US1240531A - Regulating mechanism for centrifugal compressors. - Google Patents

Description

O. BANNER.

HEGULATING MECHANfs'M Roh cENRIFUGAL GOMPRESSORS. APPLICATION FILED SUNESO. 19M.

, anism for centrifu ers, and more particularly to mechanism for' fluid below the so-called 4 25,

erro BANNER, or EAsT'oN, PENNsYLvaNrA,

PAN'Y, on JERSEY CITYyNEW JERSEY, A CORPORATION 0F ASSIGNOR TO INGERSOLL-RAND COM- JERSEY.

Tov all wlwm 'it may concern,.-

Be 1t. known that I, Or'ro BANNER, a subject of the German Emperor, residingiat Easton, in the county of Northampton and State of Pennsylvania,have invented a certain new and useful Improvement in'Regu.-

lating Mechanism for Centrifugal Compressors, Case B, of which the following isa peciication. i

's invention relates to regulating vmechal compressors and blowregulating the operation of such compressors below their norma-l capacit y en the airor other uid delivered by a centrifugal compressor or pum falls below a certain amount, which is etermined by the size and design of the compressor or pump, the fluid in the compressor begins to pulsate back and forth through the impellers giving the effect known as pumping.

It is often necessary, however, to operate such a compressor to deliver an amount of pumping limit. To do this various methods have been devised, the most. common being to 'allow enough fluid to pass through the compressor to prevent pumping, but to blow off whatever eX- cess'there is over'the demand to the atmossis , and passed out i uated a spring plate check phere from the This, of course, of energy. f The object of this invention is to provide a means whereby a compressor can be safely operatedbelow the pumping limit without any waste of' the pumped fluid.

`lfVith this object in View, a regulator has been devised, practical embodiments of which are shown in the accompanying drawings, in which,

Figure 1 shows a partially diagrammatic side elevation of a compresso1system embodying the invention, the important features vbeing in section, and

Fig. 2 shows a detail of a modified form. In the drawings is shown a centrifugal compressor l, of ordinary iconstruction, driven by a steam turbine 2, alsofof ordinary constructimi. Air or other fluid is takenI into the compressor through an inlet pipe 3 through the discharge line 4. Situated in the discharge line 4 near the compressor is a valve chest 5 in which is sitvalve 6 which is preferably of very light construction and compressor discharge line. involves considerable waste f- ,Y Specification of Letters Patent.

Application led June 30, 1814. Serial No.

Patentes sept. is, rear. seais?. l

allows free iow or the compressed luid to the Work but prevents any return flow to the compressor.l v

, When the compressor is operated below its pumping limit the pressure in the discharge line fiuctuates between the the compressor is designed to nornially'produce and a very much lower pressure, the pressure alternately rising and falling as the machine pumps. The addition ot' the check valve 6 in the discharge line prevents any fall in pressure on its farther side so that when the compressor operates normally a quantity of air or fluid at the requiredpressure passes through the valve and can not return, while when the compressor is pumping, no air passes by the valve except at the height of. the pressure of each of the pumpingpulsations. If the air from the compressor is to be used directly it is necessary to provide'an auxiliary receiver 7, to

prevent undue varia-tion in the pressure of the Huid delivered. 1 As the regulation of the driving motor of a compressor isusually effected by the pressure of the discharged fluid, the effect of the pumping on the regulating mechanism must also be' considered. l

In the drawing is shown an ordinary mechanism for regulating the steam admission to the turbine 2 in accordance with the speed and the discharge pressure of the compresser, this mechanism comprising a throttle valve 8, controlling the admission of steam to the turbine 2 through the pipe 9. The valve 8 is provided with a stem l() which is attached to the center. of a lever 11 operatively conneetedwith a ball governor 12 driven by connections. -(not shown), from the main shaft of the turbine. The other end of the lever 11 is attached to thepiston rod 13 of a piston 14- sliding in a cylinder 15. The piston 14 is moved through a relay mechanism which consists of apilot valve 16 sliding in a chest 17 to which oil is admitted by a pipe 18 from a source of oil under pressure, (not shown), and from which oil is exhausted by pipes 19. Oil is admitted and exhausted from the upper and lower sides oi' the piston 14 by pipes 20 and 2l, the movement of valve 16 upward causing admission to the upper side of piston 14, moving it downwardly and the movement of valve 16 downwardly admitting fluid to the lower side of piston 14 moving it upwardlv.

pressure whichl gli' iat

Mun-" i admission of steam to the'turbine.

vThis pilot valve is m'oved by a piston 22 sliding in a cylinder 23, the piston 22, valven 16, and piston 14 being connected to each. other by a follow up lever 24,4 vthis whole relay mechanism being of well known construction. The' piston 22 has an adjustable spring 22a tending to moveA it upwardly, while the upper end of the 'cylinder 23 is connected by means of a pipe 25 to the discharge line 4 of the compressor between the compressor and the check valve 6. As the pressure in the pipe 25 varies the piston 14 and hence the valve 8 are moved to vary the were able to pass freely through the `pipe 25 in both directions when the compressor was pumping the valve 8 would be moved l up and down with the pulsations of the compresser, alternately closing oil the steam and allowing it to enter the turbine, the alternations being of considerable rapidity.

It is obvious that the sharp blows result- "ing from the impact of the steam on -the blades of the turbine would result in wear4 and breakage. To prevent this pulsation of the valve 8 a valve chest 26 is'provided in the pipe 25 in which is situated a check valve 27, which allows free movement of the fluid through the pipe 25 to; the cylinder 23 but which cuts oil' the flow in' the other direction. A limited flow in the other direction is allowed, however, through a leak port 28 which can be adjusted byv means of a screw 29.

l/Vhen the compressor is operating under normal conditions above the pumping limit, the pressure changes in the discharge line fi and hence in the pipe 25 are small, the pressure rising slightly when the demand falls nii causing the piston 22 to move downwardly, the piston 14 upwardly,'and the valve 8 to shut ofi the admission of the steam to the turbine to a slight extent. Any fall in pressureis also gradual and the fluid lcan easily escape through the port 28. y

TvVhen the compressor is pumping, however, it is necessary for there to be a free fiow of thc fluid through the pipe 25 in a direction to close the valve 8, but the ow in the other direction must be restricted so that when the pressure in the discharge line i falls, the 'fall cannot be communicated suddenly to the cylinder 23 and hence to the valve 8. This fall must be gradual, and if thc capacity oit the pipe 25 between the cyl lniler 23 and the valve chest 26 is not suiiicicnt an auxiliary receiver 30 must be added.

bei" 848,146 filed June 30th, 1914, have .shown and `described a regulating mecha msm'accomplishing the same purpose as the present, in which the pipe corresponding to pipe 25 is led from the discharge line-bea yond the check valve, the mechanism for pre-r venting the rapid'communication of the fall in pressure in theA discharge line to the pres sure regulating mechanism not being neces sary in such a case. Y

With. this invention a steam driven centrifugal compressor can be 4successfully oper, ated below its pumping limit without the loss of energy entailed in blowin olf excess fluid from the discharge line, an it is to be understood that while the resent showin and descri tion discloses on y certain specia fied modi cations of the invention, other forms and modifications are included tin the spirit and scope of the invention as expressed in the claims. j

What I claim.is:- v 1. In combination, a centrifugal4 compressor, a driving engine therefor, a com presser discharge line, a check valve in said discharge line, a controlling valve for said eni gine, and means to o erate said controlling valve by discharge ine pressure and the speed of the engine comprising a liuidcon-l duit leading from said discharge line between said compressorand Said check valve.

2. The combination `With compressor having a dischargeline, and an engine for said compressor, cfa check valve in said discharge line, 'a controlling valve for said engine, a speed governor and a motor for operating said controlling valve, a

a centrifugal ioo fluid conduit for transmitting the ressure r of said discharge line to operate sai means in said conduit for allowin free passage of the fluid through said con uit in a direction to close said valve and means; fo'r.

restricting the flow in the opposite direc ion. In testimony whereof, I have hereunt set my hand. Y

OTTO BANNER. Witnessesz F. G. RAUnn, F. A. Porn.

motor,

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