ON STEAM NAVIGATION AT HULL. 



123 



main nearly the same ; this is also the case with sea-going and river boats be- 

 longing to other places, but trading to Hull. 



Silver's Patent Marine and Stationary Engine Governors. Constructed by- 

 John Hamilton, Engineer, Glasgow. 



The Engraving represents the Momentum Wheel Governor or " Nautical Regulator," as 

 it is usually placed in the Engine-room of a Steam-Ship. It consists of a momentum wheel, 

 A, fixed on the boss of a pinion, B, which works loosely on the spindle, C, and gears into the 

 two-toothed sectors, D D. These two sectors being supported on a crosshead, E, made fast 

 to and carried with the spindle, C, work in opposite directions on the pinion, B ; and, as they 

 are linked by the rods, F F, to the sliding collar, G, which receives and works the forked 

 lever, H, communicate motion to the throttle valve. M M are vanes, and N is a spiral spring, 

 both of which are adjustable. 



The action of the above Instrument is as follows :— When the spindle of the Governor or 

 " Nautical Regulator " is turned by the engine to which it is attached, the two-toothed sec- 

 tors, which are carried on the fixed crosshead, being geared into the pinion on the momentum 

 wheel, have the tendency to turn round on this pinion ; but as they are linked to the sliding 

 collar, they necessarily pull inwards this collar, and so compress the spiral spring; and this 

 spring, reacting on the collar, and consequently on the toothed sectors, serves to turn round 

 the momentum wheel, while the vanes on the momentum wheel balance the action of this 

 spring by the resistance the atmosphere offers to their progress through it. As the leverage 

 action of the toothed sectors upon the momentum wheel pinion increases, as the spring be- 

 comes distended, and vice versa, it will be seen that the reaction of the spring in propelling 

 the momentum wheel will at all times be uniform, and as much only is required as will carry 

 round the momentum wheel with its vanes at its proper speed, and overcome the friction of 

 working the throttle valve, and throttle valve connexions. When the momentum wheel is 

 in motion, it will rotate with the engine to which it is attached, at a velocity proportioned 

 to that at which it is fixed by the connecting gear ; and while the engine from the usual 

 causes may attempt to vary this velocity, it cannot affect the momentum wheel, but leaves 

 it free to act upon the sliding collar, and consequently upon the throttle valve— at one time 

 closing the throttle valve by its action in resisting any increase of velocity, and at another 

 time opening the throttle valve by its action in resisting any decrease of velocity on the part 

 of the engine. It will now be evident that the power of such a Governor or Regulator must 

 be very great indeed, having for its agent a momentum wheel which may be increased to any 

 dimensions ; and from the powerful resisting tendency of such wheel, it necessarily follows 

 that its sensitiveness of action must also be very great, and in exact proportion to the 

 tendency of the engine to vary its speed ; and the engine itself being the direct prime mover 

 of the throttle valve, it also follows that the inert power of the momentum wheel increases 

 its resistance exactly in proportion to the rapidity with which the engine varies its speed. 

 Hence a momentum wheel of 2 feet 8 inches diameter, and 2 inches periphery, running at a 

 speed of 180 revolutions per minute, is found to be sufficient to work with promptness and 

 ease the largest throttle valve, and to equal the power of several men. Unlike the ordinary 

 forms of Governors, it is entirely unaffected by changes of position, and therefore perfectly 

 adapted for Marine and Portable, as well as Stationary Stcam-Engincs. 



