US2273766A

US2273766A - Water hammer arrester

Info

Publication number: US2273766A
Application number: US351412A
Authority: US
Inventors: Jr Edwin B H Tower
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-08-04
Filing date: 1940-08-04
Publication date: 1942-02-17
Anticipated expiration: 1959-02-17

Description

Feb. 17, 1942.

E. B. H. TOWER, JR

WATER HAMMER ARRESTER Filed Aug. 4, 1940 2 Sheets-Shed 1 a E .F

Feb. .17, 1942. as. H, TOWER, JR WATER HAMMER ARRES'I ER Filed Aug. 4, 1940 2 Sheets-$heet 2 TIME m sncou'ns AFTER cLusuRE 0F QUICK ACTING VALVE 0N TEST PIPE 5 5. w mm ,W u Mm A, EFY. 2 ?v 2 V T ETC .1 PFU U-Umw bV m 5 5 w. wm w mflm GB mm PS1... W 9 CT 4 Mmm PG? 3 5 v v m n o a w a A .L A i 0 m m .m A 1, o dun! a mmmm 5 mmzzmmpfis on. E5 m n mu @335 E $555.8 H3535 mm m Patented Feb. 17,- 19s.!

I WATER HAMMER Annns'rnn Edwin B. H. Tower, Jr., Milwaukee, Wis. Application August 4', isiaser'iai No. 351,412

4 Claims. (01. 138-30) The invention relates to a water hammer arrester or other energy absorbing appliance of the type in which abnormal impulses or fluctuaor other conduit are suppressed by compression of a gas or other compressible fluid medium to prevent water hammer.

When water or other liquid which is in transit under pressure through a pipe or other con duit is brought to an abrupt stop by closing a valve, periodic surges in kinetic energy are propagated in the water and oscillatein recurring cycles through the water between the valve and the source of pressure until the energy is dissipated. 1 v

These periodic surges in energy causeabnormal impulses or fluctuations in pressure of such order as to produce violent concussion, called water hammer, which subject the pipe and its joints to enormous stresses and produce loud bangs-or other objectionable noises.

' tions in pressure of water or other liquid in a pipe When water hammer occurs, the pipe and its I joint are liable to burst or rupture, and appliances connected" to the pipe are injured or damaged.

In order to suppress the abnormal impulses liable to be or fluctuations in pressure to a sumclent extent to prevent water hammer, energy must be absorbed from the water at a sufficient rate to cause a substantial reduction in the rate of -variation of the pressure of the water throughout the surges in energy and thereby impose such limitation upon the impulses or fluctuations in pressure as to prevent water hammer.--'

Appliances have been proposed in which a casing encloses a chamber partitioned by a plicated bellows into an-expansion compartment 1 to receive water from a pipe and a compression compartment to confine a gas or other compressible fluid medium, but such appliances lack ability to compress at a suflicient rate such mass arrester which is small in size relative to its of gas as is required; to suppress to a sufficient extent throughout, the surges in energy the im' pulses or fluctuations in pressure causing water to en-v hammer. I

These appliances further lack ability sure to a suiilcient extent to prevent water ham- I mer.

Another object is to provide a water hammer arrester which will increase the rate of absorption of energy from the water over the rate 0!" absorption of energy by compression of the compressible; fluid confined within the compression compartment. Another object is to provide a. water hamme arrester in which the bellows will act upon the water upon increase in the pressure thereof to' effect a substantial increase in the absorption .of energy therefrom.

Another object is to provide a water hammer arrester in which'the bellows will be guided .by the casing and substantial'energy will be absorbed by displacement of fluid between the bellowsand the casing.

Another. object is to provide a water hammer arrester which will dissipate to a substantial extent. the energy absorbed in suppressing the impulses or fluctuations in pressure and thereby diminish'the magnitude of each succeeding impulse or fluctuation in pressure and accelerate the dissipation oi the entire energy. I

Another object is to provide a water hammer arrester, in which the bellows will require less deflection to cause suflicient energy to be absorbed to'prohiblt water hammer.

Another object is to provide a water hammer arrester which will endure innumerable shocks in absorbing energy to suppress the impulses or fluctuations in pressure causing water hammer. Another object is to provide a water hammer arrester which. will protect a pipe and its joints from impulses or fluctuations in pressure that are liable to burst or rupture the pipe and its joints and injure or damage appliances connected to the pipe. 7

Another object is to provide a water hammer capacity to absorb and dissipate energy.

Another object is to provide a water hammer arrester which maybe arranged in any position inrelation to the pipe to receive water there from. 1

' Another object is to provide a water hammer dure the shocks imposed upon the bellows by the Y impulses and fluctuations in pressure ofthe water in the expansion compartment.-

The present invention has for. its object to provide awater hammer arrester which will possess permanent capacity to absorb energy at a suflicient rate throughout'the surges in energy to suppress, the impulses or fluctuations in pres.-

arrester which is inexpensive to manufacture and install .and which does not require attention in service.

Another object isto provide 'a water hammer arrester which is simple in construction and durable and emcient in service.

According to the present invention as it is ordinarily embodied in practkc, the bellows is the casing to guide the bellows upon deflection thereof and form constricted passages between the bellows and the casing of an order to throttle displacement of fluid between the bellows and the casing to absorb energy from the pressure fluid upon deflection of the bellows by the impulses in pressure.

When the bellows is contracted by the water within the expansion compartment, the water in the annular pockets between the plaits isdisplaced through the constricted passages between the plaits and the casing and thereby the rate of absorption of energy from the water is increased to diminish the ultimate rise in pressure during the surges in energy.

The present invention is applicable in particular to a water hammer arrester in which a casing ispartitioned into an expansion compartment and a compression compartment by a plicated metallic bellow which will deflect within its elastic limits to compress a suflicient mass of compressible fluid or medium to absorb energy at a suflicient rate to prohibit water hammer.

The compressible fluid or medium confined within the compression compartment is ordinarily a permanent foam so as to increase the rate of absorption of energy in relation to the deflection of the bellows;

Although the invention is described herein as applied to prevent water hammer caused by impulses or fluctuations in the pressure of water, it is applicable to prevent water hammer caused by impulses or fluctuations in the pressure ofoil or other liquid, and the term "water hammer" as employed herein denotes and comprehends water hammer caused by any fluid or liquid.

The water hammer arrester shown in the accompanying drawings exemplifies the invention as embodied in practice, and the views in these hammer arrester at the lower part with the bellows contracted by the initial impulse or fluctuation in pressure.

Fig. 4 is a chart depicting by a curve the impulses or fluctuations in pressure causing water hammer and another curve the impulses or fluctuations in pressure as suppressed by the water hammer arrester shown in the drawings.

The water hammer arrester is provided with a cylindrical casing I having an integral dome '2 at the top and a removable base 3 at its bottom.

The base has a peripheral flange 4 screwthreaded to thecylinder and a central inlet 5 surrounded by a collar 6.

The casing'is partitioned by a plicated metallic bellows I into an expansion compartment 8 to receive water or other liquid through the inlet 5 and a compression compartment 9 to confine a gas or other compressible fluid and mineral oil or other incompressible fluid. I

The bellows is supported within the casing by a head l0 having an integral post H passing through a tapered aperture in the dome Zand having. a tapered section l2 intermediate its ends to bear in the tapered aperture.

The postisprovided upon its upper end with a nut 14 screw-threaded thereon todraw its ta- 1 provided with plaits fltting close to the walls of pered section into the tapered aperture and thereby retain the head in a fixed position.

The bellows is composed of annular metallic disks l5 which are united-to each other at the inner and outer perimetersinalternation by flanges l6 formed on the disks'and brazed or otherwise fastened in grooves. H in the disks.

The bellows is thus provided with plaits forming alternate internal and external elongated pockets.

The top disk has its flange brazed or otherwise fastened in a groove'in the head Ill, and the bottom disk is closed at itscenter by-a cap i9 brazed or otherwise fastened thereto.

'The compression compartment contains a gas or other compressible fluid and a mineral oil or other incompressible fluid, and the mineral oil occupies about one-half /2) the volumetric capacity of the compression compartment.

The gas and the mineral oil are intermingled with each other by agitation to form a foam or emulsion throughout the entire compression compartment, and such foam is stabilized by a small quantity of tincture of quillaja or other foam stabilizing agent mixed with the mineral oil.

The mineral oil is introduced into the bellows through an aperture in the cap on the bottom disk, and then the aperture is sealed by solder.

The bellows is of such size as to provide a compression compartment with suflicient volumetric capacity to contain the mass of gas and mass of oil required to enable the water hammer arrester to be efiective in preventing water hammer under the conditions to which it is subjected in practice.

The bellows is further made deflectable within the range of its elastic limits to effect suflicient variation in the volumetric capacity of the compression compartment to compress the gas to absorb suflicient energy from the surges in energy to prevent water hammer.

- The mass of the oil is limited to render its inertia insuflicient to impede the compression of the gas to any substantial extent or necessitate employing a bellows of such length that it will be distorted or buckled intermediate its nds upon compression.

The water hammer arrester is shown applied to prevent water hammer in a pipe 20 having a valve 2i to stop the flow of water or other liquid through the pipe.

The casing is connected to the pipe near the valve to admit water or other liquid from the pipe into the compression compartment.

When the flow of water through the pipe is brought to a sudden stop by closing the valve, surges in energy are propagated in the water in the pipe and tend to produce abnormal impulses or fluctuations in pressure of the order causing water hammer.

Inasmuch as the magnitude of the impulses or fluctuations in pressure depends upon the size of the pipe andthe rate of flow of water in the pipe at the instant the valve is closed, the mass of gas in the compression compartment is proportioned according to these conditions.

That is, the gas has its mass proportioned to absorb uponvariations in its compression by variations in the pressure exerted by the water in the expansion compartment, suflicient energy from the surges in energy to cause such reduction in the rate of variation in the pressure of the water in the v expansion compartment throughout the surges in energy as to impose a aavavce "3 sumcientlimitation upon the impulses or fluctuations in pressure to prevent water hammer.

The gas has its compression relative to the variation in the volumetric capacity of the compression compartment amplified by the oil. to 5 effect suflicient compression of the gas upon deflection of the bellows within .therange oi-rits elasticlimits to prevent water hammer. But the oil has its mass limited to render its inertia insufliicent to cause any substantial difl'erence between the rate of variationin the compression of the gas in the compression compartment and the rate of variation in the pressure exerted bythe water in the expansion compartment. v 5

*I'he bellows is provided with plaits forming annular pistons fitting close to the chamber within the casing to guide the bellows upon deflection thereof and form constricted passages between the plaits and the walls of an order to throttle displacement of fluid from the external pockets between the pistons to absorb energy from the fluid within the compression compartment upon deflection of the bellows by impulses in pressure.

When thebellows is contracted the water is displaced from the pockets between the plaits and through the constricted passages to absorb energy from the water and thus reduce the ,amplitude and magnitude of the impulses or fluc- -tuations in pressure.

The chart. shown in Fig. 4 .depicts by a curve a v the abnormal impulses or fluctuations in pressure tending to be produced by the surges in energy propagated upon the sudden stoppageof the 5 flow of water through the pipe by closing the I valve under thefollowing conditions:

Pipe three-quarters inch in diameter, one

hundred and fifty (150) feet long from source of pressureto valve.

' Static pressure of waterin pipe with valve closed, about fifty (50) pounds.

Flow pressure of water through pipe with valve open, about five (5) pounds.

Rate of flow of water about ten (10) feet per second.

, Pressure of initial impulse or fluctuation in pressure about six hundred (600) pounds. Duration of initial impulse or fluctuation in pressure one-fifth (V5) second.

When a water hammer arrester, such as described herein and shown in the drawings, is provided with a bellows containing about fifteen (15) cubic inches of air and'about fifteen (15) cubic inches of oil, and having its dimensions about three (3) inches in diameter and about twelve (12) inches in length expanded and about six (6) inches in length contracted, the initial impulse or fluctuation in pressure is reduced by compression of the air in the compression compartment to about two hundred (200) pounds,

- as indicated by the curve b.

The pressure of the initial impulse or' fluctuation in pressure is further reduced, as indicated 'by curve c, upon contraction of 'the bellows by.- the energy absorbed in. displacing the water from the pockets between the plaits inthe bellows and through the constricted passages between the, plaits and the casing.

Inasmuch as energy is absorbed from the water 7 by its displacement through the constricted passages between the bellows and the casing, the bellows requires less deflection than would otherwise be required to cause suflicient energy I to be absorbed-to prohibit water hammer. 7 5

The invention described and claimed herein may be applied in various ways for different purposes to absorb energy from water or other fluids subject to impulses or fluctuations in pressure.

The water hammer arrester may be modified V in its proportions according to the energy it is required to absorb and the conditions under which it is to operate.

The invention exemplified by the water hammer arrester described herein and shown in the drawings may assume various embodiments which will be within its scope as defined by the claims. I

' i The invention described in the foregoing speciflcation and shown in the drawings forming a part thereof, is hereby defined and claimed as follows:

1. An energy absorbing appliance for suppressing water hammer or. similar purposes, comprisingin combination, a casing enclosing a cylindrical chamber and having an inlet to admit pressure fluid subject-to impulses in pressure, a plicated metallic bellows arranged within said casing to partition said chamber into an expansion compartment to receive said pressure fluid and a sealed compression compartment to con.- tain a compressible fluid to absorb energy from said pressure fluid and said bellows having its plaits forming annular pistons fitting close to the walls of said chamber to guide said'bellows upon deflection thereof and form constricted passages between said plaits and said walls of an order to throttle displacement of fluid from the external pockets, between said pistons to absorb energy from said pressure fluid, upon deflection of said bellows by said impulses in pressure, and a compressible fluid confined within said sealed compressioncompartment to absorb energy from said pressure fluid upon its impulses in pressure to limit the amplitude of its fluctuations in pressure.

2. An energy absorbing appliance for suppressing water hammer or similar purposes, comprising in combination, a casing enclosing a cylindrical chamber and having an inlet to admit pressure fluid subject to impulses in pressure, a plicated metallic bellows arranged within said casing to partition said chamber into an expansion compartment to receive said pressure fluid and a sealed compression compartment to contain a compressible fluid to absorb energy from said pressure fluid and said bellows being composed ofannular disks spaced apart from each other and joined together at the inner and outer perimeters thereof in alternation by flanges formed thereon and said disks forming annular pistons fltting close to the walls of said chamber to guide said bellows upon deflection thereof and form constricted passages between said disks and said walls of an order to throttle displacement of fluid from the external pockets between said pistons to absorb energy from saidpressure fluid upon deflection of said bellows by said impulses in pressure, and a compressible fluid confined within said sealed compression compartment to absorb energy from said pressure fluid upon its impulses in pressure to limit the amplitude of its fluctuations in pressure.

8. A water hammer arrester, comprising in combination, a casing enclosing a cylindrical chamber and having an inletto admit water subject. to impulses in pressure, a plicated metallic bellows arranged within. said casing to partition said chamber into an expansion compartment between said bellows and said casing to receive said. water and a sealed compression compartwater upon its impulses in pressure to limit the .amplitude of its fluctuations in pressure.

'4. A water hammer arrester, comprising in combination, a casing enclosing a cylindrical chamber and having an inlet to admit water subject to impulses in pressure, a plicated metallic bellows arranged within said casing to partition said chamber into an expansion com- 20 partment between said bellows and said casing to receive said water and a sealed compression compartment to contain a compressible fluid to absorb energy from said water and said bellows being composed of annular disks spaced apart from each other and joined together at the inner and outer perimeters thereof in alternation by flanges formed thereon and said disks forming annular pistons fitting close to the walls of said chamber to guide said bellows upon deflection thereof and form constricted passages between said disks and said walls of an order to throttle displacement of water from the external pockets between said pistons to absorb energy from said water upon deflection of said bellows by said impulses in pressure, and a compressible fluid confined within said sealed compression compartment to absorb energy from said water upon its impulsesin pressure to limit the amplitude of its fluctuations in pressure.

EDWIN B.- H. TOWER, JR.

Cancellation of Patent Patent No. 2,273,766, February 17, 1942, Edwin B. H. Tower, J12, WATER HAMMER ARRESTOR.

On October 21, 1949, the District Court of the United States for the Eastern District of Wisconsin rendered judgment by consent in U. S. v. Edwin B. H. Tower, J12, Civil Action N o. 4268, and ordered adjudged and decreed that: United States Letters-Patent No. 2,273,766, issued February 17, 1942, to defendant be and hereby is canceled ab initio. The above udgment has been recorded in the assignment records, liber V221, page 555.

[Ofiicial Gazette December 13, 1.949.]