Proceedings.] ETC.ELECTIONS, 211 Associate Members-contiuued. FRANCISBRAGG DRAKE. PATRICKJOSEPH PRENDERGAST. JOHXALFRED EDMONDSON. EDWARDYELF RADLEY, B.A. FRANKGARRETT, Jun., Stud. Inst. C.E. JOSEPHPETER ROBINSON, Stud. Inst. THOXASSTEPHEN GILBERT, B.E.,Stud. C.E. Inst. C.E. JAMESMCKEAN ROWBOTHAI. FRANCISEDTARD HAXOXD, Stud. Inst. ROBERTJOHN SCOTT-BUSHE. C.E. SAMUEL NATHANIEL SQL~RE. WILLIAP HARKER. ALFREDSTILL, Stud. Inst. C.E. STANLEY ARTHURLANE. WILLIAM TOWER. HAROLD MACABDREW, A.R.S.U. HENRYARTHWR DOCGLAS WATHEN. THOXASIVOR MOORE. STEPHEN WATHINI. WILLIADIGEORGE PERROTT,B.E. WiLLIAM SMART \FTELTON, Stud. InSt. FREDERIKBENEDIIIT PETERSEN. C.E. ROBERTEDWARD PRILLIPS. ARTHUR JOHNWILLIA~IIS,Stud. Inst. C.E (Paper No. 2859.) ‘<The Mechanical and Electrical Regulation .of Steam-Engines.” By JOHN RICH&DSON,M. Inst. C.E. ALTHOUGHthe subject of governing steam-engines has occupied theattention of engineers for more than a century, it is still imperfectly understood by users of steam. In spite of thefact that many excellent means of automatically governing the speed of an engine are known, it is not uncommon for a large and im- portant engine to be without any reliable governor, and to depend entirely upon regulation by hand-the governor with which it is fitted being regarded merely as an indicator of the varying speed, to warn the driver toopen or close the stop-valve. The great speed and delicacy of many of the machines used in the textile and similar industries, and the requirements of engines for thegeneration of electricity,have called forthmany new methods of governing, particulars of a number of which will be described in this Paper, some as types to be avoided, and others to be imitated. The Author does not intend to deal with the theory of the action of steam-engine governors, as Papersupon the subject by Professor Dwelshauvers-Dery and othershave already been printed by the Institution; but he proposes to deal with theprac- tical results which can be obtained from a great variety of types that have come under his personal observation, and the causes of 1 Minutes of Proceedings Inet. C.E., vol. civ. p. 196, and vol. cx. p. 276. P2 Downloaded by [ University of Ottawa Library System] on [13/09/16]. Copyright © ICE Publishing, all rights reserved. 2 12 RICHARDSON ON REGULATION OF STEAM-ENGlNES. [BhUtes Of theirfailure or success.l A good governorshould be reliable, simple in construction, easyto drive, and instantaneous in its action, both in increasing as well as in reducing the supply of steam. It should not reduce the power of the engine to which it is applied, but should tend to economise steam ; and, while allow- ing for greatvariations in the power of theengine, it should maintain a practically uniform speed. Mechanical Regulation.-The form of gorernor inalmost universal use until a fewyears ago was that invented by Watt,Fig. 1, Plate 3. It was connected generally through several levers and rods with the wing throttle-valve shown in Fig. 2. This governor is still largely used, and is reliable and simple. It can prevent an engine from racing when the load is removed, and may regulate it within certainlimits, but it cannot secure uniformity of speed under greatly varying loads, The speed of revolution at which the balls can be maintained when in the position 2 in the Fig., is widely different from that required when they are in the position 1, and no possible increase of speed could raise them beyond the position 3. The Porter governor, Fig. 3, is a marked improvement upon the Watt governor. A heavycentral weight A, offers a constant resistance to the lift of the balls, which are caused to revolve at a much higher speed than would be required without the central weight. This governor gives a much wider range of travel with a smaller difference of speed than the Watt gorernor,and is largely used both in connection with throttle-valves and with some forms of expansion-gear. A form of governor possessing some further advantages, which was designed by the Author about twenty years ago, is shown in Fig. 4. In this governor, the arms, instead of being suspended from a single fixed point,are suspended from twopoints and cross each other. The effective length of thearm, being that between the centre of the ball and the point A, where the arms intersect, increases as the balls rise, the increase of length being shown bythe difference between B and C. Theballs are kept close together at their lowest position, and thus as they diverge the effective length of arm increases more rapidlythan the rise of the balls. As is well known, it is quite easy to propor- tion governors of this class so thatthe sleeve will have a 1 Se0 also P. W. Willans on “The Electrical Zegulation of the Speed of Steam-Engines,”Minutes of Proccedings Inst. C.E., vol. lssxi. p. 166;and H. C. Ransom on “ Fly-Wheels and Governors,” ibid, vol. cix. p. 330. Downloaded by [ University of Ottawa Library System] on [13/09/16]. Copyright © ICE Publishing, all rights reserved. Proceedings.] RICRARDSON ON REGULATION OF STEAM-ENGINES. 213 large range of motion with very small difference in speed. While thisis a greatadvantage, it is obtained only at a sacrifice of power, and when rendered isochronous such a governor is prac- tically useless for controlling any valve or gear which requires much power to move it, as, at a fixed speed, the weighted ball will stand indifferently at any point between its lowest and highest positions. To be of the greatest use a governor must have great lifting-power, forcing-power and stability at every point of its range,and a large motion of the sleeve in proportionto the difference in speed of revolution. Theordinary pendulum gov- ernor is stable, but unless it is of great size in relation to the engine, it has but little lift,ing- and forcing-power; and in the Paper communicated to the Institution byProfessor Dwelshauvers- Dery,' he states that as a result of experiments, " The logical conclusion is, that the bestgovernor cannot, when the greatest fluctuations in the load of the engine occur, prevent the velocity from varying by at least 10 per cent." These conclusions applied to an ordinary pendulum governor, and are no doubt correct, but much better results maybe obtained by thecombination of such a governor with a spring. In such acombination anentirely new set of conditions is presented. Gravity, which is the only force causing the balls to close or fall in the Watt governor, may now be practically disre- garded, for a muchstronger force is substituted for it.Such a governor can, therefore, act equally well in any position. One of the earliest examples of this kind of governor is that designed by theAuthor in 1869, shown in Fig. 5. In additionto the spring,another feature is introduced, viz., thelengths of the armsare so proportioned thatthe balls diverge in nearly a straightline fora considerable distance. Thecentrifugal force a-venerated by revolution at a given speed at a radius of 4 inches, is manifestly much less than that generated at the same speed with a radius of 8 inches, and this large difference is counteracted by the increasing force of the spring as it is compressed. Such a governor can be made to give a travel of the sleeve of, say, 3 inches, for a change of velocity of only 4 per cent., and it has a lifting- and forcing-power of 100 lbs.; that is to say, when revolving at a speed corresponding to its lowest position, it would require an upward pressure of 100 lbs. on the sleeve to raise it to its highest position. The force requiredto move it throughthe same dis- tance when not revolving is 200 lbs. A variety of this type of * Minutes of Proceedings Inst. C.E., vol. cx. p. 277. Downloaded by [ University of Ottawa Library System] on [13/09/16]. Copyright © ICE Publishing, all rights reserved. 214 RICHARDSON ON REGULATION OF STEAM-ENGINES. [JIinutes of governor, introduced by Proell about the year 1884, is illustrated in Fig. 6. In it a heavycentral weight is substituted for bhe spring, thougll the action of the arms is similar. Instead of the increased force of a spring, a weight is lifted at an accelerated speed as the balls diverge. This governor is extremely sensitive, but has practically no lifting- or forcing-power, and needs a da,sh- pot to give it stability. Something in the nature of a dashpot is introduced in the governor and is shown in the section, Fig. 7, but as this contains air only it is almost ineffective. A perfect governor should not need a dashpot, but if one be used it should contain some incompressible substancewhich can escape only through a small aperture from one side of a piston to the other, as shown in Fig. 8. In the opinion of the Author, however, all such attempts to givestability to a governor arebut expedients to minimise an evil, which might and can be entirely eliminated. Until comparatively recently governorsfor controllingthe speed were almost universallyapplied to engines by means of thewing throttle-valve shown in Fig. 2. This valve, though simple in construction and easy to move, is difficult to fit so as to remainsteam-tight. One of the first requisites of a regulating valve is that it should be able to entirely stop the admission of steam, andthis becomes more important as the steam-pressure oecomes higher.The valve shown inFig. 9 is a considerable improvement upon the butterfly-valve. It is easier to make and easier to work, and for regulating variations in load with a good governor it acts well.