Click here to register on OneGuyFromBarlick|2|1
Author Previous Topic Topic Next Topic  
Doc
Keeper of the Scrolls


2010 Posts
Posted -  28/05/2004  :  16:26
LANCASHIRE TEXTILE PROJECT


TAPE 78/AI/08 (Side one)


THIS TAPE HAS BEEN RECORDED ON MAY 1ST 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..





Picture number 32. Negative number 770522.
We start today describing the pictures in the Bancroft Folio again with this picture of the governor at night. It’s taken on a very long exposure, with one point source of light, which means that you get some very interesting reflections from the metal parts of the governor. The halo at the top always amused me, the governor is a bit of a God, it looks after everything and it's almost saint-like. That halo of course is a reflection off the balls at the top of the governor which have faded out completely due to lack of exposure. The only thing that’s being recorded are the reflection of light. I must admit I've put it in because it was just a beautiful picture - but it does say a lot about the governor, it gives an impression of how precise the governor was, how precisely it was manufactured and what its function was. The links are thrown out by the speed, the links which hold the balls have been thrown out by the speed and the governor bar - that's the horizontal bar at the bottom- is horizontal, it's not drooping down, that governor is doing its job.



Picture number 33. Negative number 770516.
This is a picture of the high pressure crank pillow bearing and engine bed again done at night with a very long exposure. When I say at night I mean during the winter when we were running in the dark. This was one of the first films I shot in 1977 from the negative number and so it's going to be during January when of course it gets dark early at night. And what we are getting here is a picture of the engine which normally you couldn’t see with the human eye because even though the engine house was fairly well lit, there wasn't much light in this corner. The long exposure has done two things; it has brought into clarity the dark parts of the engine next to the flywheel which couldn't normally be seen, and it's got rid of the con rod and the crank, because of course they were moving so fast that they hadn’t time to register on the negative. The only thing which was registered are the point reflections of light from the single bulb up on the right hand side on the distributor board. A very interesting picture in many ways, it gives a lot of information. First of all you get a clear idea of the massive construction of the pillow block itself which contains the bearing which carries the flyshaft. If you look behind what looks to be the completely circular boss of the crank, but is of course just the part which was registered on the negative, if you look at nine o'clock on that circle on the flyshaft and crank and follow that into the pillow bearing you'll see a straight line which is the brass, it's the edge of one of the three brasses which actually form the bearing which carry the flyshaft in the pillow bearing. And, there seems to be a white mark down the inside of it, up against the pillow bearing. This is froth. It's a froth of oil caused by the fact that those bearings were moving slightly in the housing all the time. This isn't a faulty it's quite deliberate. You can't have bearings of this size and this nature nipped up until they are tight, you have got to allow some play. Remember that over the years this engine bed has settled and that flyshaft is no longer running dead true in those bearings, it couldn't be expected to, even on the best foundations there will be some alteration over the years.



Very clearly to be seen on the cap of the bearing, you can see the two big holding-down nuts and lock nuts at this side which hold the cap on to the bearing. These in fact on this bearing were tight because the cap didn't touch the shaft when it was nutted right down. Behind those holding-down nuts, the cap holding-down nuts, you can see a threaded rod stuck up with a square top and a lock-nut at the bottom. This was the method of actually adjusting the bearing. That threaded rod is threaded down through the cap and has a plain end at the bottom which bears on a cast iron wedge. The principle of adjustment is that you slacken the lock-nut off and turn the square top of that rod, that forces the threaded rod down which bears on the wedge and forces the wedge which lies between the body of the pillow block and the brass bearing further down in its housing. As it forces it down it pushes the bearing in, towards the shaft. So it’s obvious that the further down you force that wedge the nearer that bearing will be to the shaft, the less play there'll be in it and the tighter that bearing will be on the shaft.



People often ask exactly how we adjusted those bearings, because it's quite obvious, as I have said before, these bearings were of such a size that it wasn’t possible to nut them up tight and then shake the shaft or turn the shaft and see when they came slack. There was far too much weight involved. Here again, what you did was, when you thought one of those bearings needed adjusting, was to do it while the engine was running.



The reason for this is that when the engine was stopped the weight of the shaft will be bearing on one of the brasses, usually the front one because of the weight of the ropes. As this is the one that carries most of the load it is the one that needs adjusting. If you try to drive the wedge down while the weight is on it you won’t get a result because you can’t expect a relatively small thread like this to move 30 odd tons of metal. So you do it while the engine is running and while the bearings are floating. You just give those a fraction of a turn, when I say a fraction, a sixteenth of a turn would be ample for one adjustment on that bearing. And of course you'd do both of them the same, and then you’d let it run, keeping a very careful eye on it. When I say keeping an eye on it, you keep a very careful hand on it. You go to it frequently and put your hand on the case of the pillow blocky and feel what the temperature is. The way you can tell when a bearing is adjusted to its limit is when you get it to the stage when the temperature is beginning to rise slightly. In point of fact you didn't look for that, what you did was just give it a fraction of a turn and then run it for two or three days or even more and see how it was and see if it cured the fault that you had observed in the first place.



The fault usually was that you could see the flyshaft moving slightly or you could see that the bearing was moving slightly when the thrust and counterthrust came on at that side. One general point should be made which applies to all the bearings on the engine. A sensible engineer leaves them alone unless there is a pressing reason for adjusting them. If you think about a comparison between these bearings and the relatively small bearings in say a car engine. Look at the tolerance advised by the automotive engineers and scale that amount of play up for the size of shaft and you will find that the large bearings have proportionately less play than the small ones.



On top of the bearing we have a good view of the aquarium lubricator. You can see two of the three oil taps inside which distribute the oil equally across the bearing. These dripped the oil down into funnels which contained a sieve, and from then on through plain holes right down through the cap so that the oil dropped on to the shaft.



I should point out here that we never had one of these bearings out, but with big plain bearings like this at Bancroft there was no white metal in them, they were just bronze bearing. Note that we called them ‘brasses’ but this was a misnomer, they were never made of brass but of a special bronze which was alloyed to give good lubricating properties. The main ingredient was copper with small additions of tin and lead.



It's essential that you have oil distribution galleries in the bearing. In other words you have got to let the oil into the bearing and once it's in you have got to distribute it across the face of the bearing. This was done by means of grooves cut on the inside of the bearing. One of the things to avoid with bearings like this is sharp edges because they tend to wipe the oil off instead of allowing it to stay on the shaft.



Perhaps the best way to illustrate this is to repeat a story that my father used to tell about an engine at Armstrong Whitworth’s, part of a group of engines, I think they were Willans high speed steam engines, which drove directly on to alternators and provided electric current for Armstrong Whitworth’s works in Manchester. They had a lot of trouble with one of them because the main bearings, the pillow bearings on the crankshaft kept heating up.



It was decided to take this shaft out, re-face the journals, make new oversized bronze and white metal bearings and put them in to cure it. Unfortunately it didn't. In the end they found out that the reason why they hadn't cured it was that they'd made too good a job of the shaft. They turned it down until it was perfectly circular and then put a ground finish on it to wake sure that it was absolutely the right size and perfectly true. Unfortunately they’d put such a good finish on the shaft that there was no room for the oil. The bearing wouldn't hold oil and it was in effect running dry.



The important thing to realise about the lubrication of these bearings is that the oil is not fed in under pressure, it is a gravity feed. In order for this method to be efficient, there has to be enough room in the bearing not only for the oil to get in but to perform its function once it has got there.



The technical term for the method of lubrication used at Bancroft and on most steam engine is ‘hydrodynamic’. This is full lubrication, the oil forms a barrier between the bronze bearing and the shaft so that they never touch. In order for this to occur there has to be enough room between the shaft and the bearing to allow a wedge of oil to build up in front of the shaft and as it tries to squeeze this out, it is channelled by grooves in the bearing surface which allow oil to be carried back under the shaft. It follows that this effect is helped if the shaft has sufficient grip on the oil film to carry it under itself. In addition, the edges of the bearing have to be chamfered so that the oil can get in to form the wedge and isn’t wiped off by the sharp edge.



In the case of the Willans high speed engines at Armstrong Whitworth’s the cure was to file the shaft so as to destroy the too-perfect finish and allow pockets on the shaft to carry oil into the bearing.



Remember that there are three elements to the bearings in this pillow block. One in the bottom and one at each side; the top is open and the oil is dropped on to the top bare side of the shaft. If there is a sharp edge on the bearing at the far side from where we are viewing it now, that will wipe that oil off instead of allowing to go in. And so it was essential that that bearing had quite a large chamfer cut on it and also oil galleries so that it would collect the oil and take it down into the bearing. Inside the bearing was another lateral gallery running right the way across but not actually coming out at the edge of the bearing, which allow a reservoir of oil to build up and be distributed equally across the face of the bearings on the inside. Very, very important the lubrication of these bearings.



The most common cause of temporary stoppage of steam engines was overheating of plain bearings. The usual cause was an oil stoppage or bad adjustment. I never had a ‘hot neck’ at Bancroft but in later years at Ellenroad had a small bearing heat up after an unknown ‘engineer’ decided to take the play out of it. It heated to the point where the bronze was melting in less than ten minutes and it was only a small bearing.



There is an emergency cure for a bearing that has heated up. You allow the bearing to cool down and rectify whatever caused the overheating. What has happened inside the bearing is that the heat has melted the bronze and at the same time has destroyed the oil and allowed the shaft to rub on the bronze. The effect of this is to ‘rope’ the surface of the shaft. In a bad case this looks like corrugations. This is actually no detriment in a very slow moving bearing like a water wheel as long as the profile of the defects in the shaft matches the face of the bearing. A bearing like the Bancroft pillow bearing won’t be as bad as this but will be damaged.



The cure is to introduce a soft abrasive into the bearing and run it. By ‘soft abrasive’ I mean one which is not so hard that the metal of the shaft and the bearing can’t break it down. If it is too hard it embeds in the soft metal of the bearing and will simply stay there and accelerate wear. There was a proprietary powder called ‘Victory Compound’ and every engineer had some about him. This was mixed with oil, fed into the bearing and then washed out with a light spindle oil when it had done its job. The engine could usually be then re-started, run with plenty of oil flow and the oil in the aquarium changed a couple of times to get rid of any residue of the abrasive. Newton Pickles once told me that with water wheels they used to use a soft brick hammered until it was a fine powder. He reckoned that this was the main constituent of Victory Compound.



[It’s worth mentioning here another thing I have learned about bronze bearings by experience. The bronzes used for large bearings, and particularly in my experience the naval bronzes, are relatively plastic at normal temperatures. Over many years service they tend to deform in their housings and spread sideways, almost as though they were being squeezed out of the bearing housings. If you have overheating problems with an old bronze bearing, particularly one which could have been subjected to reciprocating shock loadings, like a cross head, crank pin or pillow bearing, look first to the fit of the shoulder of the bearing in the corner of the journal machined on the shaft or pin. Nine times out of ten this is where the problem will be, the shoulder will be bearing too tightly in the journal and no matter how much play there is in the face of the bearing it will build up heat in the shoulder, expand and run ‘stinking hot’.



At this point, an inexperienced fitter will dismantle the bearing and find unmistakeable signs of the bearing running too tight on the journal. He or she will also note damage on the shoulder of the brasses. They will not realise that the latter came first, expanded the metal and the former occurred as a consequence of the first. They will attack the fit on the face of the journal as the cause, ‘rectify’ that, put it back together and have exactly the same trouble. The cure is to remove a considerable amount off the shoulders. All bearings of this type are manufactured with an adequate amount of side float for this reason. I have never seen one get into trouble with having too much. Indeed, on many applications this side float is essential to good running to absorb movements in the running position of the journal due to other factors. The motion of steam locomotives has to have enough float to accommodate deflections in the running of the wheels due to curves and deformations of the track. Traction engine bearings mounted in the horn plates have to accommodate the same deformations due to running on uneven road surfaces. The flyshaft bearings on a large flywheel have to allow the non-perfectly balanced flywheel to float under the influence of unequal centrifugal forces.]



If you look at the flywheel itself, of course all the detail there has been blurred and all you can see are the circular parts, you'll see the big expanse of boarding itself. If you go in towards the centre of the shaft you'll see the circular marks caused by the actual boss, which was turned circular. Then before it reaches the centre you'll see that it appears that there is a black mark, a black circular mark, it looks like a gap, but of course one would think that there couldn't be a gap there because that flywheel had to be solid on that shaft. In point of fact it is a gap. It is surprising to a lot of modern engineers to see the method of fastening a large flywheel or pulley onto a shaft which was used, in those days. The flyshaft is not circular where it goes through the flywheels or rather it has been turned circular, but it has had four (or more) big flats milled on to it. It is not a ‘plug’ fit in the centre of the flywheel, there is a clearance of perhaps, before the flats were machined in it, a clearance of at least an inch and probably more. The method of fixing the flywheel on to the shaft was by means of four very large, very precisely machined and fitted wedges, known as stakes. Two were put in from one side, and two were put in from the other; and by the degree and the order in which these stakes were driven up the flywheel was set perfectly true on the shaft. I have never seen this done but Newton Pickles tells me that you can do it with a board, a piece of chalk and two men and a big hammer. In actual fact with a flywheel this size they'd very nearly surely be tupped in. When I say tupped in, you'd have a chain hung on the block and at the bottom of the chain you have a large piece of metal suitable shaped on the end that’d probably weigh three or four hundredweight. You just swing it and let it hit the end of the wedge on the way back rather like the old fashioned battering ramp but slightly more scientific. That’d be used for the final tightening.



Also in the centre can be seen two lines running away from the blur of the eccentric sheaves, one above and one below, back towards the governor. These are the governor ropes, three of them, cotton ropes, exactly the same as driving ropes but of course smaller which came off a pulley which sits in between the eccentric sheaves and the flywheel, mounted on the flyshaft. This drove the governor, so this meant that the speed, assuming that the ropes were gripping the pulleys, the speed of the governor varied directly with the speed of the flyshaft which of course gave the governing effect, gave the power for the governor to work.



If you look through the blur of the crank, above the flyshaft you'll see the cover of the slide valve on the nearest cylinder of the barring engine held on by ten nuts. On top of it you'll see the brass lubricator and that's about all the detail you can see of the

barring engine itself.



The action of the banjo-oiler is clearly seen here. The banjo is quite obviously in line with the centre shaft as its motion relative to the shaft is zero, it's just moving in a circular motion and the drip feed lubricator mounted on the rail is dripping oil directly into the banjo and it's being thrown out to the crankpin bearing from where it flies

off and hits the splash tray behind. You can see the oil running down the splash tray, you can see that it's oiled up. On the engine bed near the stanchion in the right-hand corner you'll see a very thin piece of wire just beyond the oil kettle. That piece of wire was there for use if there was a blockage in the drip feed lubricator, usually a thread of cotton waste. You could screw the adjusting needle out of the lubricator and clear the blockage with the wire.



Then there is the little tea pot which was solid brass. As I've said before this was a present to my mother and father and finished up being relegated to duties on the engine. It contained the reserve of oil for the drip feed lubricator. It was also used when starting or if the lubricator was blocked to pour oil straight into the banjo to lubricate the crank pin until the regular flow started from the drip feed oiler.



Next there is a pair of gland nut pliers which were used to slacken off the adjustment on the lubricator if that needed altering. They very often did need altering because one of the faults of a drip feed lubricator is that as the temperature rises and the oil thins down they run a lot faster, it makes a big difference to them. Very often we used to start them off in the morning with the engine cold and we’d have to open them up a bit to get the right feed, the feed we wanted. As they warmed up we’d cut them back a bit. The lubricator has a sight glass at the bottom and I always used to reckon on about one drip every four revolutions for the high pressure side; if things were running exceptionally well five revolutions, if things weren't doing well perhaps a bit more, every three revolutions, or even two. The idea was to get a cushion of oil in the crankpin bearing because in common with all the other bearings, this bearing wasn't tight, it always had a slight amount of play in it. We used to have a saying that it was far better to hear them then smell them, in other words it was far better for a bearing to be slightly slack and knocking a bit than tight and overheating and burning the oil. You could smell the oil, of course that was serious, the engine had to be stopped straight away.



Notice the high polish on the rails. Everything that can be polished is polished and painted up, as I've said before we used to look after them. Tin tray in the bottom of the crankpit which catches the oil and returns it to the cellar. This is padded with waste round the sides to catch any excess oil and stop it going under the beds. In point of fact it was too late with this bed, oil had got underneath it and this bed was slightly loose. In the extreme bottom right-hand corner of the picture can be seen the trough on the side of the engine bed with the rope in it made of cotton waste to fulfil the same purpose on the outside.



Notice again the glazed bricks that we used for the first 5ft of the brickwork all the way around the engine house, very easy to keep clean, and a nice pleasing colour, they were cream and a very reddish brown at the bottom, all of them glazed up to about 5ft and from then on plain Accrington brick. [When I was working on Ellenroad engine I found out that these brown glazed bricks manufactured before WW! Have to be treated with caution. The brown pigment used to colour them is an oxide of uranium and they are radio-active. They are not dangerous unless cut with an abrasive saw and the dust is inhaled.]



One further point about the flywheel boss which is not evident from the picture. The boss of the flywheel which carries the spokes and bears the stresses of being staked on to the shaft is made of cast iron. It was possible to get flywheel bosses cast with impure cast iron where patches of them were what we called ‘spongy’. They were full of tiny gas bubbles frozen into the casting as it cooled. If a keyway was cut through an area like this it could work loose and give trouble. In addition, cast iron is very weak in tension so the boss of the flywheel was strengthened by shrinking a forged steel ring on the periphery of the boss on each side in exactly the same way that a crank was shrunk on a shaft. This ensured that the boss could withstand the bursting pressure of the stakes being driven in to secure it on the shaft.



Picture number 34. Negative number 767642
This is a picture of the High Pressure side from the doorway in the top end of the house which led into the warehouse. One small point about this door. It was always bolted securely during the night and sometimes during the day as well. If I was doing anything that needed total concentration I would lock myself in so that I couldn’t be distracted by anyone. This sound extreme but is necessary when you are dealing with something on the engine whilst it is running.



Notice the boarding in the engine house roof. This was to help stop condensation in the roof in winter. The construction of the roof is steel trusses, wooden purlins and joists with blue slate on the outside. The slates had evidently been clashed up on the underside with lime sand mortar because over the years it had deteriorated and if there was a strong wind a fine dust of sand and lime would fall on the engine. This was bad for the slides and I always kept an eye on it.



The flywheel can be seen clearly with the ropes swinging away from the grooves in a smooth arc up to the second motion pulley. Notice that some ropes have more tension than others. This is a product of age, the quality of the ropes and the skill of the individual splicer who fitted them. Splicing large ropes like this is not an exact science. The amount they would stretch when in use was variable and the splicer had to use his experience to gauge how much initial tension to put on them.



Picture number 35. Negative number 760636.
This is virtually a repeat of picture 34. Daniel Meadows and I competed with each other for the best rope picture and this was my favourite. It gives a very good impression of the movement and the power going up these ropes into the mill, its life force.



Also evident are the large stone lintels over the side windows and the beautifully cut stones of the large arched window in the end of the house. The construction was brick on the inside but coursed rubble faced stone outside, all quarried on Tubber Hill.



Picture number 36. Negative number 774022. Picture 37, negative number 772035. Picture 38, negative number 777514.


Picture 36. This picture shows the garage on the right which used to house the mill’s two motor wagons, the end of the engine house and of course the chimney. I have to confess that we shut the dampers for a couple of minutes while I did this picture so we got black smoke. Normally we never made smoke this dense but in the old days this volume of smoke would be common. The old engineers thought that you couldn’t make steam without smoke. A lot of them also had a superstition which had no foundation in fact, that a chimney drew better if a cast iron bar was laid across the top of it. Bancroft had such a bar on it and we removed it the first time I had it laddered. The origin of this is the fact that locomotive engineers knew that if an engine wasn’t drawing well due to a defective or badly designed blast pipe they could improve it by fitting a ‘jimmy’ which was a splitter on the blast pipe which increased the draught and made it easier to keep a working head of steam. It also increased coal consumption and was frowned on by the management. I believe that at some time an engineer at a mill heard about this practice, didn’t fully understand it but thought he would try it.



Picture 38. The chimney is 130 feet high and is built using special chimney bricks which are shaped to produce a circular structure. There are two types, ‘stretchers’ which have a curved shape longitudinally and ‘headers’ which are wedge shaped with a curved face and a convex face on the narrow end. There are iron bands on the chimney to strengthen it. I have never seen a picture of the chimney as built but do not think these bands are original. The story I have heard is that there was an earth tremor in the early fifties and the insurance companies insisted on many chimneys being banded as a precaution. These are wrought iron bands and are fitted by having turned up ends with holes in them and large bolts nipping them on to the chimney. There should always be a gap between these ends so that as corrosion builds behind the bands the tension generated in the band can dissipate by bending the turned up ends and not crushing the brickwork. If you know what you are looking for you can gauge the amount of corrosion behind the bands simply by looking at the angle of the bend on the ends of the bands.



At the base of the chimney is the boiler house and if you look carefully you will see the end of the stockpile of coal we kept up the yard. We used to keep 200 tons in stock in case there was a transport or coal strike. The largest amount I have ever seen booked for stock at Bancroft was 700 tons or about 20 weeks supply in winter.



The chimney was buttress construction. This means that there were two skins, an inner wall and an outer with internal buttresses for about the first 40 feet of the chimney. Above that it is solid. You can always tell a buttress chimney because they have air bricks in the lower part to allow air to circulate through the cavity. The first 30 feet of the chimney interior is lined with firebrick to protect the chimney from the hottest flue gas in the chimney base. You’ll notice some streaks perhaps on the exterior surface of the chimney. This is double boiled linseed oil which is painted on the outside of the stack to protect the bricks and pointing from the weather. This should be done every five years but Bancroft got no treatment whilst I was there, the firm ‘couldn’t afford it’.



Picture 39. Negative number 776732.
This picture was taken when the boiler was being blown down to empty it for annual maintenance in the summer holidays. Theoretically this is a very bad thing to do to a boiler but we had to get rid of the steam, open the boiler and flues up and let it cool down overnight sufficiently to allow the fluers to get in to do their job. We’ll talk more about the boiler later.



Pictures no 40 and 41. Negatives 789512 and 777520.
These are two pictures inside the weaving shed. The reason I've put these in at this point is to show there the power was going to. Very complicated pictures with a tremendous amount of information in them. On picture 41 you'll see the cross shaft which went across the mill, held in individual brackets on the pillars or the roof girders and running in brass bearings. This shaft was driven by a bevel gear on the lineshaft from the engine which was attached to the North wall of the shed. It carried the pulleys which drove the looms. Bancroft weaving shed was completely belt-driven, this is one of the things which made it such an amazing place in 1978. I don't know anywhere else where you could go into a shed of that size, and see a power lay-out of this description still in its original condition. Absolutely typical of the later methods of building sheds. Cast iron pillars, girder construction, the girder is the gutter in between each valley of the north lights. We are not looking at the windows here, we are looking at the plaster on the reverse of the north light. In other words we are looking south. Bancroft Shed was a true north light shed. You'll find that this isn't always the case because many a time when they were building sheds, especially in towns where space was limited, they weren't always able to lay out the shed exactly as they wished. In the case of Bancroft they did it just exactly right. There are tie rods in between the girders gutters on the line of the pillars. These gutters weighed about 1cwt to the foot and together with the pillars were the most lucrative source of scrap when these sheds were demolished.



Picture 42. negative number 769119.
This is a picture of one of the looms at the back of the shed. I shall talk about looms later but this was put in to illustrate the fact that at night, when the engine was not running, there were only a few pilot lights in the shed to help you find your way round. In the depth of winter these were the conditions the weavers had to prepare their looms under before the engine started and the alternator powered the main lighting. In passing, notice the weft tins on the floor and the small buffet for the weaver to sit on if she had a moment to spare. You can also see the terrible state of the floor, but more of these things later.



Picture number 43. Negative number 777630.
This is simply a picture of one of the engine sop buttons in the shed. Notice the small hammer hung down the side of it for breaking the glass. It was quite common for the glasses to be broken on the fire alarm buttons but I never had an engine stop glass broken. A good job actually as we only had a couple of spares.



Picture number 44. No negative number. Pic by Charlie Meecham.


Picture number 44 is not one of my pictures obviously because I am on it. This is a picture done by a friend of mine called Charlie Meecham from Hebden Bridge, and is of exceptionally fine quality because it was done with a 5X4 plate camera. Really beautiful detail and probably the best way to take photographs in a place like an engine house, but the trouble is that it's very expensive, very slow and you don't get the number of shots done that you want to do to show all the detail. Very good detail down the high pressure side, you can see thy governor ropes clearly on the inside of the eccentric sheaves, you can see the eccentric rods running up towards the rocking blocks, the fish tank lubricator, the con rod, piston rod and cross head on the high pressure side blurred because of the exposure.



I'm just stopping the engine I should say at that time. The reason I say that is because from the position of the balls on the governor the engine's running on speed and yet from the position of the spindle in the middle of the hand wheel of the stop valve which I'm turning, it's almost shut. It wouldn't be running at that speed if I was starting it. So I would say that I was just stopping that engine at dinner time. We can't see the clock, we can't see what the time is but I should say that I’m just stopping that engine at dinner time. It brings back a lot of happy memories that picture. I enjoyed myself running that engine.



Picture number 45. Negative number 787309A
This is a picture in the cellar. On the left is the engine bed and in front of you is the jet condenser. Now this is the place where the vacuum was developed for the low pressure cylinder. The large pipe in the top of the picture going down into the top of the jet condenser is the exhaust pipe from the low pressure cylinder. On the right of the condenser can be seen a valve with a rod going up into the engine house. This is the inlet valve for the condenser water from the lodge and it was controlled by a lever up in the engine house. The vertical pipe under the valve leads directly to the foot valve and strainer in the lodge. The air pump on the left of the condenser, was sucking water out of the dam through that pipe, through the condenser, and thence out

to ran back to the dam as waste. As the water came in through the large valve on the right it entered a large annular ring on the conical body of the condenser at the top and from there was distributed as a spray into the condenser through a series of holes. This gave a very fine broken up spray of water inside the condenser which instantly

condensed any hot steam coming in from the engine. All that was left to go out through the bottom was the condensate, the condenser water and entrained

air which had come in with the steam and through leaks in the engine. This is the reason why these pumps were always called ‘air pumps’. In point of fact they were pumping water; because there was always leakage and you did get a lot of air entrained in the water that was going out of the condenser.



The smaller pipe coming out of the condenser low down is the connection to the vacuum gauge on the engine. The larger pipe above it which goes into the annular ring was a water supply from the mains which could be used under conditions of drought or very hot water in the dam to put cold water into the condenser. I did occasionally have to use that but in point of fact it wasn’t a great deal of use because if the water in the dam was low or hot, the water in the mains was usually at a fairly high temperature as well. And anyway it wasn’t really a big enough supply to make any appreciable difference.



Picture number 46. Negative number 787228.
This is the air pump itself and is taken on the opposite side of the engine bed which was on the left in the previous picture. You can see the condenser behind the pump and the exhaust pipe from the LP cylinder. The linkage above is the bell crank which is driven off the low pressure tail slide. The two big brackets you can see hanging down, one at each side, carry the bearings on which the bell-crank is mounted and of course the far end of the bell crank is driving the rod up and down in the pump. The piston rod of the pump is the centre rod going into the pump. The two side rods are stay rods attached to the pump casting at the bottom and the engine bed casting at the top.



The action was that the piston or more correctly, the bucket, was cast iron pierced with holes all over and on top of each of these holes was mounted a piece of rubber which acted as a clack valve. These were located and supported by cast iron saucers. These allowed water through the bucket on the down stroke but closed as the bucket moved upwards. This meant that when it was running the pump was always drawing water out of the condenser and hence applying a suction on the pipe from the dam as well. In the top of the main casting of the pump was a large cast iron plate with a gland in the middle through which the bucket rod passed. This ‘delivery plate’ was also pierced and fitted with rubber clack valve located and supported by saucers which allowed water to pass out of the body of the pump to overflow back to the dam when the bucket was rising. Both the condenser and the pump body were mounted on a hollow cast iron box called the ‘coffin bottom’, so called because it tapered at both ends and looked a bit like a coffin. Both the condenser and the pump were open at the bottom and so they connected with the coffin bottom. Between the condenser and the pump in the coffin bottom there was a cast iron grid covered on the pump side by a large rubber flap valve. This would allow the pump to pull water out of the condenser but would not allow any to be drawn back through by the vacuum in the condenser.



There was also a non-return valve in the inlet pipe in the dam. The effect of these two valves was to ensure that when the engine was stopped the pipe from the dam maintained its water level and was always full.



Notice that there are two large square boxes on the side of the pump body casting. These were an idea of Roberts whereby they were going to form an air cushion and stop hammering in the pump which is always the big failure of air pumps. In point of fact it never worked and this was always a lousy air pump. You will notice two pipes with taps on top. These were snifting valves and the idea was that by bleeding air into the bottom of the pump using the vacuum in there, you could entrain more air in the water in the body of the pump and get even more cushioning of the large masses of water moving round in the pump body. These never did any good on this pump and we never had a good vacuum.



Johnny Pickles recommended in 1935 that an Edwards air pump should be fitted but this was never done. It’s a shame because the Edwards is the best reciprocating air pump there is and would have given us a lot more vacuum and a lot less trouble.





SCG/18 September 2003

7,356 words.

Back to Stanley Graham's Page


Set us as your default homepage Bookmark us Privacy   Copyright © 2004-2011 www.oneguyfrombarlick.co.uk All Rights Reserved. Design by: Frost SkyPortal.net Go To Top Of Page

Page load time - 0.406