US3447557A

US3447557A - Surge chamber

Info

Publication number: US3447557A
Authority: US
Inventors: Morton E Phelps
Original assignee: PHELPS FAN Manufacturing CO Inc
Current assignee: PHELPS FAN Manufacturing Co Inc
Priority date: 1967-02-10
Filing date: 1967-02-10
Publication date: 1969-06-03
Anticipated expiration: 1986-06-03

Description

June 3, 1969 M. E. PHELPS ET AL 3,447,557

SURGE CHAMBER Filed Feb. 10, 1967 II 0 n 1 4/; II II. I! I! INVENTORS. M0870 5 PA/l PS,

& a 5 O. W W m United States Patent Oihce 3,447,557 Patented June 3, 1969 Tommy 0. Bell, P.0. Box 203, Hallsville, Tex. 75 650 Filed Feb. 10, 1967, Ser. No. 615,195 Int. Cl. E03b /00 US. Cl. 137-207 6 Claims ABSTRACT OF THE DISCLOSURE A surge tank, for smoothing pressure changes in a pumped liquid, having a continuous curved wall with a liquid inlet therein and a tengential feed conduit connected to the inlet causing the entering liquid to rotate about the curved wall trapping air in the top of and centrally of the tank. A tank outlet is arranged to exhaust liquid from the peripheral area near the bottom of the curved wall so as to prevent loss of trapped air from the center of the tank. Desirably an inner chamber is disposed within the tank, and is also closed at the top but has communicating openings near its bottom to permit entry of both air and liquid from the tank to the inner chamber, Thus, dual air trapping, compression chambers are provided to assist the swirling liquid in eliminating pressure variations at the liquid outlet.

This invention relates to surge chambers and more particularly to an improved surge tank utilizing both the rotation, or spinning, of a liquid and the compression of air, preferably in at least two chambers, to absorb shocks and smooth out pressure variations of a pumped liquid.

Surge tanks as presently known have many applications including the absorption of irregularities of flow in main liquid supply lines, the smoothing out of pumping pressure variations where water is pumped at high pressures for spraying vegetation, fruit orchards and the like, and the spraying of disinfectants onto crops.

It is a primary object of the present invention to provide an improved surge chamber which operates to spin the entering liquid and trap air above the spinning liquid both serving to smooth pressure variations of the incoming liquid.

Another object of the invention is to provide a surge chamber, having the above described characteristics, which is so constructed as to avoid losing air trapped above the spinning liquid.

An important object of the invention is to provide at least two air trapping chambers which augment each other and the spinning liquid to iron out pressure surges.

A further object of the present invention is to provide an improved surge chamber, having the above described characteristics, which employs no moving parts.

Yet another object of the invention is to provide an improved surge chamber which is of simple construction, easy and economical to manufacture, and eflicient in operation.

The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawing, wherein like reference characters indicate like parts throughout the several figures and in which:

FIG. 1 is a vertical axial sectional view of an improved surge chamber according to the present invention;

FIGS. 2 and 3 are horizontal sectional views taken on lines 22 and 3-3, respectively, of FIG. 1, and looking in the direction of the arrows;

FIG. 4 is a vertical axial section of another embodiment of the invention; and

FIG. 5 is a vertical sectional view similar to FIGS. 1 and 4 of still another embodiment of the invention.

Referring more particularly to the drawings, in FIGS. 1-3 is illustrated a preferred embodiment of the invention as comprising a surge chamber 10, or tank, formed of metal such as aluminum, brass, or any other suitable common noncorrosive, metal or alloy. Tank 10 has a cylindrical sidewall 12 integrally bonded to a continuous top wall 14, and a bottom wall 16 in which is an outlet 18. In the sidewall is an inlet 20 positioned considerably below the top wall and somewhat above the bottom wall. Integrally bonded to the inlet is a liquid feed conduit 22 disposed at a tangent to the cylindrical inner surface of the sidewall so that entering liquid under pressure will swirl around the inner surface of the sidewall. This rotational movement within the chamber, by centrifugal force, throws the liquid against the sidewall so that air is trapped under the top wall, the surface of the liquid within the chamber taking an inverted conical shape, not shown, whose slope depends upon the speed of rotation. Swirling of the liquid forces the trapped air toward the center of the chamber and against the outer surface of an inner cylindrical tube 24 integrally bonded to the top wall. The cylindrical tube 24 and the top wall form an inner chamber 26 which communicates with the outer chamber, represented by the reference character 28, by a purality of spaced openings 30 positioned at the lower part of the tube 24 between its bottom and the level of the inlet 20.

A second wall 32 is spaced above the bottom wall 16 and is of smaller diameter so that a space 34 is provided at its periphery to permit egress of liquid downwardly along the inner surface of the sidewall 12. In the space between the first and second bottom walls are disposed a plurality of curved vanes 36 which extend from the periphery of the second bottom wall at least to and slightly within the periphery of the outlet 18. The vanes are curved in such direction as to smoothly lead exiting liquid from the space 34 to the outlet 18 guiding such liquid at the start in the same direction as its rotation, but with greater curvature so as to gradually turn the liquid toward the center of the surge chamber and into the central outlet. Thus, a path exists, for the discharge of liquid through space 34 under the second bottom wall 32 and along the vanes 36, which is so arranged as to be completely spaced from the central portion of the surge tank 10 and the centrally disposed air trapped therein.

The operation of the surge chamber is as follows. Liquid from a pump is forced at high pressure along the feed conduit 22 and enter the surge tank through inlet 20 spinning about the outer chamber 28. As the angular velocity of the liquid increases with surges in pump pressure, the liquid within the outer chamber 28 rise and is held against the sidewall 12 by centrifugal force, the upper surface of the liquid adopting the form of an inverted cone. As pressure builds up during such surges, the air within both

chambers

26 and 28 is forced to the top, and in the outer chamber takes the same conical shape as the liquid and is pressed inwardly against the central cylinder 24. With extremely high pressure surges some air escapes from the top of the outer chamber 28 descending along the inner cylinder 24 where it pases through the apertures 30, floats to the top of liquid in the inner chamber 26, and remains trapped therein. During this course of movement, the air in both chambers is kept away from the exit space 34 and cannot escape the surge tank. The rotating liquid, however, in the outer chamber 28 descends through the space 34, encounters the guide vanes 36 which slow its momentum and discharges through the outlet 18. Surges in pressure at the inlet 20, first compress the air in the outer chamber 28 before afiecting the air in the inner chamber 26. However, very rapidly the force of the surge is transmitted from the outer chamber to the inner chamber until a balance is achieved.

The described operation, it will be noted, utilizes three factors in absorbing pressure surges. First, part of the momentum of the entering liquid is absorbed in the rotation of the liquid around the outer chamber 28. Second, the increased pressure and volume of the surges compress air at the top of the outer chamber 28. Third, the pressure and volume of surges are absorbed by compressing air in the upper part of inner chamber 26. The compression of air in a single chamber to absorb shock for smoothing out the pressure of a pumped liquid is well-known. The novel spinning of the liquid and its combination with air compression in a plurality of chambers, however, greatly increase the efficiency of the device.

The spinning of the liquid has a flywheel effect in smoothing out the pressure changes. This may be explained as follows. The velocity of a liquid surge as it enters the outer chamber will cause energy to be imparted to the liquid already spinning in said chamber and will cause a greater velocity to be imparted to the liquid rotating against the inner surface of the sidewall 12. Thus, the spinning liquid first receives energy and then, when the surge pressure decreases and the liquid slows down, imparts energy to liquid discharging from the outlet. Stated in another way, the kinetic energy of the incoming liquid is first stored in the rotating liquid and then released. Part of the kinetic energy is converted to potential energy as it enters the spinning liquid. The converted potential energy is absorbed by the air in both the inner and outer chambers for later release on reduction of pressure of the incoming liquid.

The embodiments illustrated in FIGS. 4 and 5 differ in only a few respects from the embodiment shown in FIGS. 1-3. Accordingly, the same reference numerals are used where the parts are identical, and slightly modified parts are referenced by the same numeral primed. Since all three embodiments operate in the same manner, only the differences in structure will be described herein.

The embodiment of FIG. 4 is preferably constructed entirely of aluminum, the cylindrical outer wall 12' being welded at 38 to a dome-shaped top wall 14', and at 40 to a concave bottom wall 16'. The outlet nipple 18' is also connected to the bottom wall by welding as at 42. Similarly, the inner tube 24 is welded at is lower edge 44 to the second bottom wall 32, the guide vanes for discharging liquid being omitted. In the inner cylinder 24', apertures 30' are fewer in number, but individually larger in area than the corresponding apertures 30 of the FIG. 1 embodiment. The surge tank of FIG. 4, therefore, is a very strong metal tank capable of withstanding higher pressures, and yet is easily fabricated.

The FIG. 5 embodiment is intended for use with liquids being pumped at lower pressures, and is formed entirely of any suitable plastic material. The outer chamber 28 comprising sidewall 12", top wall 14" and inner cylinder 24" are molded in one piece. The sidewall 12" at its lower end is threaded as at 46 for connection to a separate, molded cup-shaped, bottom wall 16". The bottom wall may have integrally formed therein, as by molding, a series of vanes 36" which serve as a seat for the second bottom wall 32", which has a circular protrusion 48 on its underside for fitting in the opening formed by the vanes 36". Wall 32" may be firmly secured to vanes 36" by cement or by a friction fit. In this manner the second bottom wall 32" is supported from the bottom of the tank, and the unit is easily assemblied by then threading the bottom 16" onto the threads 46 of sidewall 12". Desirably the cylinder 24" is thickened in the upper portion 50 where it merges into the top wall 14". The spacing 30" between

parts

24 and 32" replaces the plurality of openings 30 for communicating the chambers 26' and 28'.

It should be noted that the above described surge tanks have the following advantages. The entrance of liquid on a tangent to the outer cylindrical wall through a property-sized inlet creates the greatest possible rotating speed of the liquid within the unit. Thi rotation creates a suction at the inlet which helps to overcome reverse flow, or reduction in pressure. Rotation of the liquid within the unit creates a source of potential pressure which evens out the pressure surges between the inlet and outlet. The air trapped in both

chambers

26, 28 is under pressure which is applied to the liquid at the bottom of the surge tank to assist in smoothing out the discharge flow, part of the pressure increases being absorbed in the air chambers and subsequently released during the low pressure portions of the pumping cycle. The use of two chambers, or more, for trapping air permits an interaction, the outside chamber first absorbing a shock without having to overcome the weight of all of the liquid in the unit. As the spinning liquid is already in motion in the outer chamber, it will rotate faster and move upwardly in the outer chamber with small changes in force, or pressure. The air in the inner chamber absorbs the force from the outer chamber at a slower rate, but with the result that a surge in pressure is more fully absorbed and both chambers act to smooth out pressure variations by imparting pressure to the discharging liquid when the incoming liquid pressure dro s. Since the liquid is being effectively discharged from the outside edge of the rotatng liquid, loss of air located in the middle of the outer chamber is prevented. The rotation of the liquid serves to keep the air away from the discharge path at the outside of the outer chamber. The inlet and outlet being at different levels permits the draining of the surge chamber when air is introduced into the inlet. Construction of the unit may be one-piece, as shown in FIGS. 1-3, since maintenance and internal servicing is unnecessary. The inner chamber prevents liquid which is entering the inlet from disturbing the cone of air in the center of the outer chamber. It also helps to keep the moving liquid in a smaller annular area which, in turn, increases the speed of rotation. A plurality of trapping chambers are provided and air is kept trapped in these chambers without the aid of pistons, diaphragms or balloons, as commonly used in certain conventional apparatus.

If desired, the device may be constructed without the inner cylinder 24 and the second air chamber 26. The unit thus modified will operate, however, with less efficiency.

Although certain embodiments of the invention have been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

What is claimed is:

1. A surge tank for moothing pressure changes in a pumped liquid, comprising an outer chamber having an arcuate, continuous sidewall, a top wall closing the outer chamber for trapping air, a bottom wall having a liquid outlet disposed centrally therein, a second bottom wall in said chamber spaced above said first bottom wall and having its periphery spaced from aid arcuate sidewall, and liquid feed means directed tangentially to said arcuate wall and connected to an inlet therein spaced considerably below said top wall and somewhat above said first bottom wall, whereby liquid entering said inlet is caused to swirl about said arcuate wall, trapping air centrally of said chamber, both said swirling liquid and trapped air contributing to smooth out pressure changes of the entering liquid, and said swirling liquid in the 5 chamber exiting to said outlet through the space between the second bottom wall and the sidewall.

2. A surge tank according to clam 1, wherein a plurality of curved vanes are disposed vertically between said first bottom wall and said second bottom wall and extending from the periphery of said second bottom wall to the periphery of said outlet, whereby to direct liquid inwardly from the periphery of the second bottom wall to said centrally disposed outlet.

3. A surge tank according to claim 1, wherein an innerchamber is disposed within the outer chamber defined by said side, top, and bottom walls, said inner chamber being completely enclosed except for at least one opening provided near its bottom communicating with said outer chamber, whereby liquid and air may enter said inner chamber, the air trapped in said inner'chamber assisting in the smoothing out of pressure changes of liquid entering said inlet.

4. A surge chamber in accordance with claim 3, wherein said inner chamber comprises an arcuate, continuous sidewall having a common axis of curvature With said sidewall of the outer chamber, the sidewall of the inner chamber being closed at its top by said top wall of the outer chamber.

References Cited UNITED STATES PATENTS 2,671,652 3/1954 McCullough 139-26 XR 3,082,784 3/1963 McMath 137207 3,146,796 9/1964 Everett 137-207 XR 3,292,661 12/1966 Everett 137--207 XR BILLY S. TAYLOR, Primary Examiner.

US. Cl. X.R.