SE2151142A1

SE2151142A1 - Arrangement in a water jet

Info

Publication number: SE2151142A1
Application number: SE2151142A
Authority: SE
Inventors: Robert Åberg
Original assignee: Minab Maskindemontering I Norr Ab
Priority date: 2021-09-20
Filing date: 2021-09-20
Publication date: 2023-03-21
Also published as: SE545717C2

Abstract

The invention relates to an arrangement (20) in a water jet (10) of a water vessel (1), the water jet (10) including a water intake (13) with an intake guard (16) and a water jet outlet (14) connected to the water intake (13) via a water flow path (15) in which an impeller (12) is arranged to provide a driving action to water passing through the water flow path (15). The arrangement (20) comprises an air pressure chamber (21) and a source of pressurised air (22) for providing pressurised air to the air pressure chamber (21), wherein the air pressure chamber (21) is connected via an air conduit (23) to an air discharge opening (31) into the water flow path (15) to provide an air pulse towards the water intake (13), the air pulse being configured to rinse the intake guard (16) from inside of the water flow path (15). The invention also relates to a water vessel and to a method of rinsing a water intake of a water jet.

Description

ARRANGEMENT IN A WATER JET TECHNICAL FIELD The invention relates to an arrangement in a water jet, and more specifically to an arrangement for rinsing an intake guard of a water intake of a water jet. The invention also relates to a water vessel including such an arrangement, and to a method of rinsing the intake guard of the water intake of a water jet. BACKGROUND ln marine transporting and water sports, water jets have become more and more popular over the latest years. Jet-skis, water scooters and boats or ships are examples of water vessels that may be driven by means of at least one water jet.

An occurring problem in such water jet driven water vessels is that the water intake of the water jet may be clogged by debris such as sea grass, seaweed, lily pads plastics or other items that may be floating around at sea. A water jet is dependent on a high flow of water passing the quickly rotating impeller that provides the driving force to the water vessel carrying the water jet. lf the water intake is clogged the function of the water jet will be fully or partly impeded depending on the level of clogging. Different means has been addressed to solve this problem, but as of today no satisfactory solution has been provided.

US 10 099 763 B1 discloses a debris shedding water jet intake grate system. The system comprises a plurality of slinger blades configured to cut and shred debris to a size that allows them to pass through water jet without interfering with the impeller of the water jet. A drawback is that in order to provide the desired shredding function the slinger blades need to be positioned outside of the grate system. Therefore, the sling blades are exposed to obstacles that may cause damage to the sling blades and further the sling blades may cause damage to water living creatures that may follow the water being drawn towards the water jet intake grate system. lt would be advantageous to achieve an arrangement and a method overcoming, or at least alleviating, at least one or some of the drawbacks of the prior art. ln particular, it would be advantageous to achieve an arrangement and a method enabling a quick and reliable manner of clearing the water intake of a water jet.

SUMMARY OF THE INVENTION lt is an object of the invention to provide an arrangement and a method that enables a quick and reliable manner of rinsing the water intake of a water jet that only requires a short stop in the operation of the water vessel.

According to a first aspect the invention relates to arrangement in a water jet of a water vessel, the water jet including a water intake with an intake guard and a water jet outlet connected to the water intake via a water flow path in which an impeller is arranged to provide a driving action to water passing through the water flow path, wherein the arrangement comprises an air pressure chamber and a source of pressurised air for providing pressurised air to the air pressure chamber, wherein the air pressure chamber is connected via an air conduit to an air discharge opening into the water flow path to provide an air pulse towards the water intake, the air pulse being configured to rinse the intake guard from inside the water flow path.

According to a second aspect the invention relates to a water vessel that comprises an arrangement as described above.

According to a third aspect the invention relates to a method of rinsing an intake guard of a water intake of a water jet of a water vessel, the water jet further comprising a jet outlet connected to the water intake via a water flow path in which an impeller is arranged to provide a driving action to water passing through the water flow path, the method comprising the step of providing an air pulse towards the water intake, the air pulse being provided from an air pressure chamber and being configured to rinse the intake guard from inside the water flow path.

An advantage of the invention according to the above aspects is that rinsing of the water intake of water jet may be achieved at will, in an effective and convenient manner for the operator of the water vessel. Specifically, the operator need not even move from his position at the navigation panel of the water vessel to operate the arrangement for rinsing the water intake. Further, the effect is instantaneous and the stop in the operation of the water vessel need not be longer than a couple of seconds.

Other embodiments and advantages will be apparent from the detailed description and the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Below, specific embodiments of the invention will be described with reference to the appended drawings, of which: Fig. 1 is a schematic view of a water vessel on which an arrangement according to the invention is provided, Fig. 2 a schematic view of a water jet of a water vessel, at which an arrangement according to the invention has been provided, and Fig. 3 is a very schematic view of a water flow path of a water jet from the inside thereof, towards the water intake of the water jet.

DETAILED DESCRIPTION OF THE SHOWN EI\/IBODII\/IENTS ln Fig. 1 a waterjet driven water vessel 1 is shown, on which an arrangement according to the invention is provided. The shown water vessel 1 is a small boat of a rescue type popularly used in sea rescue services, where the water jet provides an advantageous drive to rapidly move the water vessel on the water. The invention is however not limited to a specific type of boat but is configured for all kinds of water jet driven water vessels, including jet-skis, water scooters and boats or ships that are driven by means of at least one water jet. A water jet provides an effective manner of driving a water vessel regardless the size of the water vessel.

As is illustrated in Fig. 1, the water vessel typically includes a body with a stem portion 3, a bottom 4, and a stern portion 5. ln a conventional manner the water jet 10 is arranged at the stern 5 of the water vessel 1, with a water intake 13 at the bottom 4 of the water vessel and a water jet outlet 14 at the lower part of the stern 5, directed backwards to provide the driving force that drives the water vessel 1 forward. A control panel 6, typically a navigation panel including steering and motor controls, is arranged, preferably on a starboard part of the water vessel. ln Fig. 2 the waterjet 10 is shown in more detail, although schematically.

The water jet 10 includes a water intake 13 and a water jet outlet 14 connected to the water intake 13 via a water flow path 15 in which an impeller 12 is arranged to provide a driving action to water passing through the water flow path 15. The impeller 12 is driven by a drive unit 11 (motor) via a shaft 17 extending into the water flow path 15 from a forward part of the water flow path 15. As is schematically illustrated in Fig. 3 an intake guard 16 is arranged at the water intake 13 to protect the impeller 12 from debris.

As described in the background part of this specification the intake guard 16 may at times become partially or fully clogged during operation. The invention is based on the idea to remove this clogging in a rapid and effective manner.

An arrangement 20 configured to rinse the intake guard 16 is therefore provided. The arrangement comprises an air pressure chamber 21 and a source of pressurised air 22 for providing pressurised air to the air pressure chamber 21. ln the shown embodiment, the source of pressurised air 22 is a compressor, but it may also advantageously be comprised of a gas cylinder, for example a gas cylinder of type used in diving, such as a standard scuba cylinder with an internal pressure of about 100 to 300 bars. Both the type and size of the source of pressurised air 22 and the size of the air pressure chamber 21 may be adapted to the size of the water vessel and/or the water jet 10. The size of a standard scuba cylinder typically ranges from 3 to 18 litres, but gas cylinders are also available in smaller sizes of 0.5, 1.5 and 2.0 litres, which may be sufficient on a small water vessel where space is limited and/or where the weight shall be held to a minimum. ln the shown embodiment one water jet 10 is arranged on the illustrated water vessel 1, which typically is of a size of a small rescue boat. For such a water vessel it has proven sufficient with an air pressure chamber 21 of the size of 6 litres with the source of pressurised air set to deliver a pressure of approximately 6 bar. However, as suggested above, both the volume of the air pressure chamber 21 and the pressure inside it may be adapted to the size of the water vessel and/or the water jet 10.

The air pressure chamber 21 is connected via an air conduit 23 to an air discharge opening 31 that opens into the water flow path 15 to provide an air pulse towards the water intake 13. The air pulse from the air pressure chamber 21 is of such magnitude that it provides a boost configured to rinse the intake guard 16 from the inside the water flow path 15.

For a water vessel that comprises a plurality of water jets, an arrangement may be provided for each water jet, or one arrangement may be provided for more than one water jet. Preferably, an arrangement for more than one water jet is arranged to rinse one water jet intake at a time, wherein separate and closable air conduits may be provided from the air pressure chamber 21 to the respective water flow paths of each water jet, such that the air impulse from the air pressure chamber 21 is selectively connected to any one water flow path per activation.

As is schematically illustrated in Fig. 2 a blow-off valve 27 is arranged to selectively open the air conduit 23 from the air pressure chamber 21 to the water flow path 15 of the water jet 10.

A valve controller 29 is arranged at a control panel 6 of the water vessel 1 to open the blow-off valve 27. The control panel 6 may be a part of the navigation panel including steering and motor controls, or it may be a separate panel arranged at any location in the water vessel that is practical or convenient for the operator of the vessel.

A safety valve 28 is arranged in the air conduit 23 to block water from passing through the air conduit 23 from the water flow path 15 during operation of the water jet 10. The safety valve 28 may be pressure controlled such that it closes whenever the pressure in the air pressure chamber 21 reaches below a certain threshold, such as for example 3 bar. Then, automatically when the pressure in the air pressure chamber 21 reaches above 3 bar it opens so as to allow passing of an air pulse from the air pressure chamber 21 into the water flow path 15 whenever commanded. A control line 24' may be provided to control the safety valve 28 by indicate the pressure that has been built up by the source of pressurised air 22.

As is best shown in Fig. 2, the air discharge opening 31 is preferably arranged opposite to the water intake 13 to direct the air pulse directly towards the water intake 13. Certainly, the pressure of the air pulse is of such magnitude that it will provide a strong boost towards the water intake 13 so as to effectively rinse the intake guard from debris, such as sea grass, seaweed, lily pads or plastics regardless of its position in the water flow path 15. However, the effect will be even more effective if the air pulse is directed directly towards the water intake 13, opposed to the direction of the water passing into the water intake 13 during operation of the water jet 10.

A pressurised air controller 30 is preferably arranged to control the source of pressurised air 22, so achieve refilling of the air pressure chamber 21 when desired. The pressurised air controller 30 may be arranged to command the source of pressurised air 22 to refill the air pressure chamber 21 as soon as the pressure chamber 21 has been emptied by control of the blow-off valve 27, or it may include an activation control to activate the source of pressurised air 22 at will. Such an activation control is preferably arranged at a control panel 3 of the water vessel 1. The pressurised air controller 30 may be an activation button that forms a part of a navigation panel of the water vessel, or it may be arranged as a separate control panel arranged at any location in the water vessel that is practical or convenient for the vessel operator During operation of the water vessel 1, whenever the mate or operator of the water vessel 1, observes or suspects that the water intake is inhibited by debris blocking at least a portion of the intake guard 16, the operator may decide to provide an air pulse towards the water intake 16, the air pulse being provided from the air pressure chamber 21 and being configured to rinse the intake guard 16 from inside the water flow path 15. ln order to achieve the air pulse, a prior step of filling the air pressure chamber 21 with pressurized air is needed. This is advantageously achieved by means of the source of pressurised air 22 arranged on the water vessel 1 as described above, but may also be achieved in other manners.

As indicated above the operation of the air pressure chamber 21 and the source of pressurised air 22 may be fully or partly automated, or it may be manually controlled. ln the fully or partly automated version, sensors may be arranged to control the process. A first sensor may be arranged to follow the action of the water jet 10. This may be achieved by monitoring the effect of the water jet for example by comparing the power of the drive unit driving the impeller to the acceleration of the vessel. As an alternative, the water flow through the water flow path 15 up stream of the impeller may be monitored by a flow sensor. Nevertheless, the effect of the water jet 10 and the occurrence of debris blocking the water intake may be easily monitored, and an experienced operator will normally understand when there is risk of such blocking, such that an air pulse from the air pressure chamber 21 may be activated. Further, as described above, the activation of the source of pressurised air 22 may be manually controlled and fully or partly governed by the pressure in the air pressure chamber 21. Of course, the source of pressurised air 22 is preferably set to deliver a pressure only up to a certain threshold, which may for example be set at 6 Bar.

The activation of the air pulse from the air pressure chamber 21 is quick and the effect is immediate. With a source of pressurised air 22 of a manageable size the air pressure chamber 21 may be filled in less than 30 seconds. However, the refilling of the air pressure chamber 21 may be completed when the water jet is in operation and whilst the water vessel 1 is in motion such that it will not interfere with the operation of the water vessel 1. The controls of the arrangement may preferably be driven by a standard battery pack already comprised in the water vessel. lf the source of pressurised air 22 includes a Compressor, this may also be driven by the same standard battery pack, or by another power source arranged on the water vessel.

Above, the invention has been described with reference to specific embodiments. The invention is however not limited to these embodiments. lt is obvious to a person skilled in the art that other embodiments are possible within the scope of the following claims.

Claims

1._ An arrangement (20) in a waterjet (10) of a water vessel (1), the waterjet (10) including a water intake (13) with an intake guard (16) and a waterjet outlet (14) connected to the water intake (13) via a water flow path (15) in which an impeller (12) is arranged to provide a driving action to water passing through the water flow path (15), characterised in that the arrangement (20) comprises an air pressure chamber (21) and a source of pressurised air (22) for providing pressurised air to the air pressure chamber (21 ), wherein the air pressure chamber (21) is connected via an air conduit (23) to an air discharge opening (31) into the water flow path (15) to provide an air pulse towards the water intake (13), the air pulse being configured to rinse the intake guard (16) from inside the water flow path (15). _ The arrangement (1) according to claim 1, wherein a blow-off valve (27) is arranged to selectively open the air conduit from the air pressure chamber (21) to the water flow path (15). _ The arrangement (1) according to claim 2, further including a valve controller (29) arranged at a control panel (3) of the water vessel (1) to open blow-off valve (27). _ The arrangement (1) according to anyone of the preceding claims, wherein a safety valve (28) is arranged in the air conduit (23) to block water from passing the air conduit (23) from the water flow path (15) during operation of the water jet (1 O). _ The arrangement (1) according to anyone of the preceding claims, wherein the air discharge opening (31) is arranged opposite the water intake (13) to direct the air pulse directly towards the water intake (13). _ The arrangement (1) according to anyone of the preceding claims, wherein a pressurised air controller (30) is arranged at a control panel (3) of the water vessel (1) to control the source of pressurised air (22) to refill the air pressure chamber (21) when desired. _ A water vessel (1) characterised in that it comprises an arrangement (1) according to anyone of the preceding claims. _ A method of rinsing an intake guard (16) of a water intake (13) of a water jet (10) of a water vessel (1), the water jet (10) further comprising a jet outlet (14) connected to the water intake (13) via a water flow path (15) in which an impeller (12) is arranged to provide a driving action to water passing through the water flow path (15), the method comprising the step of providing an air pulse towards the water intake (13), the air pulse being provided from an air pressure chamber (21) and being configured to rinse the intake guard (16) from inside the water flow path (15). . The method according to claim 8, further comprising the step of fi||ing the air pressure chamber (21) with pressurized air by means of a source of pressurised air (22) arranged on the water vessel (1).