THIS TAPE HAS BEEN RECORDED ON MAY 2nd 1979 AT 13 AVON DRIVE BARNOLDSWICK. THE INFORMANT IS STANLEY GRAHAM WHO WAS THE ENGINEER AT BANCROFT MILL AND WHO HAS BEEN THE INTERVIEWER ON MOST OF THE TAPES..
I am going on describing the pictures in the Bancroft Folio. We have now reached the section where I want to say quite a lot about the boiler because it isn’t described in any of the other interviews.
This in a picture of John Plummer the last firebeater or boilerman that I had. He was there with me until the mill closed. John had fired boilers all his life and used to entertain me with stories of carrying coal across the deck of an ice-covered trawler from the fish hold to the engine room while he was in a gale raging off Bear Island. He fired on Fyffe’s banana boats and said it was always worse on the way home when the refrigerating plant was eating steam. Occasionally, if the price collapsed they would stop the boat, open the hatches and throw all the bananas overboard and then turn round and steam back to the West Indies for another load.
John was on the dole when I set him on. He had a large family and actually got less for working at Bancroft than he did whilst on benefit. This says quite a lot about the man. We got on well together and I enjoyed working with him.
Now I should explain that a boiler-man in Lancashire is generally referred to as a firebeater but you'll probably find that I call him a boiler-man or a firebeater or a stoker. I might call him by different names because anybody who has studied my history will realise that I am not a true Lancastrian and some words do come easier to the tongue than others.
This picture then is John Plummer sat in his chair in the boiler house and he is
actually working hard there. Some people find this very hard to understand. Little story here, I’ve deliberately restrained myself from putting too many stories in but we’ll have a little one here that illustrates a point.
I was asleep in the engine house one day, quite a usual thing to happen, the sound of the engine running at 68 beats to the minute, exactly the came as a human heart beat and nobody could sit long in the chair in the corner of the engine house with the tail rods sliding and bell crank flying backwards and forwards in front of them without becoming mesmerised to a certain extent and going to sleep. Of course I was fairly proof against this but every now and then allowed it to happen to myself and went off to sleep for probably half an hour or something like that. John used to do the same down in the boiler house. We had a managing director at that time, a fellow called Peter Birtles who came down one day and found me asleep in the engine house and woke me up. He said “You know Stanley I don’t pay you for sleeping. And what's more I have just been down in the boiler house and your firebeater’s asleep as well!” I pointed out to him that the shaft was turning into the mill, the steam was at the right pressure and the weavers were working normally so I couldn’t see what he was worrying about. His firebeater was asleep so he wasn’t shovelling coal. I was asleep so the engine was running all right. And I pointed out that what he didn’t know was that both John and I had been at work since midnight repairing a fault in the heating system so his mill could start on time. I suggested he should wait until things went wrong and then come down and play hell.
Now this might seem a bit of a clever story, and a bit of a funny thing to say, but it actually illustrates very well a point which I've already made once before on these tapes. The good men were the men where the job was going on, everything that should have been done had been done and they were taking it easy. This also applied to things like weaving, one sure way of telling whether the engine was running at the right speed and smoothly and whether everything was going well was to go into the shed and just have a walk round. Now if you saw a lot of weavers on their feet bent ever the loom taking ends up and things like this you could bet a pound that there was something wrong somewhere. It wasn't necessarily something to do with you, it might have been something else but there was something somewhere. If on the other hand you went into the mill and found that several of the weavers were sat at the end of their looms, probably having a drink of tea and all the looms seemed to be running and everybody had a smile on their face things were going well, and that's the time when you are making money. And we took the view, rightly or wrongly, in the engine house and boiler house that we had a lot of peculiar hours to work, more about that later, but we had a lot of early starts and late nights and we took the view that we took our rest and meals and our cups of tea whenever the opportunity presented itself. That’s the reason why very often you’d find John taking a cat nap and myself taking a cat nap at the same time. Some people might say that this was reprehensible, but in fact the hours that we were working, it wasn't possible to work them and keep going all the time. If you did, you’d make yourself poorly, and hence the reason for it. So that's why John has his armchair down in the boiler house and he’s got his fent over his table and his pot's there all nice and clean. Very difficult job to keep anything clean in the boiler house but he used to do his best. We used to bash a bit of whitewash about every now and again, you can see that we have just had a do at those boards behind him. It was a rough job admittedly, I mean the whitewashing, but it did just let a bit of daylight in and brighten things up.
You’ll see the tools of his trade all round him, shovels, rakes and implements of destruction. Look at the floor, terrible, flags up, flags down, absolutely shocking that floor in that boiler house. This was caused by the fact that over the years drains had leaked and washed the infill away under the flags and they'd settled and it really was in a bad condition. It had got to a the stage where we had to prop the boiler wall up because the footings had gone and the wall of the boiler settings, the wall of the flue was trying to fall out. One corner of it at the front had at one time fallen out and been re-built but they never really got to the root of the job and the rest of the wall was cracking. So what we did was prop it up, we put wooden frames in, wooden timbers in and propped it up against the shed wall which if nothing else, made it safe. It stopped it moving and enabled us to bung up all the cracks up and stop any air leaks in the wall.
This is a picture of half, or just over half of the front of the Lancashire boiler. I could go on for some length of time about this, and probably will. What you are looking at there is the front end of a cylinder made of mild steel ¾ “ thick. Riveted construction, nine feet in diameter and approximately 28-30ft long. Two tubes run through the middle of it, this is a Lancashire boiler. A Lancashire boiler is a shell boiler with two tubes, a Cornish is a boiler with one tube. The Cornish boiler was originally invented by Trevithick and the Lancashire boiler is Fairbairn’s improvement on the Cornish boiler. There was a further improvement, I can't tell you who did it, which was a boiler like the Lancashire but with a third tube where the mudhole is below the tubes. This was called the Yorkshire boiler but they were never a success and quietly vanished into history.
There is more to a steam boiler than meets the eye. I don't intend to start airing my knowledge of steam boilers here by going into a lot of esoteric information about the spacing of rivets and thickness of plates. I take the view that there's plenty written down in the text books and if anybody really wants to know all that all they have got to do is to start doing a bit of research.
However, there were certain things about boiler construction which we had to take note of in order to run the boiler successfully, economically and above all, safely. The thing to remember about a boiler of this description or indeed of any other boiler, is that what you are using is a very large pressure vessel, and a very large pressure vessel is a potential bomb. It's a potential danger. In the old days the way they used to describe this was to point out to the innocent firebeater that a Lancashire boiler this size or rather slightly smaller than this, a boiler running at 140psi contained enough energy to lift the boiler together with all its contents 7,000 feet into the air, vertically. Another way of putting it is that you have got to fire this boiler two days and burn 5 tons of coal to get it up to operating pressure and temperature. Another way of putting it is that some idea of the power locked up in a Lancashire boiler could be judged when we were emptying the boiler at the holidays or at any time when we had to do maintenance on it. Anybody who has ever beard the steam coming out of a big boiler like this, out of a 3” pipe sounding like a jet aircraft taking off and blowing like that for approximately 20 minutes will have some idea of the power and force that was locked up in there. This sound was common once at Barlick holidays, everyone knew what it was and it was part of normal life.
So a boiler is a very dangerous beast but if looked after is perfectly safe. This was the function of the engineer and the firebeater.
One interesting thing about boilers and boiler insurance and something which a lot of people are surprised about when I point it out is that the government never has anything to do with boiler safety or maintenance. The only thing they are interested in is when something goes wrong with the boiler. This sounds a bit funny but in actual fact the system is quite simple and very sensible. The insurance company who carries the risk of the boiler is responsible for inspecting that boiler and making sure that it’s fit to stand the load that's going to he demanded of it. As simple as that. The only law the government enforces is that a boiler must be inspected and certified safe at least every 14 months. In practice this means once every 12 months. You can go a month over or so and still be legal.
So we are looking at the front of a 9ft. Lancashire boiler. Boilers were always classified by their width. The reason for that is that due to the design criteria of a Lancashire boiler, if a boiler's 9ft wide, it stands to reason that for a certain pressure it's going to have a certain thickness of plates and a 9ft boiler is going to be 28 to 30ft long anyway. There is no reason to give any further indication of the type of boiler than to say it’s a 9ft. boiler. Any engineer who has had experience of them knows exactly what you are talking about. This boiler was made by Hewitt and Kellet of Bradford in 1914. It was bought by the mill brand new and I have been told by an old fellow that it was delivered at the mill from Bradford by steam traction engine on a large trailer. He said that the corner of a house had to be taken off in Wapping to allow it through. It would be one of the first things to arrive on the site, the boiler was installed on its settings and then the boiler house was built round it so this boiler would almost certainly be on site during the first world war waiting for the rest of the mill to be built and for the engine to be installed.
All the fittings on the boiler, when I say fittings I mean the fittings which are necessary to the safe running of the boiler not to the firing of the boiler. These are all Hopkinson fittings. Hopkinson’s of Huddersfield, valve manufacturers and one of the most respected names in this field, especially when we are talking about Lancashire boilers. At the time when this boiler was put in Hopkinson’s just about supplied the fittings for every boiler installed in the country. And deservedly so because they had a tremendous reputation for very fine workmanship and very reliable and efficient valves, gauges and associated pipe work.
Looking at the front of this boiler, you'll see that we are looking at one of the tubes. There is another identical tube on the other side. The fire is contained in the front of the tube on a set of cast iron fire bars. You can see the knobs on the end of the carrier bars sticking out under the Proctor coking stoker, under the door where you can see the light shining through the right hand poker hole. This boiler is working hard and inside the furnace the temperatures are high enough to melt steel.
The Proctor unit wide ram coking stoker was a very good stoker there are no two ways about that but like most other things it had its limitations. One of these was that it was only a good and efficient stoker when it was firing at a sufficiently high enough level to give you a complete coverage over the bars. This means that if a Proctor stoker is firing hard it's a good stoker but if you are firing light like we were most of the time, because this boiler playing with the load that it had on it, we were running very inefficiently. Now you can see that by looking at the fire box door you can actually see the fire above the top of the door on the right hand side. Normally you shouldn’t have been able to do that. You should have been able to see a bit of fire through the poking holes in the doors. The doors by the way are very narrow, and immediately below that aluminium plate on the front which has Proctor Unit wide ran coking stoker written on. We very seldom ran at this level and this was one of the reasons why we used to make smoke because we couldn’t cover the bars and we were getting excess air in at the back of the fire. This meant that we were getting incomplete combustion and smoke. A pity really, because the Proctors weren’t a bad stoker. They took quite a lot of maintaining but then every stoker does, there is no such thing as a stoker for burning coal in a boiler that doesn't require quite a lot of maintenance, it has a very hard job to do because inside the furnace there are some extreme conditions, nothing in there can be greased because of the heat, everything is subject to attrition from the heat and also from dust and fine clinker dropping on it which is similar to finely ground glass and it would wear anything.
The construction of the stoker was mainly cast iron. The action of the stokers was that there were two main parts to the Proctor stoker, the fire bars, the knobs of which you can see at the bottom underneath the curved shield and the ram which is inside the box which says 'Ram Coking Stoker' on it. You can see the actuating lever for the ram on the left hand-side. What happened was that as the stoker was working very quietly away, probably only on slow firing, about four or five strokes a minute. On high fire perhaps 30 or 40 strokes a minute. The ram moved forward and pushed a measured amount of coal down on to coking plates at the front which are on top of the door, you can see the back edges of them actually. These coking plates were made of cast iron and soon attained a red hot temperature. They acted as ignition surfaces for the coal when it went in. The heat there began to coke the coal, in other words it began to drive the volatiles off. The idea of this stoker was that as the volatiles moved down the furnace under the action of the draught caused by the chimney they would be ignited and burned completely by the bed of hot coals over which they were travelling. If you had a very small fire, a short fire due to very light load there wasn't enough fire there to burn all the gas off that was coming off at the front and you used to get smoke, it’s as simple as that.
These bars and the grate were self-cleaning. What used to happen was that underneath the curved shield there was a shaft with a lot of cams on it, one cam for each bearer bar. These are the bars with the large knobs on the end you can see under the shield, there were twelve of them. Each bearer bar carried two more fire bars. The cams on the shaft were set so that they moved the bearer bars in a certain sequence. What it meant was that all the bars moved forward together but when they were moving back they moved back in odd ones. This meant that when they were coming back they came back individually and didn't move all the coal back and all the clinker and ash and cinder back. But when they went forward they took it all forward. The net result of this was that the fire was quietly moving away down the firebox all the time as long an those bars were running. The idea was to so arrange thing that they ran at just the right speed to carry the fire to the back of the bars just as it gave over burning and became dead ash and clinker. Then the dead ash and clinker falls over the ends of the bars at the back into the ash pit. Once a day, or whenever is thought necessary, you opened the ash pit door by means of a handle under the bars and slide a long handled curved shovel down and bring the clinker and ash out. Shovel them into a barrow and then lift the barrow out of the boiler house with a small crane just inside the door. We kept the ashes across the other side of the yard and anyone who wanted some for repairing a dirt road could come and take what they wanted. We never had a waste disposal problem.
In other words it was possible to run this stoker all day from starting in the morning to finishing at night without opening the firebox door. This was a great benefit because it meant that you weren't allowing excess air to get into your fires. In the hopper above was the supply of coal for the stoker and above that can be seen the chute which feeds it. This was fed by an auger from the bunker and this bunker faces the boiler. I was actually stood with my back to the bunker when I was taking this picture. In fact I was probably stood in the bunker itself. The hoppers held about 30cwt of coal and under normal circumstances, normal sort of firing, were probably good for about half an hour or something like that. We used to burn on average at Bancroft, with 350 looms running about 1000 tons a year. This consumption varied from about, say, 12 tons a week in summer to perhaps 30 tons a week in winter, but on average we got through about 1000 tons a year. At the time the mill closed down, singles, which was the size of coal to used, and by the way we were working on outcrop coal, we were using open cast because it was slightly cheaper. Singles were about £35 a ton. And so all the total energy charge for the mill was £35,000 a year plus the electricity bill which was about £40 a quarter. This was very cheap for this time for a unit of this size. The Lancashire boiler, even though inefficiently fired, and the steam engine, even though it was an antique, were efficient. What people fail to realise is that the overall thermal efficiency of mains electricity at the point of use in the mill is something like 7%. In other words, out of every 100 tons of coal burned in the power station, 93 tons is wasted. We were more efficient than that and this was why our energy costs were so low.
Fittings on the front of the boiler. On the left of the stoker can be seen at the bottom the electric motor and the two gear boxes and the chain drive in the front in that case which drove the stokers. They drove the cam shaft and an eccentric which powered the ram above. Same arrangement on the other side only right handed instead of left handed.
You can see on the front of the boiler, in between the two hoppers that held the coal a round disc and a pointer to each side. This was the water level pointer and pointed to the gauges at each side which were the water gauges. The pointer is a reminder of the ideal level of water for the boiler. We never used it as a guide but polished it each day. Our guide was the level in the water gauges, these are positioned so that if you can see a level in the glass tubes you are running safely. The water gauge is a glass Pyrex tube which is connected with the space in the boiler at top and bottom through the polished bronze fittings. These are under boiler pressure and they show the level of water in the boiler. The idea was to run somewhere near where that pointer was pointing, more about that later, about water levels in the boilers. These were Hopkinson gauges and were very good. It may sound dangerous, I mean a glass tube on the front of the boiler with the boiler water in it and under full pressure from the boiler, one might be forgiven for thinking 'What happens if that glass tube bursts.' It's a good question, in the early days of boilers it was a disaster because there was that much steam blew out of the broken gauge that you couldn’t hope to get near it. Steam and boiling water, you'd be scalded to death before you got near it. This assumes you weren’t badly scalded when the tube burst because they do occasionally. Two things safeguard against any trouble from that source. The first is that the polished brass case that you can see is a guard, it is open at the back but the front of it is heavy brass and two very thick pieces of very heavy glass. The idea of those was that if the gauge tube did burst they stopped any glass or scalding steam flying forward and hitting the firebeater. It was very dangerous to run with those off in fact. Nobody with any sense ever did it. There was another safety device in the brass cocks at top and bottom of the gauge glass. Inside a chamber cast into the passage which allowed the water and steam to enter the gauge glass was a bronze ball. Normally this sat in the bottom of the chamber but any sudden rush of steam or water past it threw the ball against a seating and closed the passage to the boiler. So if a glass blew the steam ands water were shut off instantaneously. Very simple idea and very effective. Very safe and we never had any problem when a glass burst as they did occasionally. The thing that blew them was that erosion inside the tube when blowing the gauges down to test them used to thin the tubes down. I always fitted new glasses every time the boiler was down.
The reason for the cocks at the top and bottom of the gauges, there are two reasons; one in so that you can turn those cocks off for essential maintenance on the gauge, say if the tube breaks; and the other is that during the day you perform an essential operation known as 'Blowing the gauges down’. Blowing the gauges down was done to make sure that the passages from the boiler into the water glasses, the actual tubes, was clear of compo and frothy and sediment. If you didn't blow then down regularly, they quietly bunged up and once they got bunged up the only way you could clear them was to empty the boiler and take the gauges off and rod the holes through the boiler plate out. This is a big job and costs a lot of money because you have got to burn 5 tons of coal just warming the boiler up again. Apart from that, it's tremendously unsafe because at no time do you know exactly how much water you have got in your boiler and that is essential. You have got to know how much water there is in the boiler at all times. So what you do is blow them down a couple of times a day and just make sure that the passages were kept clear. In point of fact, we only needed to blow these down probably once every two or three days because we looked after the quality of our feed water.
Look at the bottom of the gauge and you’ll see there's a small cock, what is known as the Hopkinson tri cock. These aren't piped away anywhere. On a lot of boilers they were piped away to a drain, but in our case at Bancroft there was no handy drain and they were just piped into a bendy which we used to leave pointing like that. When we wanted to blow the gauges down we just used to turn that pipe round and point it into the coal bunker and allow the dirty water to blow out on to the coal.
The sequence of operations was, and here I should mention that the valves on the Hopkinson water gauges were very special valves, they were asbestos packed cocks. These were packed with a special mixture of finely divided asbestos and rubber known as ‘Indurated Asbestos’. I think it’s illegal now but I still have some. The idea was that you packed the spaces cast in the body of the cock with this fine mixture while the cock itself was in place and then you hammered it in with specially shaped packing tools made to fit the spaces. When the cock was installed and the steam raised it to boiler temperature this cured the mixture and the packing became an integral part of the construction of the cock. This made a very reliable seal which could last many years under normal working conditions. Notice that they were cocks and not valves. You could immediately tell by the position of the valves whether they were open or closed. This is the reason why cocks were fitted to the gauges. Safety depends on it being immediately clear whether the cocks are open or shut. You can walk into any boiler house in the country and see from one look whether the gauges are operating or not.
The sequence of blowing gauges down varied, different people did different things. The way we used to blow them down, the way I always used to blow them down was to first of all swing the drain pipe out till it was pointing out into the bunker. Then close the top cock, and open the small cock at the bottom. This meant there was a passage from the bottom aperture in the boiler plate to atmosphere so a strong jet of superheated water blew through taking any sediment with it. Close the bottom gauge cock and open the top one, this allowed steam to rush down the tube to atmosphere and cleared the top aperture and the glass tube. This was when the tube got eroded. Then close the top cock. Close the tri cock. Open the bottom gauge glass cock very slowly and fill the glass with water. Then open the top gauge cock and allow steam in. The gauge glass will slowly equalise pressure and will give a true reading after about 30 seconds.
You now know that those gauges are telling the truth and can rest easy in your chair.
You can get a lot of information from the gauge glasses apart from the water level. If you see the water level fluctuating in the glass you know that a lot of steam is flashing off. Rather like a rolling boil in a kettle. If you see water running down the glass from the top of the gauge it’s an indication that the boiler might be priming. That is the water has frothed up and is above the level of the top hole in the boiler plate. In other words your water is dirty and you might be getting very near to priming, which in where froth and water and muck goes up the steam pipe into the engine, a dangerous condition.
A very common question that is asked by a boiler surveyor if he doesn’t know the firebeater or the engineer is “What do you do if you can’t see any water in the gauge glasses. The inexperienced bloke will say “Christ we rush down in the cellar and get the feed pumps going straight away." That isn't the right answer, what you do is blow the gauges down because what you’ll probably find is that it wasn’t a question of having no water in the glass, you have got too much. The level has risen beyond the top of the glass and therefore the glass looks as though it's empty. If it's clean water it'll look as though there is no level so the thing to do is to blow it down first, and see what the level settles down to. If the level vanishes out of the bottom of the glass you are low, if it vanishes out at the top you have got water. Gauge glasses are always fixed on the boiler so that if water shows in the bottom of the glass you have 2” over the highest part of the furnace crown which is safe but marginal.
Low water is when the furnace crowns become exposed, they are not cooled by water and become red hot, lose strength and collapse or rupture. That’s when you get boiler explosions. It’s a very dangerous condition. The way to avoid it is always to keep your water at least at working level.
Now, a word about working levels. One of the beauties of the Lancashire boiler is the fact that it holds a lot of water. Some boilers water capacity is limited and they are very free steaming boilers but they have very little reserve. Now a lot of people think that the reserve is something to do with the volume of steam contained above the water level, in the space in the boiler which isn't taken up by water. This is a fallacy. The steam in the space above the water in a Lancashire boiler might run the engine for 30 seconds, if that. Your true steam reserve is in the amount of water that you can afford to lose without endangering the integrity of the boiler.
This needs some explanation. The first thing to realise is that if you lower the pressure on a body of superheated water it has to get rid of heat immediately until it has got down to the correct temperature for the lower pressure. It reacts like champagne when the cork is popped, the excess gas rushes off in strings of bubbles generated in the liquid. Superheated water does the same thing but not because of dissolved gas, it’s because the only way it can lose heat is to generate steam. The next thing to realise is that the white stuff that comes off boiling water isn’t steam. It’s condensed water in very fine droplets. True steam is water raised to a temperature where it becomes a gas.
The speed at which you can take steam off a boiler depends on the rate at which you can burn coal and put heat into that boiler and the reserve of water you have which can flash off into steam as the pressure drops. A brief description of what flashing off means would be useful. If you could get a bucketful of water out of the boiler and keep it under pressure and put it on the boilerhouse floor and then reduce the pressure to atmospheric it would explode like a stick of dynamite as the water expanded to probably 10,000 times its volume instantaneously. This is what happens when a boiler ruptures and is the reason why they are so dangerous.
Suppose you have a bigger demand on the boiler than the coal burning in the furnaces can supply. Boiler pressure starts to fall and when it does it is a controlled version of what happened to our bucket of steam. The water in the boiler starts to flash off and make up the shortfall. The length of time this can be allowed to go on depends on how much water you can afford to lose before the water level over the furnace crowns becomes critical.
Herein lies the Lancashire Boiler’s steaming capacity. If you know you are going to have a heavy demand you get your pressure up but at the same time open the feed pumps up and raise the water level to say an inch from the top of the glass. This means that even though the pressure may fall a little you can carry on generating perhaps 50% more steam than you are putting heat in. Actually there is no such limit because the boiler would make steam as long as there was superheated water in the boiler whether the fire was lit or not. I once ran the weaving shed for over two hours with no fires in. This wasn’t from choice but circumstance and even I was amazed how long it ran for..
So, here we have a clue to the best way to manage a Lancashire boiler. You may remember me saying that I improved the feed pumps at Bancroft and I said I’d come back to the subject. The secret of running a Lancashire boiler most economically depends on having reliable and easily controlled feed water pumps. When I had finished my improvements we had these.
We used to start in the morning with the water an inch down from the top of the gauge glass, about 140psi of steam and a fairly full fire running at say 75% of capacity. If the boiler pressure started to drop, say the tapes were boiling size and using a lot of steam, the trick was to leave the fires alone but cut back on the feedwater and allow the level to drop back. When the pull on the boiler diminished, the feed was opened up again to a level which kept the pressure steady but allowed the water to build again. So we weren’t adjusting for demand with the fires but with the feedwater. This meant that the fires were burning steadily and at their most efficient. If we found out we were getting into trouble with high or low water we adjusted the fires. For low water we speeded the fires and the pumps. For high water we slowed both.
Another factor comes in here which needs addressing. Every 111degrees Fahrenheit you raised the temperature of the feedwater, you gained 1% on the efficiency of your boiler. This is the reason why mill owners spent a lot of money on economisers which were a nest of tubes in the hot flue gases through which feedwater was pumped to the boiler. This extracted heat from the flue gas and transferred it back to the boiler. When new or in good condition the economiser worked under the same pressure as the boiler thus increasing its efficiency even further because you could superheat the water. Our connies at Bancroft failed the test long before I arrived on the scene bit we could still run them at atmospheric pressure. What I used to do was have one pump, the Pearn, pushing water round the economisers and returning it to a hot box in the cellar with a float switch on. When the level reached a certain point the Brown and Pickles pump would kick in and pump the almost boiling water into the boiler. The overall feed was governed by a simple by-[ass pipe between the delivery and the intake on the Pearn. If you shut it the pump delivered maximum flow to the connies. As you cracked that valve open the flow diminished. The Pearn ran constantly and the flow of water to the boiler was controlled by that one small valve. It was a brilliant system and we had perfect control over the feedwater and thence, the output of the boiler.
SCG/23 September 2003
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