U.S. patent application number 10/142206 was filed with the patent office on 2003-11-13 for pump pressure limiting engine speed control.
Invention is credited to Whitney, John.
Application Number | 20030210984 10/142206 |
Document ID | / |
Family ID | 29399829 |
Filed Date | 2003-11-13 |
United States Patent
Application |
20030210984 |
Kind Code |
A1 |
Whitney, John |
November 13, 2003 |
Pump pressure limiting engine speed control
Abstract
A sprinkler system for a building includes an internal
combustion engine which operates a water pump. The water pump in
turn forces water through pipes to sprinkler heads. The engine is
at least in part controlled by a throttle control mechanism which
includes a spring biased piston which is moved in response to the
output pressure of the pump. This prevents the pump from exceeding
the rated capacity of the system components.
Inventors: |
Whitney, John; (Blanchester,
OH) |
Correspondence
Address: |
WOOD, HERRON & EVANS, LLP
2700 CAREW TOWER
441 VINE STREET
CINCINNATI
OH
45202
US
|
Family ID: |
29399829 |
Appl. No.: |
10/142206 |
Filed: |
May 9, 2002 |
Current U.S.
Class: |
417/34 |
Current CPC
Class: |
F04D 15/0066 20130101;
F04D 15/0209 20130101 |
Class at
Publication: |
417/34 |
International
Class: |
F04B 049/00 |
Claims
This has been a description of the present invention and the
preferred mode of practicing the invention, however, the invention
itself should only be defined by the appended claims wherein we
claim:
1. A building sprinkler system having a pump said pump activated by
an internal combustion engine; said engine having a throttle; said
throttle attached to a control said control responsive to the
output pressure of said pump and adapted to reduce engine speed at
a pre-determined pressure.
2. The building sprinkler system claimed in claim 1 wherein said
control has a piston said piston is linked to said throttle wherein
said piston moves in response to said output pressure.
3. The sprinkler system claimed in claim 2 wherein said piston is
spring biased.
4. The sprinkler system claimed in claim 3 wherein said piston
rides in a cylinder having an end wall; and a spring located
between said end wall and said piston urging said piston away from
said end wall.
5. The sprinkler system claimed in claim 4 wherein said cylinder
includes an end cap and wherein further comprising at least one
shim between said cap and said spring.
6. The sprinkler system claimed in claim 2 wherein said piston
includes a first cylindrical portion which rides in a cylindrical
chamber wherein water from said pump is directed to said chamber
and being effective to move said piston at said predetermined
pressure.
7. The sprinkler system claim in claim 6 wherein said piston has a
stop member wider than said cylindrical chamber.
8. A sprinkler system having a series of components said components
having a rated pressure capacity; a pump connected to an internal
combustion engine and having pressure capability which when
combined with a system suction pressure exceeds said rated pressure
of said components; throttle control responsive to water pressure
from said pump adapted to prevent said water pressure from said
pump from exceeding the rated pressure of said components.
9. The sprinkler system claimed in claim 5 wherein said piston
further rides in a cylindrical chamber having an end portion
wherein said piston extends beyond said end portion and has a stop
member having diameter greater than the diameter of said
cylindrical chamber.
Description
BACKGROUND
[0001] Building sprinkler systems are designed to provide water to
extinguish fires during emergency situations. Typically a pump is
used to provide the necessary water pressure. These pumps can be
powered by internal combustion engines.
[0002] The sprinkler systems themselves are designed to operate
within a defined flow rate and pressure. The pumps must be able to
generate the defined flow rate. For a given pump, the pressure is
dependent on flow rate. At a fixed speed, as the flow rate
decreases, the pressure tends to increase. Further as flow rates
decrease, the load on the engine decreases and the rpm increases
thereby further increasing pressure produced by the pump (this is
referred to as the engine droop). The net effect is to increase the
pressure which a sprinkler system must be able to handle. This
basically means stronger more expensive sprinkler system components
including water pipes, fittings and sprinklers. Sprinklers are
rated for specific operating pressures. This establishes the limits
of the system pressures. Some types of sprinkler are further
limited to smaller more specific pressure ranges further limiting
system pressure ranges. The pressure of the water at the pump
suction (called suction pressure) often has a wide range between
its high and low resulting in equally wide contribution to pump
output pressure variances.
SUMMARY OF THE INVENTION
[0003] The present invention is premised on the realization that
the need for higher pressure rated sprinkler systems can be avoided
by utilizing an engine throttle control which is responsive to the
output pressure of a pump. As the pump pressure increases above a
defined pressure, a control mechanism is utilized to pull back the
throttle reducing engine rpm and in turn maintaining a constant
pressure.
[0004] Preferably the control mechanism is a piston which is
attached to the throttle and forced in a direction that pulls the
throttle back when water pressure is increased. Preferably the
piston is spring biased so that when the pressure decreases, the
throttle will return to its normal setting to operate the pump
within design parameters. Knowing the pressure at the rated flow of
the pump allows one to adjust the control mechanism to maintain
this pressure even at low flow rates thereby eliminating the need
for the more expensive plumbing created by undesirable
pressure.
[0005] The objects and advantages of the present invention will be
further appreciated in light of the following detailed description
and drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0006] FIG. 1 is a perspective view of the present invention.
[0007] FIG. 2 is a cross-sectional view of the throttle control of
the present invention.
[0008] FIG. 3 is a cross-sectional view of the throttle control
shown in a different position according to the present
invention.
DETAILED DESCRIPTION
[0009] As shown in FIG. 1, sprinkler system 12 includes a pump 14
which directs water from an inlet pipe 18 and through outlet pipe
16 to sprinkler heads (not shown). The pump 14 is in turn operated
by an internal combustion engine 22 as shown in FIG. 1, preferably
a diesel engine. Engine 22 drives the shaft 24 which in turn
operates the pump 14.
[0010] The rpm of engine 22 and thereby the shaft 24 is controlled
by a throttle 26. This is operatively connected to a control
mechanism 28 which is mounted on the engine 22 by bracket 32.
[0011] As shown more particularly in FIGS. 2 and 3, the control
mechanism 28 includes a piston 34 which extends through a block 36.
Rearwardly of block 36 is a cylindrical casing 38 which screws onto
block 36. Opposite block 36 is a cap 42 which screws onto the
cylindrical casing 38 holding it in position. Between the cap 42
and the piston 34 is a spring 44 which engages a rear end 46 of
piston 34.
[0012] Piston 34 includes a shaft 48 having a threaded end 52. The
opposite end of piston 34 terminates with a stop member 56 which in
turn is larger than the piston 34.
[0013] The piston 34 rides in block 36 which includes an enlarged
axial first cylindrical chamber 58 and a smaller aligned second
cylindrical chamber 62. First and second O-rings 64 and 66 are
seated axially in chambers 58 and 62 respectively. Piston 34 is
located in the first cylindrical chamber 58 and a seal is formed
between piston 34 and the wall of chamber 58 by o-ring 64. The
shaft 48 of piston 34 extends through the smaller second chamber 62
and again forms a seal with o-ring 66. The stop member 56 of piston
34 is larger than the large axial chamber 58 and acts as a stop
limiting the movement of piston 34 relative to block 36.
[0014] Block 36 further includes first and second threaded
transverse openings, 68 and 72 respectively which lead to chamber
58. The first threaded opening 68 is sealed by a bleed valve 74.
The second threaded opening 72 is connected to tube 76 which
extends to pipe 16 which is downstream of pump 14. Tube 76 further
includes a strainer 78.
[0015] The threaded end 52 of piston 34 attaches via turnbuckle 82
to throttle control linkage 84 which in turn is attached to the
throttle 26.
[0016] In operation when the engine 22 is activated, it will cause
pump 14 to rotate increasing the water pressure in pipe 16. Tubing
76 and chamber 58 of block 36. The water pressure (when it reaches
a defined level) within block 36 will force the piston 34 to move
in the direction of arrow 88 pulling the throttle back decreasing
the rpm's for the engine and the output pressure from the pump.
When the pressure is reduced below a defined pressure, the spring
44 will force the piston 34 back toward its starting position as
shown in FIG. 2. The stop member 56 will engage a rear end of block
36 preventing further movement. When stop member 56 engages block
36, the throttle 26 is positioned for the engine to provide its
rated power to drive pump 14.
[0017] The present invention includes two mechanisms to adjust the
operation of the control unit 28. Between cap 42 and spring 44 are
one or more metal disks or shims 92 which will increase the
pressure applied by the spring against the piston 34. By
calculating the effect of a shim, one can determine the number of
shims needed to achieve the necessary operating pressures.
Alternatively, a bolt 94 could be threaded through cap 42 to adjust
the pressure on spring 44 as best shown in FIG. 3. Further,
turnbuckle 82 can adjust the position of throttle linkage 84
relative to shaft 52. This will permit on site adjustment which may
be necessary for engine 22 power output to be trimmed to match pump
14 power demand.
[0018] The present invention provides an uncomplicated mechanism
which accounts for increases in the pump pressure caused by
changing flow rates, increases in pressure caused by engine droop
as well as suction pressure. The simple pressure activated device
of the present invention can be used to compensate for all of these
automatically. The system itself does not require multiple
adjustments for these three separate factors. This reduces the
maximum pressure for a sprinkler system without limiting designed
flow rate. Thus by utilizing the present invention, one can
dramatically reduce the cost of a sprinkler system.
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