US1467489A - Compressor - Google Patents

Description

Sept. 11, 1923. 1,467,489

B. v. .NORDBERG COMPRES S OR Filed Aug. l2, 1918 4y Sheets-Sheet'l 5 Ew-Mmmm@ E. V. NORDBERG COMPRESSOR Sepp. 11, 1923. n,467,489

Filed Aug. 12, 1918 4 Sheets-Sheet 2 Si &\\\\\\\ Sept.,11,.1923. '1,467,489

B. V. NORDBERG COMPRESSOR Filed Aug. 12 1918 4 Sheets-Sheet 4 1 Innern/{b11- BMWNMMu/ Patented Sept. 11, 1923.

UNITED STATES BRUNO v. NORDBERG, F MILWAUKEE, WISCQNSI.

COMPRESSOR.

Application led August 12, 1918. Serial No. 249,405.

To all whom i may concern.'

Be it known that I, BRUNO V. NORDBERG, a citizen of the United States, residing at- Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Compressors, of which the following is a specification, reference being had to the accompanying drawing, forming a part thereof.

This invention relates more particularly to .high duty multi-stage compressors for compressing air or gases, especially inflaminable or poisonous gases, to high pressures.

lts main objects are to provide reliable and efficient means for compressing air or gases to high pressure; to minimize leakage through pipe connections, joints, and stuing boxes and prevent escape of inflammable or poisonous gases from a compressor into the atmosphere; to make the pistons `and stuifing boxes leasily accessible without disturbing the suction and discharge pipe connec' tions or the mounting of the cylinders; to

provide for easily disconnecting such a compresser from the engine or motor by .which it is normally actuated and for operating it by hand in an emergency as in the case of a small compressor used in connection with a small internal combustion marine engine for starting and maneuvering the engine; and generally to improve the construction and operation of compressors of this class.

It consists `in the construction, arrangement and combination of parts as hereinafter particularly described and pointed out in the claims. l

In the accompanying drawing like characters designate the same parts in the several figures.

Figure lis a vertical axial section of a two-cylinder four-stage compressor embodying the invention; lFig. 2 is an axial section on the line 22, Fig. 1; Fig. 3 is an enlarged axial section of one of the suction valves; Fig. 4 is a similar section of one of the discharge valves; Fig. 5 is an enlarged section of the two cylinders in a plane at right angles to that of Fig. 1, showing the suction and discharge valves, the connections of the two cylinders with intercoolers, and the leak connections; and Fig. 6 is a sectional diagram of a modification showing a four-stage compressor'having a single cylinder and a single piston.

The essential principles of the invention may be embodied in a multi-stage compressor of any desired number of stages, with a single stepped cylinder and. a single differential or stepped piston or with two or more such cylinders and pistons.

Referring to Figs. 1 to 5 inclusive, showing a four-stage compressor specially designed for compressing to high pressures,'say, 100

atmospheres or more, inammable 0r poisonous gases, there are two stepped water jacketed cylinders, 1 and 2, each formed with two intercommunicating coaxial bores oi larger and smaller diameters, and each of these cylinders is provided with a single `dif- Y with the bores of the Cylinders in which they.

are fitted and are lprovided with suitable packing rings.

The spaces 5 and 6 in the larger bore of the cylinder 1 on opposite sides of the larger head or step 7 of the piston 3, form the first or low pressure stage; the space 8 in the distant end of the smaller bore of the cylinder 1 forms the second stage on one side only of the smaller head or step 9 of the piston4 3; the space 10 in the larger bore of the cylinder 2 below the larger head or step llof the piston 4, forms the third stage, and the space 12 in the smaller bore of the cylinder 2 be- .low the smaller head or step 13 of the piston 4 forms the fourth stage.

As shown in Fig. 5, the low pressure spaces 5 and 6 of the first stage are connected through suction valves 16 at opposite ends of the larger bore of cylinder 1 and by a pipe 17 with a holder or reservoir 18, from which the gas to be compressed is drawn. The

spaces 5 and 6 are also connected through.

discharge valves 20 at opposite endsof the larger bore of the cylinder 1, and by a pipe 21 with an intercooler 22. which is connected by a pipe 23 and througha suction valve 24 charge valve 32 and by a pipe 33 with a third intercooler 34, which is connected by a pipe 35 and through a suction valve 36 with the space 12 of the fourth or high pressure stage in the smaller bore of cylinder 2. The space 12 is connected through a discharge valve 38 and by a pipe 39 with the compressed air or gas receiver (not shown).

The idle space 42 in the upper end of the larger bore of cylinder 2 is connected by a pipe 43 with a part of the compressor 1n which a lower pressure is maintained than is produced in the working space 10 in the other or lower end of said bore, for example, as shown, with the irst intercooler 22.

The cylinders 1 and 2 are provided at their larger ends with removable, heads 45 and 46, and these heads are provided with stuiiing boxes 47 and 48 for the piston rods 49 and 50 of the respective pistons 3 and 4.

A single stuing box is thus made to suffice for two stages of the compressor, the stufing box 47 for the first or low pressure and second stages represented by the spaces 5, 6 and 8, and the stuiling box 48 for the third and fourth or high pressure stages represented by the spaces 10 and '12.

Y To facilitate removing and replacing the pistons and to locate the stufling boxes in the most accessible positions on the compressor, where they may be easily observed and taken care of, the cylinders are preferably mounted vertically as shown, with their larger ends and removable heads uppermost.

As shown in Figs. 1 and 2, the piston rods 49 and 50 are fastened at their upper ends in cross heads 54, which are connected by parallel rods 55 extending downwardly and guided on opposite sides of the cylinders 1 and 2 with cross heads 56.

The cross heads 56 have adjustable .pivot or journal bearings at their ends in slides 58 guided in vertical parallel ways 59 in the compressor frame.

The cross heads 56 are connected by rods 62 with the crank shaft 63 of the engine or motor.

The connecting rods 62 are preferably shouldered and threaded at their upper ends and provided with nuts 64, so that they can be easily and quickly disconnected from the cross heads 56. Such a detachable connection between the compressor and engine or motor is particularly convenient and advantageous when va single-cylinder, twostage compressor 0f small size is used in connection with a small marine or internal combustion engine for-maintaining a supply of compressed air to start or manoeuver the engine.

In case the supply of compressed air is exhausted or reduced to a pressure at which it will not start the engine, it is sometimes necessary to disconnect the compressor from the engine and operate it by hand. For this purpose, by removingthe nut 64, thesrod 62 connecting the cross head 56 with the crank shaft 63 of the engine, is detached and the compressor piston can be operated by f a hand lever connected with the cross head ing or pocket in the cylinder wall, a separate and reversible seat section 67 formed with a circular series of ports 68, an annular valve disk or plate 69, fitted to one end of the seat section 67, and normally covering the ports 68, a spring seat or bearing 70, detachably fastened by a central bot 71 to the seat section 67, a spiral spring 72 interposed between the valve disk or plate 69 and the seat or bearing 70, and a cover 73 fitting in the outer end of the opening or pocket in the ycylinder over the valve cage. The discharge valve shown in Fig. 4 is of like or similar construction, except that the cage 66 is somewhat longer than Ithe cage 66 of the suction valve. The valve seat 67 with the valve disk or plate 69, the spring seat or bearing 70 and the spring 72, are reversed in the discharge valve, so that the valve will open outwardly from the cylinder instead of inwardly like the suction valve, shownin Fig. 3.

To prevent leakage from the compressor cylinders into the outer atmosphere when inflammable or poisonous gases are compressed, hoods or bonnets 7 6 and 77 are bolted or detachably fastened to the removable heads 45 and 46 and form or enclose chambers around the piston rods 49 and 50 over the stuing boxes 47 and 48. These chambers are connected by piping 78 with the gas holder or reservoir 18, or with the suction inlet of the compressor, in which atmospheric or a very low pressure is maintained. The hoods or bonnets 76 and 77 are provided with stuing boxes 80 and 81, which prevent any leakage therefrom around the piston rods into the outside atmosphere, if for any cause the pressure inthe chambers formed or enclosed by the hoods or bonnets from leakage through the. main stuiiing- l boxes 47 and 48 is absolutely prevented.

Between the removable heads 45 and 4 6 and the larger bores of the cylinders 1 and 2 into which they are fitted, annular joints 84 are formed or provided. which are designed to withstand the highest pressure within the spacesv 5 and 42. These joints may be formed by accurately ground opposing faces o f the heads and cylinder walls,

but for greatersecurity are preferably made by inserting packing rings of other sott or compressible metal between opposing shoulders, one of which may be beveled or inclined, formed on the heads and in the cylinders, these packing rings being squeezed by tightening the bolts, fastening the cylinder heads to the cylinders, to conorm with and fill or nearly fill the spaces between the opposing shoulders.

Annular chambers .86 are formed outside of the joints 84 between the removable heads and 46, and the cylinder walls, and these chambers are connected by the piping 78 with the gas holderor reservoir 18 or with the main inlet of the compressor. The chamber formed or enclosed by the hood or bonnet 77 over the stutiing box 48 communicates through an Lopening 88 with the annular chamber 86 formed in the head 46, so that a single connection with the piping 78 suiiices for both of said chambers, as shown in Fig. 5, While separate connections with said piping are made for the chamber formed by the hood or bonnet 76 and the annular chamber 86 in the head 45. v

Outside of the annular chambers 86, annular joints 90 are formed between the heads 45 and 46 and opposing walls of the Vcylinders 1 and 2. These joints preferabiy consist of rubber or other soft packing com- Dressed between opposing shoulders or faces of the heads and cylinders, and absolutely prevent any leakage from the chambers 86 into the outside atmosphere, if for any cause the pressure in said chambers should slightly exceed that of the atmosphere or that maintained in the gas holder or reservoir 18.

As shown in Figs. 3, 4 and 5, like or similar joints 84 and 90 with intervening annular chambers 86 are formed between the valve covers 73, valve cages 66 and 66 and the opposing walls of the cylinder pockets or openings in which they are fitted, and these chambers are also connected by the piping 78 with the as holder or reservoir 18 or with the main inlet of the compressor.

For convenience of construction the cylinders 1 and2 are preferably provided at their smaller ends, as shown, with separate heads 92 and 93, which are permanently bolted to the cylinders and between which and the cylinders, tight joints are formed. These joints like the joints 84 between the removable heads 45 and 46, at the upper larger ends of the cylinders, may consist of copper or other soft metal packin rings compressed between opposing shou ders of the heads and cylinders, and are easily made and kept tight since the heads 92 and 93 are inrequently or never removed from the cylm ers.

A compressor of any desired number of stages, two or more, may be built upon the same principle and according to the invencopper or tiongas hereinbefore described, with a single cylinder 1 and a single piston 3', as diay.

grammatically shown in Fig. 6.

In the operation of the compressor, whether it comprises two or more stages, the air or gas compressed in the spaces 5 and 6 ot the first or low pressure stage,l is discharged therefrom through the vvalves 20 into the first intercooler 22, in which it is cooled approximately to the initial temperature of the air or gas and from which it is drawn at that temperature through the suction valve 24 into the space'8 of the second stage, or in the case of a two-stage compres sor, the high pressure stage, from which it is discharged through the valve 26 and pipe temperature, and from which it is drawn through the pipe 29 and suction valve 30 into the space 10 in the larger bore of the cylinder 2, constituting the third stage of compression, F rom the space l() of the third stage the more highly compressed gas or air is discharged through the valve 32 and pipe 33` into the third intercooler 34, in which it is again cooled to approximately its initial temperature and from which it is drawn through the pipe A35 and valve 36 into the space 12 of the last or high pressure stage.

From .the fourth or high pressure stage, the highl compressed air or gas is discharged t rough the` valve 38 and pipe 39 into the receiver.

It will be'observed that the piston head or* step 7 of the low pressure stage is double acting, while each of the other piston heads or Isteps 9, l1 and 12, is single acting, and that there is but one stuffing box for each cylinder comprising two stages, and each .stuifing box is subjected only t'o the pressure of the first or low pressure stage. Any yleakage which may occur past the acking' rings of the piston head or step 9 rom the space 8 of the second stage into the s ace 6 of the first or low pressure stage, wou d slightly increase the pressure in the space 6 and correspondingly increase the power required for' compression of theair or gas, but would not reduce the capacity of the compressor.-

The space42 in the largerbore of the cylinder 2, which has no valves and is connected with the intercooler 22 between the first and second stages, does not contribute to the compression of the air'or gas. The low pressure of. the first stage is maintained in this space in order to'minimize any leakage between the thirdand second stages by reducing the pressure difference between the spaces 10 and'42.

In a comp-ressor of any desired number of stages, two or more, the several stages may all be arranged in axial alignment with one another, the steps of the cylinder for the several stages diminishing in diameter from one end of the cylinder to the other, so that there will be no idle cylinder spaces, thus making the machine more compact and tending to avoid leakage between adjoining stages, as shown for exam le, in case of a two stage compressor, by Fig. 2, and in case of a four stage compressor by Fig. 6. The cylinder barrel for the several stages is cast in one piece or in sections connected with each other by permanent joints, thereby avoiding 'loose or insecure joints which are liable to leak, thus allowing gas to escape into the surrounding atmosphere and impairing the eicienc of the compressor.

By making the piston of the first or low pressure stage double acting, its diameter and hence the greatest diameter of the cylinder are materially reduced, thus further tending to avoid leakage between the first and second stages and effecting a. saving in ythe cost of the compressor.

The space 42 might be connected with the main inlet of the com ressor, but in that case the leakage from tliie third stage, whatever it might be, would cause a loss of capacity, which is not the case with the arrangement shown and described, since any leakage between the s aces 10 and 42 would not reduce the capacity of the compressor, but would slightly increase the power required to operate 1t.-

Any leakage of gas past the joints 84 between the removable cylinder heads 45 and 46 and cylinders and between the valve covers 73 and the walls of the valve openings in the cylinders, is trapped 'in the annular chambers 86, and drawn therefrom through the piping 78 into the gas holder 18 or main inlet of the compressor.

Any gas leakage through the main stuffingk boxes 47 and 48 from the low pressure spaces 5 and 42 into the chambers formed by the hoods or bonnets 76 and 77, is likewis/e withdrawn therefrom through the piping 78 into the gas holder 18 or main inlet of the compressor. t

In this way, inflammable or poisonous gases are absolutely-prevented from escapvving from the compressor into the surround;`

ing atmosphere.

The principal and 'essential features of the invention (may, as hereinbefore stated, be embodied in a compressor of any desired number of stages with a single stepped cylinder l', having intercommunicatm coaxial bores of different diameters, an a single differential or stepped piston 3', as shown in Fi 6 without loose or insecure joints and id e cylinder spaces between the stages.

compression, the larger bore of the low pressure stage being provided at each end and each smaller bore of a higher pressure stage being provided at its distant end only with suction and discharge valves, a removable head fastened to the larger end of the cylinder and provided with a stuffing box, and a stepped piston fitting the several bores of the cylinder and provided at its lar er end with a rod passing through the stuilmg box in the removable cylinder head, thei larger step of the piston being double acting and cach small-er step single acting, and the piston being removable through the larger end of' the cylinder without disturbing the mounting and suction and discharge pipe connections of the cylmder.

2. In a compressor the comblnation of a cylinder permanently yclosed at its smaller .tuting' separate stages of compression, thel larger bore of the low pressure stage being provided at each end andv each smaller bore of ay higher pressure stage being providedI at its distant end only with suction and discharge valves, a removable head fastened to the larger end of the cylinder and provided with a stuiiing box, anda stepped piston fitting the several bores of the stepped -cylinder and provided at its larger end with a rod passing through the stufling box inthe removable cylinder head, the piston removable through the larger end ofthe cylinder without disturbing the mounting and suction and discharge pipe connections of the cylinder, and all spaces within the cylinder being active compression spaces.

3. In a compressor the combination of two cylinders each having intercommunieating bores of larger and smaller diameters corresponding with lower and higher stages ofcompression, each end of the. first stage cylinder bore anda single end of each succeeding intermediate stage and of the last cylinderand provided at its larger end with tained than is a rod passing through the stuffing box in the removable head, the discharge of each intermediate stage being connected with the inlet of the next higher stage, and the idle end of the larger bore of the smaller cylinder bein connected with a part 'of the compressor 1n which a lower pressure 1s mainsaid bore.

4. In a compressor the combination of a cylinder having a removable head provided with a stuing box, a piston fitting the cylinder and provided with a rod passing through the stuiling box in the removable head, and a bonnet forming with said head a chamber aroundthe piston rod over and enclosin the stuiiing lbox in the removable head, said chamber being connected with the inlet to the compressor to collect gas which may leak through the stuiing box to be conducted back to the inlet of the compressor.

5. In a'compressor the combination of a cylinder, a piston fitting said cylinder, a tted to the cylinder, two separated annu ar joints betwen the cylinder and itsremovable head, and 4an annular chamber betwen the jointsand opposing walls of the cylinder and removable :head

connected with the `inlet to the compressor.

6. Inacompressor the combination with a cylinder provided'with a valve chamber, vof a removable cover fitted to said chamber,

-spaced fluid-tight annular joints between the cover and wall of the valve chamber, and an annular chamber between said joints conj nected with the inlet to the compressor.

7. In a com ressor the combination with Y a cylinder having one open end, of a remov-` able head fitted to the .open end of the cylinder, .spaced annular joints between the head and cylinder wall, and an annular chamber located between said joints vand connected with the inlet to the compressor.

8. In a compressor the combination with produced in the other end ofV -able covers fitted to the valve openings,

spaced' annular joints betwen the head and covers and the cylinder, and annular chambersl located betweensaid joints and connected with the inlet to the com ressor.

9. -In a compressor the combmation of a cylinder provided around an openin into its bore with spaced annular shoul ers, a closure fitting into the opening and formed with spaced annular shoulders opposing the shoulders around the cylinder opening, a soft metal packing interposed between the inner shoulders, elastic packing vinterposed between the outer shoulders,.and an annu'- lar chamber located between the joints formed by saidshoulders and packing and connected with the inlet to the compressor.

10. In a compressor the combination of a cylinder having adjoining coaxial bores each provided for a single stage of compression,

the bore of the low pressure stage bein pro` vided at each end with' suction an vdiacharge valves, and the adjoining smaller bore being provided at its distant end only withsuction and discharge ,valve's, all 'spaces within the cylinder being active com ression spaces, a head detachably fastene to the larger end of the cylinder and provided with a stuilingv box, and a stepped piston fitting the bores of the cylinder and provided at its larger end with a rod passing through the .i

BRUNO V. NORDBERG. I

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