US2841236A - Manifold type pulsation dampeners - Google Patents

Description

July 1, 1958 N. H. MOERKE 2,841,236

MANIFOLD TYPE PULSATION DAMPENERS Filed June 10, 1955 6a: F/an J5 w J4 J5 15' 13 1 J4 I J4 INVENTOR.

M0 .15 Mozezz United States Patent 2,841,236 MANIFOLD TYPE PULSATION DAMPENERS Ned H. Moerke, Paola, Kans., assignor to The Fluor Corporation, Ltd, Los Angeles, Calif., a corporation of California Application June 10, 1955, Serial No. 514,609 6 Claims. (Cl. 181-40) This invention has to do with improvements in pulsation dampeners for use as applied principally, though typically, to natural gas, refinery gas and chemical plant gas piston type compressors, which operate at relatively low frequencies to compress the gas frequently to pressures ranging in excess of 1,000 p. s. i. More specifically, the invention relates to improvements in the general type of pulsation dampeners disclosed in the Stephens Patents Nos. 2,405,100, 2,437,446 and 2,501,794.

Preliminarily it may be observed that the condition to be corrected by the use of pulsation dampeners as applied to gas compressors, is the elimination at either or both the suction and discharge sides of the compressors, of pulsations or pulse waves created in the gas stream by the low frequency suction or compression eiiects of the pistons. Usually the problem is encountered where gas stream pulsations are created by multiple cylinder gas compressors, in which each piston and cylinder individually creates a pulsative condition, and where the combined effects of the individual pistons and cylinders are contributory to a composite or total pressure pulsation effect existing in the suction or discharge manifolds. Heretofore the'practice in dampening the pulsation effects created by a multiple cylinder compressor, has been to manifold the cylinders and to provide a pair of chambers interconnected by an elongated inductance, all the cylinders drawing from or discharging into a common chamber, depending upon whether the dampening equipment is applied to the intake or discharge side of the compressor. It has also been proposed to dampen the pulsative efl ects created by an individual piston and cylinder, by connecting individually thereto a dual chamberinterconnecting inductance type of dampener.

The present invention is directed specifically to improvements to dampeners which are of a manifold type in that plural compressor suction or discharge nozzles, as the case may be, are connected to and discharge into a single elongated shell. However, the invention departs from conventional manifold dampeners in that it approaches the problem of most eifectively dampening the compressor intake or discharge not by drawing from or discharging into a chamber common to all the connected cylinder nozzles, but by direct connection of the nozzles with individual or respective chambers. While these may communicate through individual and respective inductance pipes or passages with a common second capacitance chamber, the overall effect is to accomplish essentially individual acoustical filtering of the pulsations created by the individual pistons and cylinders, as compared with and to better efiiciency than pulsation elimination by acoustically filtering the combined pulsative effects of the several pistons and cylinders, as where all connect directly with the common chamber.

The invention has for its general object to provide for the most practical and economical construction of a dampener as characterized above, which need require only a single overall shell applicable to the compressor in physical resemblance to a manifold, and which therefore has the advantage of minimum space requirements together with minimum material and fabrication costs.

In accordance with the invention, the dampener components are accommodated in a single and elongated shell the interior of which is divided to form a plurality of chambers individually connected to the compressor cylinder nozzles, and individually communicating with a common secondary or outlet chamber by way of individual inductance passages formed by a corresponding number of elongated pipes contained withinthe shell and extending within the chambers in the unique arrangement later described.

In speaking of the provision within the shell of individual chambers directly connected to the compressor nozzles, it is recognized that in some instances, depending upon the design and performance characteristics of the compressor it may be possible or desirable in some instances to connect one of the chambers with a pair of the compressor nozzles, but with less than all the nozzles. To illustrate, design conditions may require for best results in some instances, connection of all four nozzles of a four cylinder compressor with four individual chambers in the dampener shell, whereas in another instance adequate dampening may be realized by connecting two pairs of the nozzles with two chambers in the dampener shell. In either instance, however, provision for the length of acoustical inductance interconnecting these chambers with a common secondary chamber necessitates for those installations contemplated by the invention, extending the inductance passage pipes in return bend forms contained in not only the capacitance chambers which they acoustically interconnect, but at least one third chamber.

Accordingly, the invention is concerned essentially with the described multiple chamber and nozzle arrangement, together with the accommodation of the interconnecting inductance pipes in a manner such that one or more of the latter are enabled to have their required lengths, by extending the pipe or pipes in return bend form within chambers other than those which they acoustically interconnect.

The invention will be understood more clearly and to best advantage from the following detailed description of the illustrative embodiment shown by the accompanying drawing, in which:

Fig. l is a view showing a dampener assembly connected to a compressor discharge nozzle series, including typically four nozzles, two pairs of which discharge into individual chambers;

Fig. 2 is a similar view showing individual chambers in the dampener shell connected respectively to a corre- 'sponding number of the compressor nozzles; and

Fig. 3 shows a further variational form of the invention.

It will be understood that the illustrated dampener designs are applicable interchangeably to compressor intake and discharge nozzles. The drawings show the dampener connections to be with the compressor discharge nozzles. The same showings are illustrative of intake dampener arrangements, assuming the gas flow arrows to be reversed.

Referring first to Fig. l, the dampener assembly, generally indicated at ill is shown to comprise an elongated cylindrical shell 11 having a gas outlet nozzle 12, and inlet nozzle 13 connected at 14 to the discharge nozzle 15 of a gas compressor 16. Here the shell 11 is shown to be divided by partitions 17 and 18 into substantially equal volume chambers 19 and 20 each of which receives the pulsating gas discharge from a respective pair of the compressor nozzles 15. The shell contains a third chamber 21 which may correspond substantially in vol- 3 time with the volume of either of the chambers 19 or 20.

The pulsating gas streams discharged by the compressor into chamber 19, pass into chamber 21 through an open ended elongated inductance pipe 22 extending through the partitions 1'7 and 33 and through chamber 21, 'the pipe wall between the pipe ends being imperforate. The gas entering chamber 29 passes into chamber 21 through a similar pipe 23 corresponding in length to pipe 22. Reference may be had to the Stephens patents referred to in the foregoing for formulations prescribing the sizes or volumes of chambers and 231 (or 20 and 21) and the length of pipes 22 and 23 in relation to such various factors as the fundamental frequency of the compressor, the gas pressure and speed of sound in the gas. For present purposes it will suffice to state that the known design requirements necessitate pipes 22 and 23 of extended length, and which normally will be accommodated terminally within the dimensions of chambers 19 and 21, and int-ermediately by the length of chamber 29. Due to the desirability of minimizing the required overall length of the shell 11, in the interest of saving space and materials, a problem has arisen relative to making an acoustical interconnection of chambers 28 and 21, by reason of the limitation in their practicable lengths. In accordance with the invention, I am able to obtain the length required of pipe 23 through which the gas in chamber 20 flows directly into chamber 21, by so extending the pipe as to occupy to the length necessary, chamber 19. Thus pipe 23 is shown to have an intermediate return bend portion 22a extended into chamber 19, the pipe thence running through chamber 20 to discharge into chamber 21.

In Fig. 2 the typically four compressor nozzles 24 are shown to connect individually through nozzles 25 of the dampener shell 26, with respective chambers 27, 28, 29, and 3h separated by partitions 31 welded into the shell. Chamber 30 is divided by partition 32 from a common secondary chamber 33 from which the gas flows to the discharge nozzle 34. Here the several inductance pipes interconnecting individually the chambers 27 to 30 with chamber 33, may be made of about equal length and are accommodated to their required lengths within the shell substantially as illustrated. Pipe 35 extends directly from chamber 27 through the other primary chambers into chamber 33. Pipe 36 is shown to extend from chamber 28 by return bend at 36a within chamber 27, through the chamber series into chamber 33. Similarly pipe 37 has a return bend extending from chamber 29 within chamber 28 and thence to the second-.

ary chamber. Finally, pipe 38 is shown to extend from chamber 3% through chamber 29 to a reverse bend at 38a in chamber 28; and thence into chamber 33.

Fig. 3 is illustrative of an adaptation of the invention to compressors having an odd number of cylinders, typically five. The dampener shell 4t? may be divided into individual chambers corresponding in number to the nozzles 41 and the individual chambers connected by respective inductance pipes with a common discharge.

bers separately communicable through their respective inductance pipes with a common discharge chamber.

The manifold type dampeners described in the foregoing will be recognized as affording the distinct advantages of isolating one or more compressor cylinders from the pulsation eifects produced 'by adjacent one or more cylinders. In all instances pulsation eliminating eftects occur to greater effectiveness by virtue of the connection of individual cylinders, or individual groups of cylinder only through a series of acoustical capacitance volumes and inductance tubes connecting with a common discharge chamber, all to the end result and advantage of preventing the adverse efiects of pulsations from certain cylinders acting uponan adjacent cylinder or cylinders.

I claim:

1. A pulsation dampener comprising an elongated cylindrical shell, transverse partitions dividing the shell into first and second chambers each connectible through side openings in the shell with difierent gas compressor cylinders and also dividing the shell into an additional chamber containing an opening for passage of gas flowing through the shell between said side and chamber openings, said second chamber being between said first and additional chambers, an elongated pipe connecting said additional chamber with said first chamber, and a second elongated pipe connecting said additional chamber with said second chamber and having a return bend portion within the first chamber, each of said pipes extending completely through one of said first and second chambers and through both said partitions.

2. A dampener as defined in claim 1, in which said pipeshave substantially equal length.

3. A dampener as defined in claim 1, in which said first and second chambers are about equal volumeand said pipes are substantially equal length.

4. A pulsation dampener comprising an elongated cylindrical shell, transverse partitions dividing the shell into first, second, third and fourth chambers each connectible through side openings in the shell with different gas compressor cylinders and also dividing the shell into an additional chamber containing an opening for passage of gas flowing through the shell between said side and chamber openings, an elongated pipe connecting said additional chamber with said first chamber, a second pipe connecting said additional chamber with said second chamber and having a return bend portion in said first chamber, a third pipe connecting said additional chamber with said third chamber and having a return bend portion in said second chamber and a fourth pipe connecting-said additional chamber with said fourth chamberand having a return bend end extent within both said second and third chambers.

5. A dampener as defined in claim 4, in which all of said pipes are of substantially equal length.

6. A dampener as defined in claim 4, in which said first, second, third and fourth chambers have about-equal volume and all said pipes have substantially equal length.

References Cited in the file of this patent UNITED STATES PATENTS 2,707,033 Moerke et al Apr. 26,

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