Water hammer absorber

A water hammer absorber provided in a cold or hot water supply passage including: a tubular portion whose cross section gradually decreases toward a flow direction of cold or hot water until the inner diameter of the portion becomes minimum and then gradually increases toward that direction so that a negative pressure generates therein; and a pressure absorbing chamber which is formed at the minimum inner diametered section of the tubular portion or therearound at the downstream side so as to communicate with the water supply passage and which is provided with a passage-way leading to the atmosphere and a check valve disposed in the passage-way and capable of admitting the entry of air only into the pressure absorbing chamber. The absorber according to the invention is suitably used in the joint of a delivery faucet or a mixing faucet.

FIELD OF THE INVENTION AND RELATED ART STATEMENT 
The present invention relates to a novel water hammer absorber that absorbs 
water hammer produced in a cold or hot water supply pipe or the like to 
protect the supply pipe itself and a faucet appliance connected to the 
pipe for delivering water or stopping water flow. 
FIG. 3 is a side elevation in cross section of a conventional water hammer 
absorber. The absorber, generally indicated by numeral 3, is mounted in a 
pipe 1 that supplies cold or hot water to a delivery faucet mounted above 
a washstand or sink (not shown). The absorber 3 consists of a spherical 
casing 4 and a joint pipe 2. The inside of the casing 4 is partitioned 
into a pressurization chamber 4a and a compression chamber 4b by a 
diaphragm 4c. Generally, the compression chamber 4b is sealed with 
nitrogen gas. The pressure inside the chamber 4b is kept at about 4 
Kg/cm.sup.2 If nitrogen gas should leak, it would not be dangerous to the 
human body. For these reasons, nitrogen gas is used. The pressurization 
chamber 4a is in communication with the supply pipe 1 through the joint 
pipe 2. When a faucet appliance (not shown) connected to the supply pipe 1 
is quickly operated to stop water flow, the pressure inside the pipe 1 
rises excessively, thus producing a shock wave. Then, the wave is 
transmitted through the pipe 1. The water inside the pressurization 
chamber 4a of the absorber 3 curves the diaphragm 4c toward the 
compression chamber 4b. Therefore, no reflecting wave is produced in 
response to the shock wave. Consequently, the water hammering disappears. 
The volume of the conventional water hammer absorber 3 is large , because 
it has the pressurization chamber 4a filled with water and the compression 
chamber 4b having a content volume large enough to permit deformation of 
the diaphragm 4c. Therefore, it is impossible to later attach the absorber 
3 to the water supply pipe 1 which is mounted in the rear of a wall or the 
like. The possibility was contemplated that the water hammer absorber 3 
was mounted to the joint with a delivery faucet or mixing faucet (not 
shown) at which the supply pipe 1 protruded from a building wall. However, 
this was hardly realized, because it was quite inferior from an 
aesthetical point of view. Further, the conventional water hammer absorber 
3 has the following disadvantages. The diaphragm 4c is made from nitrile 
rubber or the like, and also acts as packing for preventing leakage of gas 
from the compression chamber 4b. However, it is unable to provide perfect 
seal. Further, the nitrile rubber itself transmits a trace of nitrogen 
gas. Therefore, the water hammer absorber ceases to function 
satisfactorily in a relatively short term of about six months to one year. 
Whenever the performance drops, the absorber is recharged with gas, or the 
absorber 3 itself is replaced with a new one. Hence, the running cost is 
high. Furthermore, the recharging operation and the replacing operation 
are quite cumbersome to perform, because the absorber 3 is usually mounted 
in the depths of a building, in a pipe extending through a wall, or in a 
pipe mounted in a compartment formed below a sink or washstand. 
OBJECTS AND SUMMARY OF THE INVENTION 
In view of the foregoing circumstances, the present invention has been 
made. It is an object of the invention to provide a water hammer absorber 
which makes it unnecessary to recharge the absorber with nitrogen gas or 
to replace the absorber itself and which can save the running cost. 
It is another object of the invention to provide a novel water hammer 
absorber which is adapted for use with a mixing faucet and can be mounted 
to the joint between a cold or hot water supply pipe protruding from a 
building wall and a mixing faucet or the like. 
It is a further object of the invention to provide a water hammer absorber 
which is adapted for use with a washstand. 
According to the invention there is provided a water hammer absorber 
comprising a tubular portion and a pressure-absorbing chamber. The tubular 
portion is provided in a water supply passage and the cross section 
thereof gradually decreases toward a flow direction of cold or hot water 
flows until the inner diameter thereof becomes minimum and then gradually 
increases in the flow direction of the cold or hot water so that a 
negative pressure generates therein by the passage of the cold or hot 
water therethrough. Further, the pressure absorbing chamber is formed in 
the water supply tube and at the minimum inner diametered section of the 
tubular portion or therearound at the downstream side and provided with a 
passage communicating the atmosphere and a check valve disposed in the 
passage and capable of admitting the entry of air only in the 
pressure-absorbing chamber. 
According to the invention there is also provided a water hammer absorber 
comprising an inner choke tube and a body portion. The choke tube has a 
narrowed portion which is disposed in a water supply passage for supplying 
cold or hot water. The body portion is disposed above the choke tube and 
having a pressure-absorbing chamber that is in communication with the 
narrowed portion through a water injection passage. A valve seat is formed 
inside the chamber and around the entrance of the chamber from which the 
water injection passage extends. A float valve is disposed inside the 
chamber opposite to the valve seat. A short tapering pipe is mounted in 
the narrowed portion. All the water flowing into the choke tube passes 
through the tapering pipe. A negative pressure is produced by the flow of 
water through the tapering pipe. Preferably, a gap is formed between the 
inner surface of the narrowed portion and the tapering pipe to transmit 
the negative pressure to the water injection passage through the narrowed 
portion. 
It is now assumed that a shock wave is produced by a violent rise in the 
pressure inside the water supply pipe. When water flows through the inner 
choke tube mounted in the water supply pipe, the inside of the 
pressure-absorbing chamber in the body portion is filled with air. The 
shock wave reaching the choke tube flows into the chamber through the 
water injection passage as flow of cold or hot water. Therefore, the shock 
wave is absorbed, and no reflecting wave is generated. The water hammer 
disappears. 
When water flows through the inner choke tube, the inside of the 
pressure-absorbing chamber is filled with air, because the chamber is in 
communication with the narrowed portion of the choke tube. In particular, 
when cold or hot water flows through the water supply pipe, a differential 
pressure is created between the supply pipe and the narrowed portion of 
the choke tube. Of course, the pressure inside the narrowed portion 
becomes lower than the pressure inside the supply pipe, thus producing a 
negative pressure This negative pressure prevents hot or cold water from 
flowing into the chamber. Therefore, the chamber is always ready to absorb 
a shock wave caused by a violent rise in the pressure. The float valve 
disposed in the chamber acts to prevent an excessive amount of air from 
being drawn from the chamber when the pressure inside the narrowed portion 
of the choke tube is negative. When a shock wave forces cold or hot water 
into the chamber, the valve floats so as not to impede the inflow of the 
water. 
According to the invention there is further provided a water hammer 
absorber mounted in a pipe connected with a delivery faucet installed over 
a washstand, sink, or the like. The absorber includes an intake coupling 
and a discharge coupling connected with water supply pipes and a water 
stop cock. The absorber further includes a water channel interconnecting 
the couplings and having a narrowed portion. A pressure-absorbing chamber 
is formed around the narrowed portion and in communication with the 
narrowed portion via one or more water injection holes. 
According to the invention there is yet provided a water hammer absorber 
mounted in a mixing faucet, the absorber comprising an intake coupling 
connected with a cold or hot water supply pipe mounted in a building wall 
or the like, a discharge coupling connected with the body of the faucet, a 
water channel interconnecting the couplings and having a narrowed portion, 
and a pressure-absorbing chamber formed around the narrowed portion and 
placed in communication with the narrowed portion via one or more water 
injection holes. 
We now assume that the mixing faucet or the delivery faucet installed over 
a washstand or the like is quickly operated to stop the flow of water and 
that a shock wave is produced in the pipe connected with the faucet, such 
as a water supply pipe, by a violent rise in the pressure. When water 
flows through the water supply pipe, the inside of the pressure-absorbing 
chamber is filled with air or contains a mass of air. Thus, the shock wave 
reaching the narrowed portion flows into the chamber through the water 
injection passage as flow of water. Since the shock wave compresses the 
air, it is absorbed, and no reflecting wave is produced. Consequently, the 
water hammer disappears. 
As can be understood from the description made thus far, a special gas such 
as nitrogen gas is not stored in the novel water hammer absorber and so 
there is no possibility of leakage of gas. Therefore, neither recharging 
of the absorber with gas nor replacement of the absorber itself is 
required. Also, there exist no mechanical moving parts except for 
attachments for the check valve. For this reason, the possibility of 
trouble is almost eliminated. In other words, the absorber can be used 
almost permanently at no running cost. 
In the conventional water hammer absorber, the nitrogen gas filling the 
compression chamber is compressed to secure space allowing inflow of cold 
or hot water, thus absorbing a shock wave. In this structure, the 
diaphragm that absorbs a shock wave is required to have a large area. 
Further, a sufficient volume of nitrogen must be compressed inside the 
compression chamber. Consequently, the conventional absorber is made 
considerably large in size. In contrast with this, in the novel absorber, 
the air inside the pressure-absorbing chamber is mixed with cold or hot 
water to absorb a shock wave. Therefore, the space inside the chamber 
which is used to absorb a shock wave can be effectively utilized. Further, 
larger pressures can be absorbed, since a shock wave is converted into 
flow of cold or hot water into the chamber. Even with a supply pipe to 
which plural delivery faucets are connected in such a manner that the pipe 
branches off, it is not necessary to mount the novel absorber to every 
delivery faucet; it suffices to mount the single absorber to the main pipe 
at a location where it does not yet branch off. In other words, the novel 
absorber mounted to a single delivery faucet can be rendered quite small. 
In this way, the novel absorber yields various excellent advantages. 
The appearance of the novel absorber can be hardly distinguished from a leg 
normally mounted to a mixing faucet, by connecting the intake coupling 
with a cold or hot water supply pipe mounted in a building wall or the 
like and connecting the discharge coupling with the body of the mixing 
faucet. Accordingly, one who sees this absorber would not feel strange. 
The absorber can also be mounted to a mixing faucet already installed. If 
necessary, it can be mounted to only a cold water supply pipe or a hot 
water supply pipe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIGS. 9 and 10 show preferred embodiments of the present invention wherein 
there is provided a water tube 64 forming itself a supply passage in a 
casing 63 provided with a cold or hot water inlet port 61 and an outlet 
port 62. Both ends of the tube 64 are fitted in portions 65 and 66 having 
circular inner peripheral surfaces and provided adjacent the ports 61 and 
62, respectively. The tube 64 is in the form of a venturi and includes a 
portion 67 whose inner diameter gradually decreases toward a direction G 
of the flow of water, a minimum inner diametered section 68 and a portion 
69 whose inner diameter gradually increases. The outer periphery of the 
tube 64 of the casing 63 defines a pressure-absorbing chamber 70 which is 
in communication with the tube 64 through an opening 71 provided at a 
portion slightly spaced toward the downstream side from the minimum 
diametered section 68. In the the casing 63 there is provided is a check 
valve 72 covered with a ventilating dustproof cap and which operates such 
that it admits only the entry of the air into the pressure-absorbing 
chamber 70 and checks the outflow of a fluid from the casing 63. 
Next, the operation of the absorber according to the present invention will 
be described. The absorber is mounted in such a manner that water flows 
along the direction G designated by the arrow. When no water flows through 
the tube 64 of the absorber, the pressure-absorbing chamber 70 is almost 
full of water. Assuming that water be made to flow through the tube 64 by 
operating a faucet appliance (not shown) on the downstream side of the 
absorber. Then the inner pressure of the minimum inner diametered section 
or therearound on the downstream side becomes negative Accordingly, the 
water filling the pressure absorbing chamber 70 tends to be sucked into 
the tube 64 through the opening 71 and at the same time, the open air is 
sucked into the pressure absorbing-chamber 70 through the check valve 72 
so that the chamber 70 is filled with the air. 
Now, assuming that a shock wave be transmitted to the flow of the water due 
to an abrupt pressure rise in a direction reverse to the water flow by 
suddenly operating the faucet appliance to stop the water, the shock wave 
would enter the pressure-absorbing chamber 70 through the opening 71 as a 
flow of the water. Accordingly, the energy of the shock wave would be 
absorbed without the generation of a reflecting wave resulting therefrom 
so that no water hammer phenomenon takes place. Then, when the faucet 
appliance is opened, water flows through the tube 64 again so that the 
pressure absorbing chamber is filled with air so as to become ready for 
the absorption of a next shock wave. 
The absorber shown in FIGS. 11 and 12 is so mounted as cold or hot water 
flows upward and in this attitude the check valve 72 is arranged at a 
portion above the pressure-absorbing chamber 70. As the remaining 
structure is the same as that shown in FIGS. 9 and 10, like portions or 
members are designated by the same reference numerals 
Further, in FIGS. 10 and 12, the opening 71 may be provided at the minimum 
diametered section 68. 
Referring to FIGS. 1 and 2, there is shown a water hammer absorber 
embodying the concept of the present invention. The body of the absorber 
is generally indicated by numeral 6. The absorber includes an inner choke 
tube 5 that is mounted inside a supply pipe 1 for supplying cold or hot 
water. The choke tube 5 has couplings 5a at its both ends to permit the 
tube 5 to be connected to the supply pipe 1. The tube 5 has a narrow 
portion 5c in its center. The inside diameter of the tube decreases 
gradually from the couplings 5a at both ends of the tube 5 to the narrow 
portion 5c. The inside diameter of the narrow portion 5c is about half of 
the inside diameter of the supply pipe 1. A branch tube 5b extends 
upwardly from the narrow portion 5c, and is internally threaded to form a 
coupling for connection with the body 6. 
The body 6 takes the form of a long cylinder, and can be divided into an 
upper cylindrical portion 6a and a lower cylindrical portion 6b. The 
inside of the upper portion 6a is hollow. When the upper portion 6a is 
coupled to the lower portion 6b, a pressure-absorbing chamber 7 is formed. 
The lower portion 6b has an externally threaded end portion 6c, which 
extends downward and is screwed into the branch tube 5b of the inner choke 
tube 5. The end portion 6c is provided with a water supply passage 7a. A 
conic valve seat 7b is formed around the opening in the passage 7a which 
is located on the side of the pressure-absorbing chamber 7. 
A spherical float valve 9 is mounted in the pressure-absorbing chamber 7 
that is formed when the upper tubular portion 6a and the lower tubular 
portion 6b are coupled together. The valve 9 is made of a synthetic resin 
or other similar material and floats on water. When the externally 
threaded end portion 6c of the body 6 is engaged in the branch tube 5b of 
the inner choke tube 5, a space is left below the end portion 6c inside 
the body 6. The diameter of this space is considerably larger than the 
inside diameter of the narrow portion 5c of the choke tube 5 and so the 
space substantially increases the inside diameter of the narrow portion 
5c. If this space was left as it was, then negative pressure would be 
reduced by this space. In this example, therefore, a tapering i short pipe 
8 is inserted in the coupling 5a at one end of the choke tube 5. The thick 
of the short pipe 8 is fitted in the end of the choke tube 5 at which 
water enters. All the water flowing into the choke tube 5 passes through 
the pipe 8, which is long enough to extend across the narrowest section of 
the narrow portion 5c. The choke tube 5 has a drain portion 5f into which 
water flows through the narrowest end of the short pipe 8. When water 
enters the drain portion 5f from the short pipe 8, a negative pressure is 
produced in the drain portion 5f. The negative pressure is transmitted to 
the water supply passage 7a through a clearance formed between the outer 
surface of the pipe 8 and the inner surface of the narrow portion 5c. 
The absorber is so mounted that cold or hot water flows in the direction 
indicated by the arrow A. When no water flows through the supply pipe 1 as 
shown in FIG. 2, cold or hot water which flowed into the 
pressure-absorbing chamber 7 in the body 6 from the drain portion 5f in 
the supply pipe 1 as indicated by the arrow B stays in the chamber 7. When 
cold or hot water is forced through the supply pipe 1 using a faucet 
appliance (not shown) connected with the pipe 1, a pressure difference is 
created between the coupling 5a on the exit side and the narrow portion 
5c, thus producing a negative pressure inside the narrow portion 5c. Then, 
the cold or hot water which first flowed into the pressure-absorbing 
chamber 7 in the body 6 is drawn and expelled. As a result, the float 
valve 9 closes off the water supply passage 7a as shown in FIG. 1. 
Under this condition, if the faucet appliance (not shown) is quickly 
operated to stop the flow of water, then the pressure inside the supply 
pipe 1 rises violently, producing a shock wave. The shock wave raises the 
float valve 9 that closes off the passage 7a, and enters the 
pressure-absorbing chamber 7 as flow of hot or cold water. Therefore, the 
energy of the shock wave is absorbed. No reflecting wave is produced in 
response to the shock wave. Consequently, the water hammering disappears. 
If the faucet appliance (not shown) is subsequently used, then hot or cold 
water flows through the supply pipe 1, and cold or hot water is drawn out 
of the pressure-absorbing chamber 7 in the body 6. Hence, the absorber is 
momentarily reset. 
When water is drawn from the chamber 7 and expelled, there arises the 
possibility that even air needed for the chamber 7 is drawn into the 
supply pipe 1. In the present example, therefore, a check valve 10 is 
mounted in the upper cylindrical portion 6a in the body 6 to inhale air. 
As soon as water is drawn out of the chamber 7, the check valve 10 takes 
in substantially the same amount of outside air to promote discharge of 
the water. 
It is to be noted that neither the aforementioned tapering short pipe 8 nor 
the check valve 10 is essential to the invention. The body 6 can also be 
shaped in the form of a square pole or disk. The absorber can be mounted 
anywhere in the connected pipe, including a position located immediately 
before the faucet appliance. Further, it may be incorporated in a faucet 
appliance, such as a delivery pipe, instantaneous water heater, or 
water-heating appliance. In this way, the structure and the shape of the 
novel absorber may be varied according to practical situations. 
Referring next to FIG. 4, there is shown a washbowl 15 equipped with 
another water hammer absorber according to the invention. A delivery 
faucet 16 is mounted above the washbowl 15 and receives hot or cold water 
from piping that includes a supply pipe 17 and a water stop cock 18. The 
absorber is mounted in a pipe that connects the pipe 17 with the cock 18. 
The absorber is particularly shown in FIG. 5, and has an intake coupling 21 
at its lower end for connection with the water stop cock 18. The absorber 
includes a discharge coupling 20 at its upper end for connection with the 
supply pipe 17. The inside diameter of the passage formed between the 
couplings 20 and 21 is gradually changed such that it is narrowest about 
its center. The narrowest portion, indicated by numeral 22, is provided 
with one or more water injection holes 23 extending laterally through it. 
In this specific example, the tapering portions located on opposite sides 
of the narrowest portion 22 are formed integrally out of an anticorrosion 
metal, such as stainless steel, brass, or bronze, or other material , such 
as rubber or synthetic 
A pressure-absorbing chamber 24 is formed around the narrowest portion 22 
and extends laterally to form a boxlike portion. A check valve 25 used for 
air suction alone is mounted on the boxlike portion. A dustproof cap 26 is 
mounted over the check valve 25. Preferably, the valve 25 is so mounted 
that it moves vertically. Where the absorber is mounted in a horizontal 
pipe such as the joint between the water stop cock 18 and the water supply 
pipe 19, the check valve 25 may be mounted as shown in FIG. 6. 
The operation of the absorber is now described by referring to FIG. 5. The 
absorber is so mounted that water flows in the direction indicated by the 
arrow C. When no water flows through the narrowest portion 22, the 
pressure-absorbing chamber 24 is substantially filled with water. It is 
now assumed that the delivery faucet 16 (see FIG. 4) located above the 
washbowl 15 is opened to permit water to flow through the narrowest 
portion 22. At this time, the pressure inside the narrowest portion 22 
becomes lower than the pressure inside the supply pipe 19, creating a 
negative pressure. Then, the water contained in the pressure-absorbing 
chamber 24 is drawn into the supply pipe 19 through the water injection 
holes 23 in the narrowest portion 22. Simultaneously, outside air is drawn 
into the chamber 24 via the check valve 25. Thus, the chamber 24 is filled 
with air. 
We now assume that the delivery faucet 16 is quickly closed and that a 
shock wave due to a violent rise in the pressure is transmitted through 
the supply pipe 17 in a reverse direction. The shock wave enters the 
pressure-absorbing chamber 24 from the water injection holes 23 as flow of 
water. The energy of the shock wave is absorbed and so no reflecting wave 
is produced in response to the shock wave. In this manner, the water 
hammering disappears. If the delivery faucet 16 is subsequently opened, 
water again flows through the narrowest portion 22. Then, the 
pressure-absorbing chamber 24 is again filled with air. Thus, preparations 
are made for absorption of the next shock wave. 
The position at which the absorber is mounted is not limited to a location 
(FIG. 5) lying between the supply pipe 17 and the water stop cock 18 or to 
a location (FIG. 6) situated between the water stop cock 18 and the water 
supply pipe 19. The absorber may be installed between the supply pipe 17 
and the delivery faucet 16 in a manner not illustrated. Sometimes, the 
water supply pipe 19 extending upright from a floor is directly connected 
to the delivery faucet 16 disposed above the washbowl 15. In this case, 
the absorber may be mounted in the supply pipe 19 or between the pipe 19 
and the delivery faucet 16. The pressure-absorbing chamber 24 may be 
shaped like an independent can and connected from outside of the narrowest 
portion 22. Of course, the location of the narrowest portion 22 formed in 
the passage in the absorber, the number of the water injection holes 23 
formed in the narrowest portion 22, the diameter of the holes, the 
positions of the holes, and other factors may be modified according to the 
pressure of the supplied water and other considerations. 
Referring to FIG. 7, there is shown a mixing faucet 35 which has a water 
hammer absorber 30 mounted in a cold water supply pipe and another water 
hammer absorber 31 mounted in a hot water supply pipe. The body of the 
faucet 35 is indicated by numeral 36. The faucet 35 includes a delivery 
pipe 37 and a lever 38 for controlling the amount of delivery and the 
temperature of the delivered water. 
The absorber 30 shown in FIG. 8 is shown in FIG. 7 in cross section. This 
absorber takes the form of a rectangular box and is tilted. An inclined 
L-shaped channel which begins with a lower entrance 41a and ends with an 
upper exit 40a is formed inside the absorber. The entrance 41a extends 
downwardly as viewed in the figure to form an intake coupling 41 for 
connection with a water supply pipe (not shown) as shown in FIG. 7. The 
exit 40a extends upwardly as viewed in FIG. 8 to form a discharge coupling 
40 for connection with the body 36 of the faucet as shown in FIG. 7. The 
channel formed between the couplings 40 and 41 is designed so that the 
lower end of the web is narrowest and that the inside diameter of the 
channel gradually increases from the narrowest portion 42 toward both 
ends. The narrowest portion 42 is formed with one or more water injection 
holes 43 extending laterally through it. In this specific example, both 
sides of the narrowest portion 42 are formed integrally out of an 
anticorrosion material, such as stainless steel, bronze, or brass, or 
other material, such as rubber or synthetic resin. A water stop cock 47 
(FIG. 7) is mounted to the entrance 41a to control the flow rate or stop 
the flow during maintenance. 
A pressure-absorbing chamber 44 is formed around the narrowest portion 42 
and swells obliquely upwardly to form a boxlike portion. A check valve 45 
used for air suction alone is mounted on the boxlike portion. A dustproof 
cap 46 is disposed over the check valve 45. 
The operation of the absorber is now described by referring to FIG. 8. The 
absorber is so mounted that water flows in the direction indicated by the 
arrows D and E. When no water flows through the narrowest portion 42, the 
pressure-absorbing chamber 44 is substantially filled with water. It is 
now assumed that the lever 38 of the mixing faucet 35 (FIG. 7) is operated 
to open the passage and that water flows through the narrowest portion 42. 
Under this condition, the pressure inside the narrowest portion 42 becomes 
lower than the pressure inside the water supply pipe, creating a negative 
pressure. Thus, the water contained in the pressure-absorbing chamber 44 
is drawn into the exit 40a through the water injection holes 43 in the 
narrowest portion 42. At the same time, outside air is drawn into the 
pressure-absorbing chamber 44 through the check valve 45. Thus the chamber 
44 is filled with air. 
If the lever 38 is quickly operated to stop the flow of water, then the 
pressure inside the body of the faucet 36 rises violently to produce a 
shock wave traveling in a reverse direction. The shock wave enters the 
pressure-absorbing chamber 44 via the water injection holes 43 as flow of 
water. Therefore, the energy of the shock wave is absorbed, and no 
reflecting wave is produced. Hence, the water hammer disappears. If the 
lever 38 is subsequently operated to open the faucet, then water again 
flows through the narrowest portion 42. The inside of the 
pressure-absorbing chamber 44 is again filled with air. Thus, preparations 
are made for absorption of the next shock wave. 
The location of the narrowest portion 42 in the passage, the number of the 
water injection holes 43 formed in the narrowest portion 42, the diameter 
of the holes, the location of the holes, and other factors may be modified 
according to the pressure at which hot or cold water is supplied. In this 
way, the structure and the shape of the novel absorber can be varied 
according to practical circumstances.