US227828A - perkins - Google Patents

Description

4 Sheet-z s-LShvet" i+1.v L. PERKINS.

. Marine and 4other Steam-Engines. 8 No. 227,82*8. Patented May 18, 1880.

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UNITED STATES PATENT OFFICE,

LOFTUS PERKINS, OF SEAFORD STREET, GRAYS INN ROAD, ENGLAND.

MARINE AND OTHER STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 227,828, dated May 18, 1880. Application filed May 3, 1879. Patented in England January 20, 1875.

To all whom it may concern:

Be it known that I, LoErUs PEnIIINs, of Seaford Street, Gray7s Inn Road, in the county of Middles'eX,Engla11d, have invented new and useful Improvements in M rine and other Steam Engines and Appefrmatus Connected Therewith, which improvements are fully set forth in the following specification, reference being had to the accompanying drawings.

This invention has more especially for its object to improve the construction of steamengines, to enable them to be worked with steam at very high pressures-say from two hundred an d fifty to one thousand pounds per square inch, and also to enable them to be, worked continuously with distilled fresh water,

provisionV being made for avoiding, as far as possible, all loss of the fresh water, so that but a comparatively small supply of fresh water is needed tomake good any loss that may take place. Y

I construct the engine with two high-pressure cylinders,two medium-pressure cylinders, i

and a low-pressurecylinder. The admission of steam to the high-pressure cylinder I arrange to be cut off at about half-stroke, and at the completion of the stroke to be expanded into the intermediate cylinder and exhausted into the opposite end of the same cylinder, which is enlarged to act as a chamber, as hereinafter described, and from there to the cut-off valve of the low-pressure cylinder.

The intermediate chamber I provide with a safety-valve loaded to about thirty pounds to the inch, and fitted with a pipe to carry oif any escaping steam to the condenser.

In working with steam at the high pressures mentioned ,no satisfactory result can be obtained with pistons packed in the ordinary manner, as the high-pressure steam affects the lubrication they require; but by con strneting the pistons in the following manner a very tight-fitting piston is obtained which will work without lubrication and with comparatively little friction.

I provide each piston with several rings or sets of rings-say siX-of hard metal, composed, by preference, of ve parts tin to sixteen parts copper. Each ring or set of rings is made to form in itselfa perfectly-packed piston, the several rings or sets of rings be- Y, ing separated from one another by Vwhat I call intermediate junk-rings. The sides of the top and bottom of the piston are also surrounded with the same metal.

Any ordinary system of breaking joint,fto gether with suitable coverplates atthe back of the joint, may be used for each packingring or set of rings to make each a complete piston in itself; and the joints between the back portions of the junk-rings, where they rest against one another, and the outer rings, where they rest against the piston, are. made perfectly tight, either by employing narrow bearing-surfaces or otherwise, so that each ring or set of rings is, as it were, inclosed in a steam-tight recess.

When the boilers are worked at'the high pressures before mentionedV ordinary glass water-gages cannot safely be used,I as their glasses crack at once if a cold current of air comes against them. It is therefore necessary to Vemploy plates of mica instead of glass. Mica water-gages, however, as previously constructed would not stand, as the red lead or other soft packing interposed between the plates of mica and the metallic portions of the gage became quickly destroyed and the gages leaked. To obviate this, and to secure a tight joint between the two plates of mica and the two opposite faces of the body of the gage against which they are held, I form on each face, around the opening formed through it, a narrow raised edge, against which the mica is firmly pressed'by a metal plate applied to its front face. All the bolts used for drawing these plates against the mica are to be tinned, or may be made of copper, to prevent them from rusting and acting injuriously upon the mica.

To avoid loss from leakage, and prevent all access of salt-water to the water for working the engine, all pipe and other joints are, as far as possible, metallic joints, a narrow ring, of copper or such like soft metal, being compressed between the two surfaces between which a joint is to be made.

To avoid loss when steam is blowing off from the safety-valves the steam is conducted from these valves `to the condenser, as has before been proposed.

To avoid loss of steam when the engines IOO are at any time stopping, the necessity of blowing oft' steam except through the safetyvalves leading to the condenser, is avoided by providing a small auxiliary engine to work independent circulating and feed pumps, and, it may be, also air-pumps, for the purpose of maintaining a vacuum in the condenser and returning the condensed water to the boilers, the exhaust from this auxiliary engine heilig' also led into the condenser so that no loss of steam shall take place when working it. rIhe hot-well also is made large enough to contain as much water as can safely be taken from Athe boilers.

The main and auxiliary air-pumps and circulating-pumps are so arranged that whenever one or other of them is not at work Vit shall be kept charged with water by the pump that is at work, so that the pumps shall always be maintained in a state to work ehiciently whenever they maybe put into action.

To prevent access of salt-water to the water used for working the engine through the nonreturn valve provided for the escape ot steam or vapor from the hot-well, should the condenser at any time not be in thorough working order, and to prevent scalding the crew, this Valve is fitted in a pipe leading upward from the hot-well to the funnel.

For distilling and for heating salt-water, steam-coils are used, connected at onel end with the 'steam-space of the boilers and at the other to the hot-well, so that no loss ofthe water used for working the engine shall be occasioned, and also so that when the distilling apparatus or salt-water steam-generator is not required to be in use the admission of stealn to the steam-coils may be shut oft' by valves, so that noheat shall then be taken off through them from the boiler.

The steam produced in the salt-water steamgenerator is employed for all the various purposes where steam is required to run to wasteas, for example, for heating, cooking, blowing the whistle, workin g donkey-engines, for hoisting, and such like.

To maintain a uniform feed to each of the boilers either two separate feed-pumps are used for each boiler or an accumulator is to be interposed between the boilers and pumps.

In the drawings I have not shown any complete steam-engine, as the form of the engine may vary considerably. The drawings show the lnanner in which I form the high and medium pressure cylinders of the engine and the pistons working in them, also the valves for controlling the passage of steam to and from the cylinders.

Figure l isavertical section of one pair ofthe high and medium cylinders of the main engine and of the pistons working in these cylinders. Fig. 2 shows a section of the valve for controlling the admission of steam to the highpressure cylinder and the 4passage of steam from this cylinder into the medium-pressure cylinder. Fig. 3 shows the valves for controlling the admission of steam to and escape from the medium pressure cylinder. The smaller valve, which is also shown at Fig. 2, is the valve for admitting steam to the medium-pressure cylinder, and the largerA valve for delivering the steam from this cylinder into the chamber above the piston of the medium-pressure cylinder. The valve I employ for delivering steam from this chamber to the opposite ends of the low-pressure cylinder is shown at Fig. 4. A similar valve is employed for controlling the exhaust from the ends of this cylinder.

The manner in which I obtain a tight packing for the pistons of the steam-cylinders and also for the piston of the valves is shown clearly at Fig. 1.

A is one ofthe high, and B one of the medium, pressure cylinders of the engine. The low-pressure cylinder is not shown. The manner in which the high and medium pressure cylinders are formed is shown elearl y from the drawings.

Steam is rst admitted to the top of thehighpressure cylinder' for about half the stroke and is expanded for the remainder. Afterward it is exhausted into thelowerend of the cylinder B. Here again it is allowed to expand, and

at the end of the stroke exhausted into the upper part of this cylinder, which is carried up so as to form an annular space around part of the highpressure cylinder, as shown. On the exterior of the medium-pressure cylinder there is also an enlargement yof this space leading to the valve by which steam is allowed to pass to the low-pressure cylinder. To this space is also attached a safety-valve, as before explained, all steampassing from which is led to the condenser. The manner in which the pistons are constructed is also shown in this figure.

a a are junk-rings; I) b, piston-rings, made to break joint in any usual manner, and with cover-plates at the back of thej'oints to make each ring into a complete piston. These coverplates may either be rings passing ventirely around the back of the piston-rings, or may only be applied at the joint, as desired.

The drawings show six piston-rings to each piston; but this may be varied, and two, three, or more rings may be similar] y employed. As before explained, tight joints are made between IOO IIO

the several j unk-rin gs where they m eet together at the back of the piston-rings, and also between the outer rings and the piston. The piston-rings are of hard metal, as before stated, and the sides ofthe top and bottom of the piston are surrounded with the same metal, as shown.

I would remark that I am aware that it has before been proposed to construct pistons with two, three, or more split piston-rings, known as Ramsbottom rings,77 sprung into separate grooves formed around the piston 5 but my con struction of piston differs from this arrangement in that each ring forms a. completelyjunk-rings may also be employed, as before ure cylinder A.

stated, for packing the glandsthrough which the piston-rods pass. y

I will now proceed to describe more fully the constructionof thepiston-valves shown at Fig. 2, in which the same arrangement of packing is-adopted; but to the construction of these valves, or as regards their packing,

VI make no claim herein, except to the arrangementor combination with other features.

It will be seen that each valve-piston is furnished with piston-rings in a similar manner to that above described with regard to the 'pistons which work on the steam-cylinders.

Each valve-piston Works in a cylindrical lining, c, closed at one end and open at the other for 'the passage of steam. Zd are the ports nformed through the side of the lining.

Steam is admitted from the boiler to the space between the lining and the cylindrical casin g of the smaller valve, and when the ports in the lining are uncovered by the piston steam passes to the space surrounding the lining of the larger valve and into the high-press- The admission of steam to this cylinder is cut off at about half-stroke, and the steam is expanded in the cylinder for the remainder. At the end of the stroke the larger piston-valve is opened, and the steam allowed to pass through it from the highpressure -to the mediiun-pressure cylinder.

The piston of each valve has passages formed through it from end to end, so that the pressure upon the two ends of the piston is approximately balanced.

It will be seen that in each of these valves the pressure of the steam is upon the exterior of the rings of the piston-valves, so that as the valves are closing the rings are not pressed outward by the steam.

By thus arranging piston-valves that are to be subjected to high pressure the wear upon the valves is much reduced.

In order that the packing in the gland through which the piston-rod of the high-pressure piston-valve passes may be renewed without allowing any escape of steam and without stoppingthe working of the engine, I form a valve-face around the piston-rod at the end of the piston, which, if the piston is moved slightly beyond the end of its stroke, comes against a valve-face at the end of the gland and forms a steam-tight joint. When the piston-rod has been disconnected from the valvegear and has thus been moved the packing may be removed and fresh packing inserted. 4During the timethe valve is thus put out of action steam may be allowed to pass continuously from the boiler to the high-pressure cylinder through a icy-pass valve.

The stop-valves and other valves may be similarly constructed to allow of the packing smaller valve, which is also shown in Fig. 2,

is the valve for admitting steam to themedium-pressure cylinder, as before explained,

and the larger valve is for delivering the steam' from this cylinder into the intermediate chamber which surrounds the high-pressure cylinder, as shown at Fig. l. The valve I employ for delivering steam from this chamber to the opposite ends of the low-pressure cylinder is shown at Fig. 4. A similar valve is employed for controlling the exhaust from the ends of this cylinder.

For the inlet-valve steam is admitted from the intermediate chamber to the central port, e, and, as the piston is moved to and fro, is allowed to escape alternately by the outer ports, fand g, to the opposite ends of the lowpressure cylinder.

For the outlet-valve the action is reversed, and steam passes from the ends of the cylinder to the outer ports, and is delivered from the centralport to the condenser.

It will be seen that in these valves also the pistons work within linings, which have the ports formed in them in a similar manner to that shown in Figs. 2 and 3, and that these linings can readily be, inserted into the cylindrical valve-casing from its two ends.

An y suitable arrangement of valvegear may IOO be employed for working the several valves,

so that I have not thought it necessary to show any inthe drawings. Other valves than those shown might also be used for controlling the passage of steam to and from the cylinders.

At Figs. 5, 6, and 7 I have shown a mica water-gage, which may be used with safety at the high pressures before mentioned.

The novelty in the construction of this gage, to which, per se, no claim is herein made, consists in forming theV oppositefaces of the body of the gage with narrow raised edges o around the opening, as shown at Fig. 5. The sheets of mica are pressed against these edges by slotted cover-plates p, one of which is shown at Fig. 7. By this means the sheets of mica aige'securely held and a tight joint obtained without the use of any material which might be iuj urious to the mica.

Fig. 6 shows an edge view of the gage.

Having thus described the nature of my ind IIO vtween the larger and smaller cylinders, substantially as and for the purpose hereinbefore Set forth.

2. The combination of the two larger or me- 5 dimm-pressure cylinders, the two smaller or high-pressure cylinders, arranged, respective ly, at the ends of the high-pressure cylinders vand projecting into them, thus forming the annular spaces into which steam is exhausted 1o from the medium-pressure cylinders, the two piston-rods, and the pistons arranged in pairs for a high-pressure and a medium-pressure cylinder, each pair carried upon its respective Arod common to both cylinders, substantially 15 as and for the purpose hereinbefore set forth.

.LOFTUS PERKINS.

Witnesses:

CEAS. BERKLEY HARRIS, JOHN DEAN, Both ofl Graceclmwch Street, London, E. C.

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