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50-446: The two distinguishing features of Franklin's stove were a hollow baffle (a metal panel that directed the flow of the fire's fumes) and a flue that acted as an upside-down siphon . Baffles were used to lengthen the path that either a room's air or a fire's fumes had to flow through ductwork, thereby allowing more heat to be transferred to the room's air temperatures or from the fire's fumes. Specifically, ducts could be installed within

100-557: A Thomas Frye painting, also apparently lost, which showed the subject as an old man in 1743. An engraving by Etienne-Jehandier Desrochers was almost certainly made in 1735 when Desaguliers was on his only visit to Paris. There is also an oil attributed to Jonathan Richardson. Desaguliers wrote on many topics for the Philosophical Transactions of the Royal Society , produced several editions of notes for

150-503: A Freemason in 1731, and he additionally became a chaplain to the Prince. On 14 October 1712, John Theophilus Desaguliers married Joanna Pudsey, daughter of William and Anne Pudsey of Kidlington, near Oxford. For most of their married life, the couple lived at Channel Row, Westminster where Desaguliers gave the majority of his lectures. When forced to leave due to work on Westminster Bridge, they separated and John Theophilus took lodgings at

200-480: A chimney. Shortly after starting a fire in the bowl, hot air would begin to rise through the pipe and then up the chimney; this created a downward draft through the bowl, which drew the fire and its fumes down into the bowl. Once the draft was initiated, it was self-sustaining as long as the fire burned. Dalesme's stove could burn wood, incense, and even "coal steept in cats-piss" yet produce very little smoke or smell. These results showed that fires could be used inside

250-454: A duct near the fire, which heated the room's air via convection. Some early experimenters reasoned that if a fire in a fireplace were connected by a U-shaped duct to the chimney, the hot gases ascending through the chimney would draw the fire's smoke and fumes first downwards through one leg of the U and then upwards through the other leg and the chimney. This was what Franklin called an "aerial syphon" or "syphon revers'd". This inverted siphon

300-407: A few inches away from the flue (chimney). On the bottom panel there were several holes to allow the smoke to escape; these were connected to the chimney. The panels were bolted together with iron screws through pre-cast ears. Inside there was a small, thin rectangular prism that would force the smoke into the holes. The plates were all made from iron. Franklin's stove sold poorly. The problem lay with

350-439: A flow of liquid or gas. It is used in some household stoves and in some industrial process vessels (tanks), such as shell and tube heat exchangers , chemical reactors , and static mixers . Baffles are an integral part of the shell and tube heat exchanger design. A baffle is designed to support tube bundles and direct the flow of fluids for maximum efficiency. Baffle design and tolerances for heat exchangers are discussed in

400-432: A guinea, and without a grave. These are taken from a long poem entitled "The Vanity of Human Enjoyment" (1749) in which the poet attempted to draw attention to the general lack of funding for men of science and not Desaguliers in particular. There are two known engravings, by Peter Pelham and by James Tookey, taken from a lost portrait of Desaguliers painted in about 1725 by Hans Hysing , and an engraving by R. Scaddon of

450-404: A household stoves like Handölkassetten and similar stoves a baffle is used to prevent the gas from going directly up in the chimney and possibly causing a chimney fire and direct the gas towards the front of the oven before it continues upwards into the chimney. In this case the baffle helps increase the efficiency of the stove as more heat leaves the gas before it exits. Implementation of baffles

500-530: A machine to explain tidal motion. In 1717, Desaguliers lodged at Hampton Court and lectured in French to King George I and his family. In 1714, Isaac Newton , President of the Royal Society, invited Desaguliers to replace Francis Hauksbee (1660–1713) as demonstrator at the Society's weekly meetings; he was soon thereafter made a Fellow of the Royal Society. Desaguliers promoted Newton's ideas and maintained

550-421: A room, without filling the house with smoke. Franklin's stove contained a baffle directly behind the fire, which forced the fire's fumes to flow downward before they reached the chimney. This required a U-shaped duct in the floor behind the stove, so that the fumes could flow from the stove into the chimney. Thus Franklin's stove incorporated an inverted siphon. Gauger's book on his innovative fireplace designs

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600-573: A room. Many others improved on the Franklin stove design, but to this day, most American fireplaces are box-shaped, similar to the Franklin stove. The exception is the Rumford fireplace , developed by Benjamin Thompson. The stove was about 30 inches (76 cm) tall, with a box shape. The front was open, except for a decorative panel in the upper part of the box. The back of the box was to be placed

650-570: A stove that could provide more heat with less smoke. In 1742, Franklin finished his first design which implemented new scientific concepts about heat which had been developed by the Dutch physician Herman Boerhaave (1668–1738), a proponent of Isaac Newton's ideas. He supplied his equipment from a local iron pioneer William Branson from Reading, PA. Franklin wanted his stoves to be available to everyone, relishing popular appreciation of his handiwork and eschewing patents . This combination of events led to

700-404: Is decided on the basis of size, cost and their ability to lend support to the tube bundles and direct flow: As mentioned, baffles deal with the concern of support and fluid direction in heat exchangers. In this way it is vital that they are spaced correctly at installation. The minimum baffle spacing is the greater of 50.8 mm or one fifth of the inner shell diameter. The maximum baffle spacing

750-496: Is dependent on material and size of tubes. The Tubular Exchanger Manufacturers Association sets out guidelines. There are also segments with a "no tubes in window" design that affects the acceptable spacing within the design. An important design consideration is that no recirculation zones or dead spots form – both of which are counterproductive to effective heat transfer. John Theophilus Desaguliers John Theophilus Desaguliers FRS (12 March 1683 – 29 February 1744)

800-662: Is remembered as being instrumental in its early success. He became the third Grand Master in 1719 and was later three times Deputy Grand Master. He helped James Anderson draw up the rules in the "Constitutions of the Freemasons", published in 1723, and he was active in the establishment of masonic charity. During a lecture trip to the Netherlands in 1731, Desaguliers initiated into Freemasonry Francis, Duke of Lorraine (1708–65) who later became Holy Roman Emperor . Desaguliers also presided when Frederick, Prince of Wales became

850-625: The Bedford Coffee House in Covent Garden and carried on his lectures there. The Desaguliers had four sons and three daughters, for most of whom they acquired aristocratic godparents, but only two children survived beyond infancy: John Theophilus jnr (1718–1751) graduated from Oxford, became a clergyman, and died childless, while Thomas (1721–1780) had a distinguished military career in the Royal Artillery , rising to

900-570: The Desaguliers' home. Desaguliers's "Dissertation concerning Electricity" (1742), in which he coined the terms conductor and insulator, was awarded a gold medal by the Bordeaux Academy of Sciences. James Brydges, 1st Duke of Chandos appointed Desaguliers as his chaplain in 1716, but probably as much for his scientific expertise as his ecclesiastic duties. He was also gifted the living of St Lawrence Church , Little Stanmore, which

950-826: The Royal Fireworks in Green Park. He later became an equerry to King George III. John Theophilus Desaguliers had long suffered from gout . He died at his lodgings in the Bedford Coffee House on 29 February 1744 and was buried on 6 March 1744 in a prestigious location within the Savoy Chapel in London. The chapel was probably chosen for its Huguenot associations and in memory of Desaguliers's origins. The press announcements of his death referred to him as 'a gentleman universally known and esteemed'. In his will Desaguliers left his estate to his elder son who organised

1000-816: The baby was baptised Jean Théophile Desaguliers in the Protestant Temple in La Rochelle, and he and his mother then escaped to join Jean in Guernsey. In 1692, the family moved to London where Jean Desaguliers later set up a French school in Islington. He died in 1699. His son, who now used the anglicised name John Theophilus, attended Bishop Vesey's Grammar School in Sutton Coldfield until 1705 when he entered Christ Church, Oxford and followed

1050-449: The baffle before exiting to the chimney. The intention was to extract as much heat as possible from the fumes by extending the path that the fumes had to follow before they reached the chimney. The 1678 fireplace of Prince Rupert (1619–1682) also included an inverted siphon. Rupert placed a hanging iron door between the fire grate and the chimney. In order to exit through the chimney, the fire's fumes and smoke first had to descend below

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1100-474: The blowing wheel which removed stale air from the House of Commons for many years. Desaguliers studied the movements made by the human body when working as a machine. He befriended the strong man, Thomas Topham , and although there is no firm evidence that he used Topham as a body guard, Desaguliers recorded several of the feats that he performed. Desaguliers was a parliamentary adviser to the board concerned with

1150-401: The brickwork around a hearth; cool room air would then enter the lower end of a duct, be heated by the hot walls of the duct, rise, and finally exit from the duct's upper end, and return to the room. The longer the path through which the air flowed, the more heat would be transferred from the fire to the air. Similarly, the longer the duct through which a fire's fumes had to flow before reaching

1200-417: The chimney, the more heat would be transferred from the fumes to the room's air. The use of baffles to extract more heat from a fire and its fumes was not new. In 1618, Franz Kessler (c. 1580–1650) of Frankfurt-am-Main, Germany published Holzsparkunst ( The Art of Saving Wood ), featuring a stove in which the fumes from a fire were forced to snake through five chambers, one above the other, before entering

1250-466: The chimney. Kessler also documented an enclosed heating stove that, like Franklin's stove, had a baffle directly behind the fire, thereby lengthening the path that the fire's fumes had to travel before reaching the chimney. In 1624, a French physician, Louis Savot (1579–1640), described a fireplace that he had built in the Louvre . Ducts passed under, behind, and above the fire in the hearth. Cool air in

1300-469: The dead but this was attributed to the curate who was left in charge of the church. Desaguliers applied his knowledge to practical applications. As well as his interest in steam engines and hydraulic engineering (in 1721 he cured a problem in the Edinburgh city water supply ) he developed expertise in ventilation. He devised a more efficient fireplace which was used in the House of Lords and also invented

1350-403: The edge of the door before rising through the chimney. Another early example of an inverted siphon was a stove that was exhibited in 1686 at the annual Foire Saint-Germain, Paris . Its inventor, André Dalesme (1643–1727), called it a smokeless stove ( furnus acapnos ). The stove consisted of an iron bowl in which the fuel was burned. A pipe extended from the bowl's bottom and then upwards into

1400-520: The first Westminster Bridge . This much-needed second crossing of the Thames was not completed until 1750, after his death, but construction work resulted in the demolition of Desaguliers's home in Channel Row. Desaguliers also made significant contributions to the field of tribology . He was the first to recognise the possible role of adhesion in the friction process. For this contribution, he

1450-463: The first Franklin stoves being manufactured by Reading furnaces , which was owned by the local Van Leer family . Two years later, Franklin wrote a pamphlet describing his design and how it operated in order to sell his product. Around this time, the deputy governor of Pennsylvania, George Thomas, made an offer to Franklin to patent his design, but Franklin never patented any of his designs and inventions. He believed "that as we enjoy great advantages from

1500-415: The fumes flowing over the front and back of the box. The warmed air then rose inside the baffle and exited through the holes in the baffle's sides. Franklin's baffle thus performed at least two functions: like Kessler's heating stove, it lengthened the path that the fire's fumes had to follow before reaching the chimney, allowing more heat to be extracted from the fumes; and like Gauger's fireplace, it placed

1550-473: The hero Acis is turned into a fountain, and since, by tradition, the work was first performed outside on the terraces overlooking the garden, a connection with Desaguliers' new water works seems probable. Desaguliers advised the Duke of Chandos on many projects and appears to have been distracted from his parochial duties by his other interests. The Duke once complained that there were unreasonable delays in burying

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1600-483: The honorary degree of Doctor of Civil Laws , after which he was often referred to as Dr Desaguliers. His doctorate was incorporated by Cambridge University in 1726. Desaguliers was ordained as a deacon in 1710, at Fulham Palace , and as a priest in 1717, at Ely Palace in London. In 1712, Desaguliers moved back to London and advertised courses of public lectures in Experimental Philosophy. He

1650-419: The inventions of others, we should be glad of an opportunity to serve others by any invention of ours, and this we should do freely and generously". As a result, many others were able to use Franklin's design and improve it. Although his stove was intended to have the double purpose of cooking and heating a room, as time progressed and new stove designs became available, the Franklin stove's main use became to heat

1700-432: The inverted siphon: the smoke had to pass through a cold flue (which was set in the floor) before the smoke could enter the chimney; consequently, the smoke cooled too much and the stove did not have a good draft. The inverted siphon would operate properly only if the fire burned constantly, so that the temperature in the flue was high enough to produce a draft. A later version, designed by David Rittenhouse , solved many of

1750-538: The problems Franklin's original stove had, and became popular. Franklin's fame outweighed Rittenhouse's, though, so history remembers the Franklin Stove rather than the Rittenhouse Stove. The smaller Latrobe stove , often referred to as a Baltimore Heater, was patented in 1846 and became popular. Baffle (in vessel) Baffles are flow-directing or obstructing vanes or panels used to direct

1800-409: The publication of the second edition of his "Course of Experimental Philosophy". Although never a wealthy man, he did not die in poverty as suggested by the oft-quoted but inaccurate lines of the poet James Cawthorn : How poor neglected Desaguiliers fell! How he who taught two gracious kings to view All Boyle ennobled, and all Bacon knew, Died in a cell, without a friend to save, Without

1850-520: The rank of General. He became chief firemaster at the Arsenal, Woolwich, and seems to have been the first to be employed by the English army to apply scientific principles to the production of cannon and the powers of gunnery, for which he was elected a Fellow of the Royal Society. It was Thomas Desaguliers who in part designed and supervised the fireworks for the first performance of Handel's Music for

1900-431: The room entered the lower opening of a duct, was warmed, rose, and returned to the room through the duct's upper opening. In 1713, Frenchman Nicolas Gauger (c. 1680–1730) published a book, La Mécanique du Feu (The Mechanics of Fire), in which he presented novel designs for fireplaces. Gauger surrounded the hearth with hollow spaces. Inside these spaces were baffles. Cool room air entered the spaces through lower openings,

1950-502: The scientific nature of the meetings when Hans Sloane took over the Presidency after Newton died in 1727. Desaguliers contributed over 60 articles to the Philosophical Transactions of the Royal Society . He received the Society's prestigious Copley Medal in 1734, 1736 and 1741. The last award was for his summary of knowledge to date on the phenomenon of electricity. He had worked on this with Stephen Gray , who at one time lodged at

2000-567: The standards of the Tubular Exchanger Manufacturers Association (TEMA). The main roles of a baffle in a shell and tube heat exchanger are to: In a static mixer, baffles are used to minimize the tangential component of velocity which causes vortex formation, and thus promotes mixing . In a chemical reactor, baffles are often attached to the interior walls to promote mixing and thus increase heat transfer and possibly chemical reaction rates . In

2050-409: The usual classical curriculum and graduated BA in 1709. He also attended lectures by John Keill , who used innovative demonstrations to illustrate difficult concepts of Newtonian natural philosophy. When Keill left Oxford in 1709 Desaguliers continued giving the lectures at Hart Hall, the forerunner of Hertford College, Oxford . He obtained a master's degree there in 1712. In 1719, Oxford granted him

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2100-463: Was a French-born British natural philosopher, clergyman, engineer and freemason who was elected to the Royal Society in 1714 as experimental assistant to Isaac Newton . He had studied at Oxford and later popularized Newtonian theories and their practical applications in public lectures. Desaguliers's most important patron was James Brydges, 1st Duke of Chandos . As a Freemason, Desaguliers

2150-545: Was applied to the elaborate water garden there. He was also technical adviser to an enterprise in which Chandos had invested, the York Buildings Company , which used steam-power to extract water from the Thames. In 1718, Desaguliers dedicated to the Duke his translation of Edme Mariotte 's treatise on the motion of water. It is perhaps no coincidence that in the summer of 1718 Handel composed his opera Acis and Galatea for performance at Cannons. In this work

2200-465: Was close to the Duke's mansion called Cannons , then under construction at nearby Edgware. The church was rebuilt in the baroque style in 1715. As the chapel at Cannons was not completed until 1720, the church was the location of first performances of the so-called Chandos Anthems by George Frideric Handel who was, in 1717/18, like Desaguliers, a member of the Duke's household. The Cannons estate benefited from Desaguliers' scientific expertise which

2250-470: Was instrumental in the success of the first Grand Lodge in London in the early 1720s and served as its third Grand Master. Desaguliers was born in La Rochelle , several months after his father Jean Desaguliers, a Protestant minister, had been exiled as a Huguenot by the French government. Jean Desaguliers was ordained as an Anglican by Bishop Henry Compton of London , and sent to Guernsey. Meanwhile,

2300-727: Was named by Duncan Dowson as one of the 23 "Men of Tribology". Desaguliers was a member of the lodge which met at the Rummer & Grapes Tavern in Channel Row, Westminster, although that lodge later moved to the Horn Tavern in New Palace Yard. According to Rev. James Anderson, this lodge joined with three other lodges on 24 June 1717 to form what would become the Premier Grand Lodge of England . The new grand lodge grew rapidly as more lodges joined, and Desaguliers

2350-420: Was not the first to do this, but became the most successful, offering to speak in English, French or Latin. By the time of his death, he had given over 140 courses of some 20 lectures each on mechanics, hydrostatics, pneumatics, optics and astronomy. He kept his lectures up to date, published notes for his auditors, and designed his own apparatus, including a renowned planetarium to demonstrate the solar system, and

2400-465: Was translated into English – Fires Improv'd: Being a New Method of Building Chimneys, So as to Prevent their Smoaking (1715) – by a French immigrant to England, Jean Théophile Desaguliers (1683–1744). In a postscript to Desaguliers' book A Course in Experimental Philosophy (1744), Desaguliers again briefly described Gauger's fireplaces and mentioned his own work on the subject. Franklin read both of Desaguliers' books and developed his own designs for

2450-404: Was used to draw the fire's hot fumes up the front and down the back of the Franklin stove's hollow baffle, in order to extract as much heat as possible from the fumes. The earliest known example of such an inverted siphon was the 1618 fireplace of Franz Kessler. The fire burned in a ceramic box. Inside the box and behind the fire was a baffle. The baffle forced the fire's fumes to descend behind

2500-409: Was warmed as it snaked around the baffles in the spaces, and returned to the room through upper openings. In Franklin's stove, a hollow baffle was positioned inside and near the rear of the stove. The baffle was a wide but thin cast-iron box, which was open to the room's air at its bottom and two holes on its sides, near its top. Air entered the bottom of the box and was heated both by the fire and by

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