley boilers is far too problematic and too high a risk of failure in manufacturing, even if they had several times more heating surface and thus power and efficiency. Making a more advanced solution like the Doble boiler with direct converted water without a tank is not something I can do without having suitable fuel. I am limited to coal and wood. Making any woodgas like solution seems unnecessarily complicated, and so is using pine tar as fuel.

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I have shown sketches and drawings of how Olafr and the others will make the different segments, and join parts together. I'm mostly worried about the boiler not really being able to be cleaned inside, because even if there is a small inspection hatch, the pipes will be in the way. Which is a big reason for the distillation of water for the boiler, and the condenser that recovers most of the water and heat, but in the long run it's inevitable with some build up, and it is possible to take the boiler apart, it's just a lot of work. If just one or two of the pipes start to leak, we will probably have to resort to the quick and dirty solution of just hammering in plugs to seal them.

Built-in water distillation also helps on larger ships by purifying seawater to drinking water on longer voyages, even if there is a limited amount of fuel. There will also be a lot of waste heat through the chimney and I intend to use it for water treatment or warmth. Then again, it is not certain that this new boiler is a good match for my larger steam engines, but remains to be seen. Everything is a balance.

It's good that Olafr already made a simpler wire roller to roughly manufacture all the steel wire. I hope there will be a finer and more advanced copper wire making machine in the future too, because I need so much copper wire.

Before I leave, I ask Olafr to make five more RobA knives when he have the time to spare, because Raneigh will get one sometime in the future, and I think Asta should get one too in a few months or so, and a couple more are just handy to have. I might have to give knives to Ryla and Agnes quite soon. After all, they've become a sign of someone tied to me and Thrymheim, and more than just as servants. It's a sign of status. He's also going to make Kari a sword of the same type as my own, but much more ornate and a bit flashy, as it is the weddings morning gift. She's a Storman, and it's expected for a Storman to carry a sword, even if she's a woman who hasn't trained with a sword. Kari is so hard to give a good morning gift to that it feels a bit ridiculous, because I'm not content with it being an empty gesture.

Once back in the workshop, I continue to make more manometers, valves and parts for the air turret. I need to build several larger gauges that go to about 20 and 30 bar, because I will be testing the steam boiler pressure to maybe 15 bar or so, not to the destruction of the boiler, but higher than I intend to use, and although we will be testing with air pressure and water without heat, we will eventually have to test with heat as well. The first real fire and steam at maximum pressure will be nerve-wracking. I'm glad I sent along drawings of the injector parts etc so Digraldi can mould them even though I could have made them myself. I will also need to build several small miniature pressure gauges to have for air pumps and future air rifles, which is its own problem due to the huge pressure, but they will be compact with small size and scale that doesn't need to have high resolution or accuracy, which makes it easier.

Ciara knocks on the door, comes in and reminds me of combat training with Alith, but when I put work aside, I see that she is leaning forward with her skirt pulled up and wiggling her butt at me with her jewel visible, which change priorities. It's actually quite rare that we have anal sex these days, because Ciara prefers kissing and hugging during sex, and preferably riding or lying on her side. We actually don't have much sex compared to my other relationships, but our relationship isn't based on sex and I love her no matter the amount of sex, although her need to know where I am and that I'm safe can sometimes be annoying. I wasn't happy when Iselin showed up with Ciara and I first saw her, but now I love Ciara only slightly less than Iselin and on par with Kari and Jane, and am glad she is in my life. Our relationship has its issues, but she is my most solid support.

It takes some time for my brain to focus after my moment with Ciara, so Alith is a bit dissatisfied as the training is only half-hearted, while she wants to show what she has learnt from Heimir and Ryla-Agnes. I'll feel those two bruises in the next few days. I also believe that Alith is trying to get a bit of revenge for her losses when I used the flash illuminator on her last time and 'pwned her' twice. That was interesting because she was annoyed, pleased and sexually aroused - all at the same time.

"Robert, just so you know, we have started to give Gisela combat lessons. Gisela wants to learn weapons just because she can, and feels that she needs to be able to protect secrets like radios in case someone tries to take it away from her. So, like other in the household, she has started to receive basic training in handling different weapons and fighting in a shield wall. But she really like practising with a crossbow, and like Elvira, Gisela finds pleasure in the fact that even a well-armoured knight on horseback should be afraid of the crossbow. There is a new bet on whether Gisela will want to become a shieldmaiden just because she can, and we understand that desire for freedom and not feeling helpless." Of course shieldmaidens understand that. Alith grins and continues; "There is also an old ongoing bet about possible sambo or other official sexual relationship with you, where Gisela has quickly become a rising favourite, overtaking both me and Elvira."

"I assumed you knew that Gisela offered to become a wife or concubine just yesterday. And that I said no."

"Yes, we know. But you have to admit she have quite a lot in common with the others. Beautiful with big breasts - which I know you like!" Alith pushing her chest towards me and suggestively and playfully wiggles her boobs. Sure, I don't complain about big boobs, especially not to look at, even though I prefer medium-sized ones during sex. "Gisela is also a freed slave that you have 'rescued'. A young untouched virgin with long and pretty blond hair, strong will and desire to stay in this culture. She likes art and is educated. Noble born but fallen, and she is exotic. And now you know that she desire to be you concubine."

Shit. She pretty much is the average of my existing sambos. Ow! Fuck! Alith use my distracting thoughts to give me another bruise, and looks so smugly pleased.

"Let's just stop training for today. My mind and will just isn't here."

"That's when you should train! Can't expect enemies to be considerate!"

"If this was a live or death situation, adrenaline would ensure I would be focused. Let's just stop." I move closer and whisper: "By the way, there are a couple of new secrets you need to know about as head of security, so please wait for me about 40 minutes from now, as I need to use the exercise cycle and shower. Bring a flashlight."

"Okay."

It is so nice to be able to say such time indication and know it works. I should have built pendulum clocks earlier. Everyone also likes to know when breakfast, dinner and supper are, and it's the same times every day, although midday meals are generally simpler food and more flexible as that is in the middle of the workday, and some don't even have that meal. The norm is pretty much: Wake up. Work. Very late breakfast. Work. Maybe something light that can be brought along. Work. Evening meal. Work and social life. Sleep.

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