AU742510B2 - Fire pump - Google Patents

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): WEIR ENGINEERING PTY LTD A.C.N. 000 373 339 Invention Title: FIRE PUMP The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 FIRE PUMP This invention relates to fire pumps and especially fire pumps for use at sea.

A fire on board a ship at sea is always a very dangerous occurrence. Whilst sea going vessels are surrounded by water, a pump is required to pump the water from the sea to put out the fire. It is important that these pumps be self-driven so that they do not rely on the power of the vessel. Many fire pumps have in the past been driven by small petrol engines. Some pumps require priming with the water before they operate efficiently. In war ships petrol is viewed as a hazardous substance due to its volatility. It is thus considered fire pumps driven by diesel engines are more desirable in a naval environment.

Diesel engines tend to be heavy and bulky and it has proved difficult to provide a simple, light, reliable and effective fire pump that runs on diesel.

It is these problems that have brought about the 20 present invention.

According to one aspect of the present invention there is provided a portable fire pump comprising a free standing centrifugal pump driven by a diesel engine, the pump having a housing containing an impeller, a water inlet 25 and a water discharge, the engine comprising a vertically mounted outboard motor having a drive shaft coupled to the impeller, the pump housing defining an oil sump to lubricatethe engine and the engine being cooled by the water discharge of the pump, and the pump including means to prime the pump, said means being driven by the engine.

Preferably the impeller and associated housing are designed so the pump can run dry.

An embodiment of the present invention will now be described by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic cross sectional view of a fire pump; and H:\Cgoty\Keep\Nadia\P33333 firepup.doc 13/01/99 3 Figure 2 is a detailed cross sectional view of the base of the fire pump.

In essence the fire pump 10 of this application comprises a centrifugal pump 11 driven by an outboard motor 12 that runs on diesel. There are a number of very efficient outboard motors that run on diesel. It is the aim of this invention to ensure that the pump can be driven by a proprietary outboard motor.

Outboard motors usually have the engine coupled to an elongated shaft that drives the propeller. Outboard motors of this kind are usually water cooled by use of the water in which the outboard motor operates.

The fire pump 10 comprises a cast outer housing that has a planar base 21 that allows the pump 10 to 15 freely stand on a flat surface. The housing 21 defines an oil sump 22 within the base of the housing 20 and an impeller chamber 30 which is in communication with a water inlet 31 and a water discharge as well as a suitable flanged entry 34 for a drive shaft 50 that is coupled to an 20 impeller 60 with radially projecting blades 61 that communicate with suitably profile surfaces 62 formed by the casting of the impeller casing 20 to cause, on rotation of S.the impeller 60, the pump 10 to operate in the manner of a conventional centrifugal pump. The impeller 60 is driven 25 by the vertical extending shaft 50 that extends down from a diesel engine, which is a diesel outboard motor, not shown.

The drive shaft 50 is located within the conventional housing (not shown) that would support the drive shaft of an outboard motor. This housing is bolted to the pump casing 20. The sump 22 in the base of the casing 20 is coupled to a filtered pipe 41 to allow the oil to move vertically to lubricate the working components of the diesel motor. The discharge 32 of the pump 10 has a branch line 35 that is also coupled to the diesel motor to provide water cooling of the motor. The engine oil is returned to the sump via an engine oil return 36. The impeller 60 and its association with the pump casing 20 is designed so that H:\Cgowty\Keep\Nadia\P33333.firepump.doc 13/01/99 4 the centrifugal pump can run in a dry condition without damaging the impeller 60 or the adjacent surfaces of the pump casing The fire pump 10 described herein needs to have the capacity to lift water through a lift of 6 metres.

Thus the pump will only operate if primed and it is understood that the pump should prime automatically to save delay in reaching effective efficiency. There are a number of means of priming the pump envisaged by the present invention. One mechanism is to place a venturi on the exhaust of the diesel engine and to couple the vacuum produced by the venturi to the impeller chamber via line to draw water into the pump to prime the pump. An alternative means of priming the pump is to couple the 15 impeller chamber 20 via the line 75 to an electrically driven vacuum pump that again causes water to be drawn into the pumping chamber. The electrically driven vacuum pump will be driven by the diesel outboard motor. In either case to use the fire pump an operator simply has to either 20 electrically or manually start the diesel outboard motor.

This will initially cause the centrifugal pump torun dry but will cause automatic priming through the venturi in the exhaust or the separate electric motor that drives the vacuum pump. Water will be drawn into the impeller o 25 chamber to prime the pump at which time full discharge will take place. The pump 10 has been designed so that even though it is driven by a diesel motor, it is comparatively light and portable.

The pump is designed to also serve as the oil sump for the diesel motor and the discharge of the pump is used to water cool the diesel motor. The pump is thus viewed as portable, compact, easy to start and very efficient whilst being self-priming. The use of diesel to drive the motor renders the source of fuel considerably less hazardous than would be the case of a more conventional petrol driven fire pump. The casing of the pump is designed so that it splits into two halves so that H:\Cgowty\eep\Nadia\P3333.firepump.doc 13/01/99 is can be dismantled to provide access to the impeller chamber so that if necessary the impeller can be replaced or serviced. The various moving components of the pump and associated bearings are designed to operate efficiently, notwithstanding the fact that the fire pump may only be used very occasionally.

H-\Cgowty\Keep\Nadia\P3i3333firepump.doc 13/01/99

Claims (6)

1-~ THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A portable fire pump comprising a free standing centrifugal pump driven by a diesel engine, the pump having a housing containing an impeller, a water inlet and a water discharge, the engine comprising a vertically mounted outboard motor having a drive shaft coupled to the impeller, the pump housing including an oil sump to lubricate the engine and the engine being cooled by the water discharge of the pump, and the pump including means to prime the pump, said means being driven by the engine.

2. The fire pump claimed in claim 1 wherein the impeller and associated housing define an impeller chamber, the impeller and impeller chamber being designed so the pump can run dry without damaging the pump.

3. The fire pump according to either claims 1 or 2 wherein the diesel engine has an exhaust that is coupled to a venturi that, in use, draws water to the impeller to prime the pump.

4. The fire pump according to either claims 1 or 2 wherein an auxiliary pump is driven by the diesel engine to pump water to the impeller to prime the fire pump.

The fire pump according to claim 4 wherein the auxiliary pump is an electric vacuum pump.

6. A portable fire pump substantially as described herein with reference to and as illustrated by the accompanying drawings. Jolenew/keep/speci/Claims P33333 7/09/01