Abstrict An adapter for a meter chamber provides proportional metering of
a flow through a maincase that is sufficiently accurate at large
flow rates to avoid the unmetered loss of significant quantities
of water. An essentially unobstructed passageway is provided under
the meter chamber to provide a free flow of water through a path
that can be made large enough to avoid flow blockage by debris,
even if the path through the meter becomes blocked. Thus, the adapter
is particularly useful for installation in residential fire service
mains. The adapter includes a chamber housing into which the meter
chamber may be inserted, a bypass plate to hold the meter chamber
in place, and a bypass to provide the passageway through which the
free flow of water flows. The chamber housing includes inlet and
outlet apertures, as does the bypass. The bypass plate separates
a passageway including the meter chamber from the essentially unobstructed
passageway, and the chamber housing is arranged so that essentially
all of the water entering the passageway in which the meter is positioned
flows through the meter chamber. A register on a maincase in which
an adapter containing a positive displacement meter chamber is provided
may be calibrated to accurately register the volume of water flowing
through both chambers of the adapter at significant flow rates.
The adapter thus transforms a positive displacement meter chamber
housed within into a proportional flow meter.
Claims We claim:
1. An adapter for a meter chamber, suitable for use for proportionally
metering a flow of water through a maincase installed in a residential
fire service sprinkler line, the adapter comprising:
(a) means for proportionately dividing an inlet flow of water into
a separate first flow and a separate second flow within a maincase;
(b) means for joining said first flow and said second flow into
an outlet flow within said maincase;
(c) means for engaging a meter chamber within the path of said
first flow so that essentially all of said first flow is directed
through said meter chamber before said first flow is joined with
said second flow into said outlet flow; and
(d) means for passing said second flow essentially unimpeded from
said means for dividing to said means for joining.
2. An adapter for a meter chamber, suitable for use for proportionally
metering a flow of water through a maincase installed in a residential
fire service sprinkler line, the adapter comprising:
(a) a chamber housing dimensioned to receive a meter chamber and
having a first inlet aperture and a first outlet aperture for allowing
a first flow of water to flow through a received meter chamber,
said chamber housing including
(i) a ceiling having an outer perimeter;
(ii) a first outer wall depending from the outer perimeter of said
ceiling and having a bottom rim and an inner surface;
(iii) means disposed within said chamber housing for seating a
meter chamber received therein;
(b) a bypass having a second inlet aperture and a second outlet
aperture for allowing a second flow of water to pass through said
bypass, said bypass including:
(i) a floor;
(ii) a second outer wall extending upward from said floor and dimensioned
for mating engagement with said bottom rim of said first outer wall,
said second outer wall having a top rim and an inner surface; and
(c) a bypass plate for insertion between said chamber housing and
said bypass, for providing fluid isolation between said first flow
of water and said second flow of water.
3. The adapter of claim 2 wherein
(a) said chamber housing further comprises means disposed within
said chamber housing and recessed from said bottom rim of said first
outer wall for supporting said bypass plate in cooperation with
an inner surface of said first outer wall proximate said bottom
rim; and
(b) said bypass further comprises means disposed within said bypass
for supportively engaging said bypass plate within said chamber
housing and said inner surface of said first outer wall proximate
said bottom rim of said first outer wall.
4. The adapter of claim 3 wherein a first gap in said second outer
wall defines said second inlet aperture, and a second gap in said
second outer wall defines said second outlet aperture.
5. The adapter of claim 3 wherein said bypass includes a third
outer wall extending upwardly from said floor, a first gap between
said second outer wall and said third outer wall defining said second
inlet aperture, and a second gap between said second outer wall
and said third outer walls disposed at an offset from a position
diametrically opposite said first gap defining said second outlet
aperture.
6. The adapter of claim 3 wherein said ceiling of said chamber
housing is provided with an aperture to engage a control block extending
from said meter chamber for allowing a drive shaft from said meter
chamber to extend through said aperture.
7. The adapter of claim 3 wherein said bypass is provided with
apertures in said floor to relieve pressure.
8. The adapter of claim 3 wherein said means disposed within said
bypass for supportively engaging said bypass plate within said chamber
housing and said inner surface of said outer wall comprise ribs
disposed on an inner surface of said second outer wall.
9. The adapter of claim 3 wherein said chamber housing includes
means for sealingly engaging an O-ring between said first outlet
aperture and an outlet of a received meter chamber.
10. The adapter of claim 3 wherein said chamber housing includes
means for engaging a screen in said path of flow of water through
said first inlet aperture to prevent debris in a flow of water through
said first inlet aperture from reaching a meter chamber disposed
within said chamber housing.
11. The adapter of claim 3 wherein said bypass plate is provided
with means for compressively engaging a meter chamber within said
chamber housing.
12. The adapter of claim 11 wherein said means for compressive
engagement comprises a raised portion of a surface of said bypass
plate.
13. The adapter of claim 3 wherein said bypass plate and bypass
are unitary, said bypass plate forming a top wall of said bypass.
14. The adapter of claim 3 wherein said chamber housing ceiling
comprises a shoulder for seating against an inner shoulder of a
maincase.
15. The adapter of claim 3 wherein said chamber housing is dimensioned
to receive a 5/8" positive displacement meter, and [the]said
assembled adapter is dimensioned to fit within a 1" maincase.
16. The adapter of claim 3 wherein at least one of said chamber
housing, bypass plate, and bypass are comprised of a plastic material.
17. A method of proportionally metering a volume of water flowing
through a maincase comprising:
(a) seating a positive displacement meter chamber in a first passageway
of an adapter having two passageways, including a second passageway,
said first passageway including means for passing a first flow of
water through said positive displacement meter chamber and said
second passageway for passing a flow of water essentially unimpeded
therethrough;
(b) inserting said adapter including said seated positive displacement
meter into a maincase including a register so that said positive
displacement meter is operatively coupled to said register; and
(c) calibrating said register so that said register records the
amount of water flowing through said maincase.
18. A method of proportionally metering a volume of water flowing
through a maincase comprising:
(a) seating a positive displacement meter chamber in a first passageway
of an adapter having two passageways, including a second passageway,
said first passageway including means for passing a first flow of
water through said positive displacement meter chamber and said
second passageway for passing a flow of water essentially unimpeded
therethrough;
(b) inserting said first adapter including said seated positive
displacement meter into a maincase including a register so that
said positive displacement meter is operatively coupled to said
register, so that all flow through said first passageway passes
through said positive displacement meter; and
calibrating said register proportionally with respect to the flow
of water through said first passageway and said second passageway,
whereby the measurement by said register of the volume of water
passing through said first passageway provides a reading of the
total volume of water passing through said maincase.
Description FIELD OF THE INVENTION
The present invention relates to devices and methods for metering
a flow of water and more particularly to devices and methods for
adapting existing water flow meters for use in metering water in
residential and other fire service sprinkler systems.
BACKGROUND OF THE INVENTION
In 1973 a presidential commission issued a report that suggested
the installation of fire sprinkler systems in all residential buildings
to reduce fire-related deaths. Today, fire marshalls across America
are beginning to require residential sprinkler systems in apartments,
duplex homes, and other buildings to protect both fire and property.
The installation of such systems is particularly important in multiunit
structures, where a fire may begin in one residence and pass quickly
to another due to the adjoining structure. However, in any densely
populated area, a large fire may spread from home to home, and in
sparsely populated areas, the distribution or lack of adequate fire
fighting equipment may increase the hazards and losses should a
fire become started. Thus, residential sprinkler systems are desirable
in all types of residential buildings.
The installation of residential sprinkler systems also saves money.
Many insurance companies offer lower rates for homes having installed
sprinkler systems, particularly for larger homes in those rural
areas that have substandard fire fighting ability. In such cases,
a fire sprinkler system will recover its cost in less than two years.
In cities, city engineers can allow developers to install smaller
fire lines and plugs if fire sprinkler systems are installed in
residential housing, thus lowering the construction cost of the
entire neighborhood.
However, the use of residential lines for fire protection is not
completely devoid of concerns for utility companies. Utility companies
will be held accountable if any utility owned product restricts
water flow to a fire protection sprinkler system. On the other hand,
these same companies are under pressure to meter and bill all water
lines in order to increase revenue and decrease losses caused by
unmetered water. Prior art meters that are used in conventional
ways to meter water are vulnerable to blockages should, for example,
a small stone become lodged in the measuring chamber of the meter.
In such a case, the water flow stops just as though a valve was
shut. As can readily be appreciated, the consequences of such a
blockage in a fire sprinkler system can be serious or even catastrophic.
The NFPA (National Fire Protection Association) promulgates standards
for residential fire lines in NFPA 13R, which is adopted as a regulation
in most areas in the United States. This standard requires residential
fire lines to provide 13 gallons per minute (gpm) to 4 sprinkler
heads, or a total of 52 gpm, which typically is met through the
installation of 1" (one inch) fire lines. Utility companies
presently have two alternatives to prevent the unmetered flow of
water through these fire lines--water flow detectors and 1"
positive displacement meters. Water flow detectors are devices that
alarm the fire department when a flow is detected, which may indicate
either the start of a fire or the use of unmetered water. Their
cost is justified in low volume commercial applications, but the
devices can become costly in high volume residential neighborhoods
and unruly because of false alarms. However, most utility companies
are installing 1" positive displacement meters to record consumption
up to 52 gpm instead of a water flow detector. These meters may
be subject to blockage in critical situations.
It would thus be advantageous to provide a residential fire service
metering device and method that can retrofit existing 1" (and
other size) fire lines, and that avoids flow blockages caused by
debris. Such a metering device and method should also have low head
loss to prevent flow reduction, be able to (at least) register flow
if a home owner taps into a fire line and meter water sufficiently
accurately at high flow rates to avoid giving away large amounts
of free water, and be reasonably priced for large volume residential
applications.
SUMMARY OF THE INVENTION
In accordance with the invention, there is thus provided an assembly
to convert a standard inexpensive positive displacement meter into
a proportional meter, comprising a chamber housing for a preassembled
meter chamber, a bypass plate, and a bypass for mounting within
a maincase. The bypass and bypass plate, in cooperation with one
another, provide an essentially unrestricted flow path for water
to flow through the maincase with little headloss. The chamber housing
and bypass plate cooperate to form a flow path for a portion of
the water entering and leaving the maincase, so that this portion
may be metered by the positive displacement meter. The chamber housing
is provided with a means for screening the inlet flow at the inlet
side of the housing to prevent debris from reaching the inlet of
the meter chamber.
The meter installed in the chamber housing provides proportional
metering of the flow through the maincase that is sufficiently accurate
at large flow rates to avoid the unmetered loss of significant quantities
of water. The essentially unobstructed open space formed between
the bypass and the bypass plate provides a free flow of water through
a path that can be made large enough to avoid flow blockage caused
by debris, even if the path through the meter becomes blocked. Moreover,
inexpensive existing meter chambers designed for smaller maincases
can be used in conjunction with the invention. For example, it is
possible to use identical (or nearly identical) metering devices
in both the 5/8" maincase provided for normal residential service
and the 1" maincase for fire service sprinkler systems, if
the meter chamber in the 1" maincase is installed with the
inventive assembly.
It is thus an object of the invention to provide a device that
can retrofit an existing maincase in a fire line to permit the installation
of a meter to detect and meter the flow of significant quantities
of water, while allowing at least a portion of the flow to a sprinkler
system to be essentially unobstructed.
It is a further object of the invention to provide a device for
allowing the installation of a meter chamber in a maincase with
little resulting head loss, should the flow path through the meter
chamber become blocked.
It is a still further object of the invention to provide a device
to permit the installation of a meter in a maincase so that a substantial
flow of water can be supplied to a sprinkler system without the
risk of flow blockage caused by debris.
It is yet another object of this invention to provide a device
to allow standard, inexpensive meter chambers to be installed in
a fire service line with little or no modification of the meter
chamber, while meeting the standards required for fire protection.
These and other objects of the invention will become readily apparent
to one skilled in the art upon study of the detailed description
that follows .
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an exploded isometric view of a preferred embodiment
of the inventive adaptor, in assembled form, showing its use in
conjunction with a surrounding maincase and an enclosed meter chamber.
FIG. 2 is a partially sectioned elevational view of the inlet and
outlet side of a 5/8" T-10 nutating disk metering chamber preferred
for use in conjunction with the embodiment of the invention illustrated
in FIG. 1.
FIGS. 3A and 3B are top plan and side elevational views, respectively,
of a meter maincase suitable for use in conjunction with the inventive
adapter.
FIG. 4 is an exploded cross sectional view along section line 4
of FIG. 3A of an application of the preferred embodiment of the
inventive adapter, showing its relationship with the various other
components which are used in conjunction with the adapter to provide
proportional flow metering of water for fire service sprinklers,
while providing a substantially unimpeded flow path for a portion
of the water flow.
FIG. 5 is an assembled cut-away cross sectional view of the assembly
shown in exploded form in FIG. 4.
FIG. 6 is a cut-away view of the assembly shown in FIG. 3B along
section line 6 showing the flow of water in the upper chamber of
the adapter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows an exploded isometric view of a preferred embodiment
of the inventive adapter 10 in relation to a maincase and an installed
meter chamber. Adapter 10 comprises a chamber housing 12 a bypass
14 and a bypass plate 16. Bypass plate 16 is sandwiched between
chamber housing 12 and bypass 14 and serves to separate the assembled
adapter 10 horizontally into two independent passageways. The upper
passageway provides a housing for a meter of conventional design.
The lower passageway provides an essentially unobstructed flow of
water, as is required for a fire service sprinkler system.
When adapter 10 is installed in a maincase 80 the water flow generally
follows a path indicated by arrows A and B, which represent flow
from an inlet and to an outlet, respectively. At least one inlet
opening, or more preferably, a pair of inlet openings 18 in the
chamber housing proximate the water inlet indicated by arrow A provide
means to divide the inlet flow of water into a first flow through
the upper one of the two independent passageways. To protect a meter
chamber disposed in the passageway from debris that may be present
in the inlet water flow, filters or screens 20 may be provided to
cover the inlet openings 18 as shown in FIG. 1. Water entering through
inlet openings 18 flows through a meter chamber 70 that may be housed
within the upper passageway, and after flowing through the meter,
flows out through an outlet opening 22 disposed approximately opposite
the inlet openings 18 in a radial direction and provided so that
the outlet flow from the upper passageway can join the outlet flow
from the lower passageway. An auxiliary opening 27 is provided in
the top of chamber housing 12 in a preferred embodiment to allow
a portion of a preferred conventional metering chamber to pass therethrough,
as will be explained later. A small flow of water may pass through
auxiliary opening 27 but the flow eventually fills an upper region
in the maincase above the adapter. The water filling this region
is essentially trapped and stagnant, and does not affect the operation
of a meter chamber used in conjunction with the inventive adapter.
In use, a portion of the inlet water flow is divided into a second
flow by inlet opening 24 in bypass 14. Water entering opening 24
flows essentially unimpeded through the lower passageway in adapter
10 and out through an outlet opening 26 where it merges with the
flow of water exiting from outlet opening 22 to form the outlet
flow generally indicated by arrow B. Means such as tabs 28 on chamber
housing 12 and matching notches 30 on bypass 14 may be provided
to maintain chamber housing 12 and bypass 14 in a fixed relationship
when assembled. Preferably, chamber housing 12 bypass plate 16
and bypass 14 are comprised of plastic, both for ease of fabrication
and to provide some flexibility to allow sealing engagement when
pressure is applied. Other materials may also be used, but may require
the use of gaskets to achieve proper sealing.
The top portion of chamber housing 12 is adapted to seat a conventional
meter chamber and to be compressively engaged within a maincase.
The preferred embodiment has a circular ceiling 32 having auxiliary
opening 27 which, as previously described, provides an opening
for a portion of a meter chamber to pass through. The diameter of
circular ceiling 32 is selected to allow the assembled adapter 10
to fit within the required maincase and to tightly seat a conventional
meter chamber 70 when the adapter 10 is assembled within the maincase
80. The preferred embodiment also has a shoulder 34 for compressional
seating on an internal shoulder of a maincase, as will be described
below.
Hooks or guides 38 are provided for attaching screens for filtering
water entering through inlets 18 because the screening means conventionally
provided with the metering chamber does not function in the larger
enclosure provided by chamber housing 12 except to aid in positioning
the meter chamber in the housing. Means, such as internal walls
36 and 40 together with engagement means, comprising notch 43 and
seating means 42 are provided to engage and position a conventional
metering chamber 70 (An additional seating means is on the opposite
side of outlet 22 and is hidden from view in FIG. 1.). These engaging
and positioning means, which are preferably integrally molded with
chamber housing 12 may differ from those shown here, depending
upon which meter chamber 70 is to be accommodated by the housing
12 and what corresponding means provided on the meter chamber 70
to hold and position it in place. An outlet channel, which, in the
preferred embodiment, includes side walls 45 and bottom wall 44
as well as a portion of shoulder 34 provides fluid communication
between the metering chamber and outlet 22. The chamber housing
12 also comprises an outer wall 46 upon which engagement means 28
are preferably provided. Bottom wall 44 guides 38 and walls 36
40 are recessed somewhat from the rim of an enveloping outside wall
46 to allow a portion of outside wall 46 to form a lip for seating
bypass plate 16.
In the preferred embodiment, bypass 14 comprises an essentially
circular bottom plate 56 having semicircular vertical side walls
50 and 52 around its perimeter. Side walls 50 and 52 are preferably
provided with ribs 54 extending slightly inward from walls 50 and
52. Ribs 54 serve as means for supporting bypass plate 16 which
has slightly smaller diameter than bottom plate 56. It will be understood
that ribs 54 permit bypass plate 16 to form an enclosed lower passageway
with bypass 14 thus providing essentially unobstructed fluid communication
between inlet 24 and outlet 26. It will further be understood that
any other supporting means that allows for such unobstructed fluid
communication may be substituted for ribs 54 within the spirit of
the invention. Although the illustrated inlet and outlet arrangement
is preferred, note that side walls 50 and 52 may also be considered
as a single surrounding wall broken by openings for inlet 24 and
outlet 26 thus suggesting other arrangements for these openings,
such as windows that do not extend the full height of the single
surrounding wall.
At least one, and preferably a plurality of vent holes 55 in bottom
plate 56 are provided in the preferred plastic embodiment to prevent
fatigue caused by fluid pressure from breaking the adapter; water
released through these holes becomes trapped in a "dead"
space between bottom plate 56 and a bottom cap of a maincase in
an actual installation. Notches 30 are preferably provided in side
walls 50 52 to allow bypass 14 to engage the corresponding tabs
28 that are preferably provided in chamber housing 12 to prevent
relative rotation between portions of the assembled adapter 10.
A small projection or tab 53 is provided at one point along the
outer perimeter of bottom plate 56. Referring briefly to FIG. 6
tab 53 mates with a corresponding notch 110 in a post 97 within
a maincase 80 to prevent rotation of the assembled adapter 10 within
maincase 80. Because of the presence of post 97 it is preferred
that the inlet 24 of bypass 14 be offset to avoid being partially
blocked by post 97 when adapter 10 is installed. By being offset
in this way, it is less likely that debris in a flow of water entering
inlet 24 will partially or completely block inlet 24.
Bypass plate 16 in the preferred embodiment is an essentially flat,
circular plate 62 having a preferably integral raised ring 60 for
compressive engagement with a conventional meter chamber. Bypass
plate 16 may also have other means for engaging a preferred meter
chamber, such as a central well 64 having sloping sides dimensioned
to engage the preferred metering chamber.
A preferred metering chamber for 1" maincases is the 5/8"
T-10 Schlumberger nutating disk meter chamber 70 illustrated in
FIG. 2 which shows a view of the adjacent inlet ports 72 and outlet
ports 74 of the meter. The meter chamber is also conventionally
provided with an O-ring 76 for sealing engagement with an outlet.
Outlet 22 of chamber housing 12 (not shown in FIG. 2) is dimensioned
for sealing engagement with O-ring 76 and fluid communication with
outlet ports 74. The assembly comprising the meter chamber and the
inventive adapter, when installed within a maincase, provides a
means for proportionately metering the water flow through the maincase
with minimal head loss, while providing an essentially unobstructed
flow of water that is independent of the metered flow. The particular
meter chamber 70 shown in FIG. 2 is preferred because it can be
readily adapted for proportional use in this application and because
the dimensions of the meter chamber allow a suitably large passageway
to be formed below by bypass plate 16 and bypass 14 in a 1"
maincase for residential fire sprinkler applications.
FIG. 4 shows an exploded view along view line 4 of a complete adapter
provided in a maincase 80 shown in top and side view in FIGS. 3A
and 3B, respectively. The maincase 80 shown in FIG. 4 has a bottom
opening 86 through which a preferred embodiment of adapter 10 and
other associated components are inserted to provide a functioning
proportional flow meter for fire service use. As shown in FIG. 4
circular shoulder 34 of chamber housing 12 rests on an internal
shoulder 84 of maincase 80 as indicated by arrows C. Screen 20
which is preferably stainless steel, fits into the pair of guides
38 so as to provide a filter for inlet port 18. A plastic strainer
81 which is conventionally used in conjunction with the preferred
T-10 meter 70 is seated in notch 43 and serves to compressionally
seat O-ring 76 against outlet port 22. It will, of course, be recognized
that alternate means to sealingly engage the outlet ports 74 of
meter 70 and outlet port 22 of housing 12 may be provided.
Meter chamber 70 in the preferred embodiment rests against the
surface of seating means 42 on ceiling 32 of chamber housing 12
while control block 77 engages opening 27 in the top of housing
12. For the preferred meter chamber 70 this allows drive shaft
78 which is mechanically coupled to a measuring element in meter
chamber 70 to rotate a magnet 79 magnetically coupled to register
82. For the T-10 meter chamber shown, control block 77 and drive
shaft 78 are lengthened somewhat to maintain the standard distance
between the magnet 79 on the drive shaft and a corresponding magnet
(not shown) in register 82. Water use can thus be recorded in a
conventional manner, although register 82 must be specially calibrated
to correctly register proportional flow. Bypass plate 16 which
seats within the outer lip provided by outer wall 46 of chamber
housing 12 closes off the metered upper passageway. The integral
raised ring 60 provides a compression load on the meter chamber
70 and also chamber housing 12 when the entire structure is assembled.
Ribs 54 on walls 50 and 52 (the latter not shown in FIG. 4) on
bypass 14 support bypass plate 16 while notches 30 along the rim
of walls 50 and 52 hold the adapter assembly in alignment. A conventional
gasket 90 and a liner 92 are preferably provided below circular
plate 56 of bypass 14. Gasket 90 assists in sealing and compressing
the assembly within maincase 80 while liner 92 prevents paint on
the bottom cap 94 from contacting water. (Both gasket 90 and liner
92 would also be used if a full-size meter chamber were provided
for maincase 80.) Finally, bottom cap 94 is attached to maincase
80 in a conventional manner using bolts 96 thereby closing and
sealing the opening 86. A cut-away cross-sectional elevational view
of a complete installation is shown in FIG. 5. It will be recognized
that the assembled adapter, with the aid of gasket 90 or other comparable
means, is dimensioned to fill the maincase in such a manner as to
ensure that all water flowing through the maincase will flow through
either the upper passageway defined by chamber housing 12 and bypass
plate 16 or the lower passageway defined by bypass plate 16 and
bypass 14. It will further be understood that the inlet port or
ports of chamber housing 12 (together with any strainer or strainers,
if any) is dimensioned to allow a sufficient fraction of the total
flow of water to flow through a meter chamber enclosed within to
allow at least approximately accurate proportional metering to be
done by the meter chamber, and that the outlet port of chamber housing
12 is dimensional to sealingly engage the outlet port of the meter
chamber to prevent water flowing through the chamber housing from
bypassing the meter chamber. It will additionally be understood
that the inlet and outlet port dimensions of the bypass are to be
sufficiently large to allow a substantial flow of water to pass
unimpeded through the lower passageway of the adapter, and also
large enough to resist clogging by debris that may be present in
the water flow.
The plan cross-sectional view of FIG. 6 (along view line 6 of
FIG. 3B) will aid in understanding the flow of water through the
inventive adaptor 10. Water enters maincase 80 through an inlet
98 as indicated by arrow A. This water enters internal inlet chamber
99 which is in fluid communication with an inlet opening 24 (not
shown in FIG. 6) in the lower portion of adapter 10 and inlets
18 in the upper portion of adapter 10. Water entering inlets 18
a portion of which is indicated by arrows F1 through F4 must flow
in a space around meter chamber 70 to enter meter inlet or inlets
72. Water entering inlet 72 is metered and caused to be registered
by coupling means 79 (on the opposite side of meter chamber 70 in
FIG. 6), which, in a preferred usage, is a rotating magnetic disk
operatively engaged with the metering element, and which is also
magnetically coupled to a register (not shown in FIG. 6). As indicated
by arrow F5 water entering the meter chamber 70 flows out of outlet
22 which is sealingly engaged with outlet or outlets 74 of meter
chamber 70 by means such as an O-ring 76. The inlet flow to and
outlet flow from the meter are kept separated by additional means,
including side walls 45 shown in FIG. 6. In internal outlet chamber
101 the flow of water leaving outlet 22 merges with the flow of
water from outlet 26 from the essentially unobstructed bottom portion
of the adaptor defined by bypass 14 and bypass plate 16 to form
a single flow indicated by arrow F6. This flow exits through the
maincase 80 outlet 100 as indicated by arrow B.
Head loss data was recorded for the preferred embodiment in which
a 5/8" Schlumberger T-10 nutating disk meter is installed in
the adapter, which is, in turn, installed in a standard 1"
maincase. The measured head loss is considerably less with the inventive
adapter when the meter chamber in it is blocked than if a conventionally
installed 1" T-10 meter were used to measure all of the water
flowing through the maincase and the 1" meter became blocked,
as shown in Table I. For comparison purposes, the normal headloss
at 50 GPM for an unlocked 1" T-10 meter is 8 PSI (GPM=gallons
per minute; PSI=pounds per square inch).
To obtain the data in Table I, an adapter having the dimensions
listed in Table II was tested. This embodiment of the adapter, in
conjunction with the meter chamber specified above, causes the meter
chamber to measure about 33% of the water passing through the maincase.
Note that the dimensions of the bypass inlet and outlet openings
are such as to provide openings resistant to clogging by debris
that may exist in the flow of water in the fire service line.
TABLE I ______________________________________ Residential Fire
Service Head Loss 5/8" Meter 1" T-10 Meter in 1"
Maincase in 1" Maincase Chamber locked Chamber locked GPM PSI
GPM PSI ______________________________________ 3 .05 3 9.54 5 .09
5 22.69 8 .28 8 50.37 10 .42 10 73.50 12 .55 12 100.20 15 .83 15
146.30 20 1.47 20 238.30 30 3.06 30 474.00 40 5.24 40 772.10 50
10.1 50 1127.20 ______________________________________
TABLE II __________________________________________________________________________
Inside diameter of chamber housing 4.620 in. Outside diameter of
chamber housing 4.860 in. Total Height of chamber housing, to ceiling
1.706 in. Height of chamber housing, from lip to shoulder 1.356
in. Outlet port of chamber housing 0.920 .times. 0.920 in. at meter
Inlet ports of chamber housing 1.006 .times. 1.750 in. Strainer
2.06 .times. 1.09 in. No. 12 mesh, 0.023 dia. wire Bypass plate
diameters 4.605 in. Bypass plate thickness 0.166 in. Integral Bypass
plate raised ring thickness (above 0.056 in. plate) Bypass diameter
4.860 in. Bypass height 0.860 in. Bypass vertical wall thickness
0.120 in. Ribs 0.124 in. from inside of bypass vertical wall .times.
0.120 in. wide, .times. 10 spaced at aprox. 30.degree. spacings
along walls Bypass inlet opening 0.760 .times. 1.040 in. Bypass
outlet opening 0.760 .times. 1.040 in. __________________________________________________________________________
Register 82 may be calibrated by passing a known volume of water
through maincase 80 and observing, with register 82 the response
of meter chamber 70 to these known volumes. The observed response
will be a response essentially similar to that expected with meter
chamber 70 installed without the inventive adapter 10 in a maincase
of the size for which meter chamber 70 is designed, but proportionately
scaled by a constant which may be determined by experiment for a
particular size maincase, meter chamber, and adapter. This calibration
procedure should be repeated at several flow rates within the specified
range of meter chamber 70 and the observed responses averaged. Steps
can then be taken to calibrate the register, such as providing appropriately
changed gear ratios. It should be noted, however, that the linearity
of the scaling will be poor for weak flows, and thus, weak flows
of water may not be registered correctly and should not be part
of the averaged calibration. For the 5/8" meter chamber tested
in the 1" maincase, calibration rates between 3 and 50 GPM
are satisfactory (Because the meter chamber and adapter tested above
measures about 33% of the water passing through the maincase, the
calibration of the register requires that the register indicate
three times the volume that it would otherwise show for a positive
displacement meter of 5/8" size.). The amount of water lost
by flow rates smaller than those that can be accurately measured
using the inventive adapter will be small, and will be offset by
the capability of the inventive adapter to permit large flows to
be metered with very low head loss and little likelihood of blockage
in the event a flow of water is needed during a fire.
It will be recognized that, once a register is calibrated for a
particular size and type of meter chamber housed within an adapter
of known dimensions for use within a maincase of known dimensions,
the calibration may be used for other registers without repeating
the volume measurement test for each individual meter chamber, adapter,
maincase, and register.
Throughout this description, a specific preferred embodiment has
been described in detail. However, many modifications to this embodiment
will be evident to those skilled in the art within the spirit of
the invention. For example, although the preferred embodiment of
the adapter is designed to accommodate the 5/8" T-10 Schlumberger
nutating disk meter, it will be recognized by one skilled in the
art that other conventional meters with any type of conventional
measuring element may be used, for example, oscillating piston and
multijet (paddle wheel) meters, if the chamber housing, bypass,
and bypass plate are appropriately dimensioned and appropriate seating
means are provided. Moreover, it will also be evident to one skilled
in the art that the invention is not limited to 5/8" meter
assemblies and 1" maincases, but rather may be readily scaled
to meet other size and flow requirements, so long as an adequate
unobstructed flow can be accommodated for the intended purpose in
the lower passageway formed by the bypass plate 16 and bypass 14.
Also, one skilled in the art will readily be able to modify the
various engagement and alignment details that may be necessary to
accommodate other meter housings and to fit into other maincases.
It should additionally be evident to one skilled in the art that
the subassembly comprising bypass plate 16 and bypass 14 could be
provided in alternate configurations that provide an equivalent
subassembly, or even as an integral subassembly, provided that an
essentially unobstructed passageway is provided between ports 24
and 26. Also, the internal details of chamber housing 12 (i.e.,
guides 38 the bottom wall 44 of outlet channel 22 and internal
walls 36 and 40) may be extended up to the rim of enveloping side
wall 46 of chamber housing 12 and ribs 54 recessed from the rims
of walls 50 and 52 of bypass 14 by the thickness of bypass plate
16 thereby allowing bypass plate 16 to seat within a lip formed
by walls 50 and 52 of bypass 14 rather than within enveloping side
wall 46 of chamber housing 12.
This list of possible modifications is not intended to be exhaustive,
and many other modifications will be readily apparent to one skilled
in the art. Thus, the scope of the invention should be determined
by reference to the claims below rather than to the specific details
of the embodiment described herein. |