Underwater trenching apparatus and pumping apparatus

Abstract

An underwater trenching apparatus and pumping apparatus includes: first and second pumps and a trench-cutting jetting tool with first and second sections, the first pump having an inlet for fluid connection with a source of water and an outlet fluidly connected to the first section of the jetting tool, the second pump having an inlet for fluid connection with a source of water and an outlet fluidly connected to the second section of the jetting tool, wherein the outlet of the first pump is fluidly connected to the inlet of the second pump by valve means that is operable to divert at least a portion of an outlet flow of the first pump to the inlet of the second pump.

Claims

1. A pumping apparatus for use in an underwater trenching apparatus, comprising a first pump having an inlet for fluid connection through a first intake with a source of liquid and an outlet for fluid connection to the first section of a jetting tool and a second pump having an inlet for fluid connection through a second intake with a source of liquid and an outlet for fluid connection to the second section of a jetting tool, wherein the outlet of the first pump is fluidly connected to the inlet of the second pump by valve means that is operable to divert at least a portion of an outlet flow of the first pump from the first section of the jetting tool to the inlet of the second pump.

2. Apparatus as claimed in claim 1 comprising a third pump having an inlet for fluid connection with a source of liquid and an outlet fluidly connected to or for fluid connection with a third section of the or a jetting tool, wherein the outlet of the second pump is fluidly connected to the inlet of the third pump by the or a further valve means of the apparatus that is operable to divert at least a portion of an outlet flow of the second pump to the inlet of the third pump.

3. Apparatus as claimed in claim 1, wherein the or each valve means is adjustable, in use, to change or vary the proportion of the outlet flow that is diverted.

4. Apparatus as claimed in claim 1, wherein the or each valve means comprises a mixing valve.

5. Apparatus as claimed in claim 1, wherein the or each valve means is operable to close, in use, the fluid connection between the outlet of the pump and the relevant section of the jetting tool before or as a fluid connection is opened between the outlet of the pump and the inlet of the other pump.

6. Apparatus as claimed in claim 1, wherein the or each valve means comprises a directed flow or plug valve.

7. Apparatus according to claim 1 comprising control means operatively connected to and configured to control the or each pump.

8. Apparatus according to claim 7, wherein the or each valve means comprises a valve with an actuator that is operatively connected to and controllable automatically by the control means.

9. Apparatus as claimed in claim 2 comprising a check valve means having an inlet for fluid connection with the source and an outlet fluidly connected to the inlet of the second pump, wherein the check valve means is configured to allow fluid flow from the source to the inlet of the second pump and to prevent fluid flow to or toward the source.

10. Apparatus as claimed in claim 9 comprising a further check valve means having an inlet for fluid connection with the source and an outlet fluidly connected to the inlet of the third pump, wherein the further check valve means is configured to allow fluid flow from the source to the inlet of the third pump and to prevent fluid flow to or toward the source.

11. Apparatus according to claim 1 comprising a pressure boost means operatively connected to the inlet of each of the first and second pumps and operable, where the ambient pressure is insufficient substantially to prevent cavitation in the first or second pump, to locally increase the pressure at the inlet thereof.

12. Apparatus according to claim 11, wherein the pressure boost means comprises one or more jet pumps.

13. Apparatus according to claim 9, wherein the connection between the or each source and the or each pump or check valve means comprises an intake filter.

14. An underwater trenching apparatus comprising: the pumping apparatus according to claim 1; and a trench-cutting jetting tool with first and second sections; the outlet of the first pump being fluid connected to the first section of the jetting tool, the outlet of the second pump being fluidly connected to the second section of the jetting tool.

15. Apparatus as claimed in claim 1, wherein the valve means includes a three-way valve positioned on a delivery line connecting the first pump to the first section of the jetting tool, the three-way valve being fluidly connected to a feed line of the second pump via a diversion line.

16. Apparatus as claimed in claim 2, wherein the outlet of the first pump is fluidly connected to the inlet of the third pump by the or a further valve means of the apparatus that is operable to divert at least a portion of an outlet flow of the first pump to the inlet of the third pump.

17. Apparatus as claimed in claim 16, wherein the outlet of each of the first, second and third pumps is fluidly connected to respective section via a delivery line, wherein the valve means includes first and second three-way valves connected in series on the delivery line connecting the first pump to the first section, and, wherein the first three-way valve is fluidly connected to a feed line of the second pump via a first diversion line, and wherein the second three-way valve is fluidly connected to the feed line of the third pump via a second diversion line.

18. A method of operating an underwater trenching apparatus, the method comprising diverting at least a portion of the outlet flow of a first pump from the first section of a jetting tool to the inlet of a second pump fluidly connected to a second section of the jetting tool in order to increase the pressure of the outlet flow of the second pump supplied to the second section of the jetting tool, the first pump having a first intake and the second pump having a second intake.

19. Method according to claim 18 further comprising diverting at least a portion of the outlet flow of the second pump from the second section of the jetting tool to the inlet of a third pump fluidly connected to a third section of the jetting tool in order to increase the pressure of the outlet flow of the third pump supplied to the third section of the jetting tool.

20. Method according to claim 18 comprising diverting only some of the outlet flow of the first pump such that a portion of the outlet flow is supplied to the first section of the jetting tool and a further portion of the outlet flow is supplied to the inlet of the second pump.

21. Method according to claim 18 comprising varying the proportion of the outlet flow that is diverted in response to a command received by a user and/or according to varying requirements.

22. Method according to claim 18 comprising diverting the outlet flow portion of one or more of the pumps using a control means.

23. Method according to claim 18 comprising increasing locally the pressure of a fluid flow to the inlet of the first and/or second pump to inhibit cavitation thereof or therein.

24. A computer program element comprising computer readable program code means for causing a processor to execute a procedure to implement a method according to claim 18.

25. A computer readable medium having a program stored thereon, where the program is arranged to make a computer execute a procedure to implement a method according to claim 18.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

(2) FIG. 1 is a schematic representation of an underwater trenching apparatus according to an embodiment of the invention shown in a first mode of operation configured for cutting through substrates incorporating loose sands and weak clays;

(3) FIG. 2 is a schematic representation of the apparatus of FIG. 1 shown in a second mode of operation configured for cutting through substrates incorporating strong clays and hard soils;

(4) FIG. 3 is a schematic representation of an underwater trenching apparatus according to another embodiment of the invention shown in a first mode of operation configured for cutting through substrates incorporating loose sands and weak clays; and

(5) FIG. 4 is a schematic representation of the apparatus of FIG. 2 shown in a second mode of operation configured for cutting through substrates incorporating soft and intermediate clays and soils.

DETAILED DESCRIPTION

(6) Referring now to FIG. 1, there is shown an underwater trenching apparatus 1 including first, second and third pumps 2a, 2b, 2c and a jetting tool leg or sword 3 including upper, middle and lower sections 3a, 3b, 3c. Although only one is shown, the jetting tool may include multiple jet cutting legs 3, each including upper, middle and lower sections 3a, 3b, 3c. It will be appreciated by one skilled in the art that the references below to the jet cutting leg 3 and sections 3a, 3b, 3c thereof apply equally to embodiments with multiple jet cutting legs 3 each including sections 3a, 3b, 3c. The pumps 2a, 2b, 2c are of a known type and are preferably single stage pumps.

(7) In use, pressurised water supplied to each section 3a, 3b, 3c is evacuated from its respective outlet to cut trenches or holes in suitable adjacent substrates, for example a sea bed consisting of sand and/or clay and/or soil.

(8) Each of the three pumps 2a, 2b, 2c includes an inlet 20 and an outlet 21, where each inlet 20 is fluidly connected to an intake 4 via a feed line 5. The intakes 4 are disposed within a source of water and each includes a filter for preventing debris from entering the feed line 5 and hence, subsequently, any of the pumps 2a, 2b, 2c.

(9) The outlet 21 of each of the pumps 2a, 2b, 2c is fluidly connected to a respective section 3a, 3b, 3c via a delivery line 6. Thus, the first pump 2a is fluidly connected to the upper section 3a, the second pump 2b is fluidly connected to the middle section 3b and the third pump 2c is fluidly connected to the lower section 3a.

(10) The delivery line 6 connecting the first pump 2a to the upper section 3a includes first and second three-way valves 7a, 7b connected in series. The first valve 7a is fluidly connected to the feed line 5 of the second pump 2b via a first diversion line 8a. The second valve 7b is downstream of the first valve 7a and is fluidly connected to the feed line 5 of the third pump 2c via a second diversion line 8b. The delivery line 6 connecting the second pump 2b to the middle section 3b includes a third three-way valve 7c, which is fluidly connected to the feed line 5 of the third pump 2c via a third diversion line 8c.

(11) Non-return valves 9 are included in the feed lines 5 of the second and third pumps 2b, 2c, upstream of the respectively connected diversion lines 8a, 8b. Each non-return valve 9 is configured to allow fluid flow from the intake 4 to the relevant pump 2b, 2c, but to prevent fluid flow in the opposite direction.

(12) The first, second and third three-way valves 7a, 7b, 7c are operatively connected to a remotely located controller (not shown), via wireless or wired communication means. The controller may then be operated to adjust remotely the three-way valves 7a, 7b, 7c and hence alter the flow paths of water therethrough.

(13) In the first configuration shown in FIG. 1 the three-way valves 7a, 7b, 7c are configured such that each pump 2a, 2b, 2c is connected to its respective jetting leg section 3a, 3b, 3c. More specifically, the first pump 2a is only fluidly connected to the upper section 3a, the second pump 2b is only fluidly connected to the middle section 3b and the third pump 2c is only fluidly connected to the lower section 3c.

(14) In use, the pumps 2a, 2b, 2c are activated and water is drawn through the intakes 4 to the inlets 20 of the pumps 2a, 2b, 2c via the feed lines 5. The water is pumped at an increased pressure out from the pump outlets 21, through the three-way valves 7a, 7b, 7c, and thence to the respective sections 3a, 3b, 3c. In this first configuration, full flow is provided to all three sections 3a, 3b, 3c of the jetting leg 3. As a result, a relatively high water flow rate is delivered at a moderate pressure from the outlets of the sections 3a, 3b, 3c of the jetting leg 3. This configuration is useful for cutting through substrates incorporating weak clays and loose sands, where such cutting may be achieved over a relatively wide area at any given time.

(15) Referring now to FIG. 2, the apparatus 1 of FIG. 1 is shown in a second configuration in which the first three-way valve 7a has been adjusted to divert all of the pressurised water from the outlet 21 of the first pump 2a to the inlet 20 of the second pump 2b via the first diversion line 8a. The third three-way valve 7c has also been adjusted to divert all of the pressurised water from the outlet 21 of the second pump 2b to the inlet 20 of the third pump 2c via the third diversion line 8c. The non-return valves 9 prevent pressurised water from travelling back to the intakes 4.

(16) In the configuration of FIG. 2, the pumps 2a, 2b, 2c are in a series arrangement such that the pressure of flow delivered from the outlet 21 of the first pump 2a is augmented by the second pump 2b and the flow delivered from the outlet 21 of the second pump 2b is augmented by the third pump 2c. Accordingly, the pressure of flow delivered from the outlet 21 of the third pump 2c is a combination of the pressure generated in all three pumps 2a, 2b, 2c. The water pressure supplied to, and subsequently evacuated from, the lower section 3c is therefore significantly higher than in the configuration shown in FIG. 1.

(17) Advantageously, the higher pressure water is useful to cut into adjacent substrates incorporating strong clays and hard soils, which might not otherwise be abraded by the lower water pressure delivered by the configuration of FIG. 1. However, in this second configuration the flow rate is reduced considerably and therefore a narrower area may be processed at any given time.

(18) Referring now to FIG. 3, there is shown an underwater trenching apparatus 10 according to an alternative embodiment of the invention, where like features have like references and will not be described further. In this embodiment the underwater trenching apparatus 10 includes only one uptake 4, which is fluidly connected to the first inlet 11a of a jet pump 11.

(19) The jet pump 11 also includes a second, intermediate inlet 11b and an outlet 11c. The second inlet 11b of the jet pump 11 is fluidly connected the outlet 21 of the first pump 2a via a regulating line 12. The output 11c of the jet pump 11 is fluidly connected to the feed lines 5 of each of the pumps 2a, 2b, 2c. The jet pump 11 provides a variable pressure boost to the water supplied to the inlets 20 of each of the pumps 2a, 2b, 2c, thereby significantly reducing the possibility of cavitation therein. A flow control valve 13 is also included in the regulating line 12 and is operably connected to the remotely located controller (not shown) via wired or wireless communication means.

(20) In use, when the apparatus 10 is located in deep water the surrounding water pressure is relatively high and therefore the risk of cavitation within the pumps 2a, 2b, 2c is relatively low. Therefore, in deep water conditions the flow restricting valve 13 may be operated to close fluid communication between the outlet 20 of the first pump 2a and the input 11b of the jet pump 11.

(21) Conversely, when the apparatus 10 is located in shallow water the water pressure is relatively low and therefore the risk of cavitation within the pumps 2a, 2b, 2c is relatively high. Therefore, in shallow water conditions the flow restricting valve 13 may be operated to open fluid communication between the outlet 21 of the first pump 2a and the input 11b of the jet pump 11 to bleed some of the higher pressure output flow from the first pump 2a into the jet pump 11 and hence prevent or reduce the incidence of cavitation.

(22) In use, the configuration of the apparatus 10 shown in FIG. 3 delivers pressurised water to each of the sections 3a, 3b, 3c, in a similar manner to the configuration of the underwater trenching apparatus 1 shown in FIG. 1. As explained above, this arrangement is useful for cutting through adjacent substrates incorporating loose sands and weak clays.

(23) Referring now to FIG. 4, the apparatus 10 of FIG. 3 is shown with a different configuration. In this configuration, the second three-way valve 7b has been adjusted to divert all of the pressurised water from the outlet 21 of the first pump 2a to the inlet 20 of the third pump 2c via the second diversion line 8b. The second pump 2b remains unchanged and supplies fluid flow to the middle section 3b of the jetting leg 3. The second non-return valve 7b prevents pressurised water from travelling back to the output 11c of the jet pump 11.

(24) Thus, the first and third pumps 2a, 2c are in a series arrangement, whereby the pressure of water pumped from the outlet 21 of the third pump 2c to the lower section 3c is a combination of pressures generated by the first and third pumps 2a, 2c. Meanwhile, the second pump 2b behaves as before and pumps pressurised water to the middle section 3b at a similar pressure to the configuration shown in FIG. 3. Water is not pumped to the upper section 3a in the configuration of FIG. 4.

(25) Advantageously, the configuration of FIG. 4 provides an increased water pressure output from the lower section 3c in comparison with the configuration of FIG. 3. This increased water pressure output from the lower section 3c is suitable for cutting into adjacent substrates incorporating intermediate clays and soils. However, and at the same time, the middle section 3b continues to provide a pressurised water output, albeit at a lower pressure. In this way the middle section 3b may cut through adjacent substrates incorporating soft clays and soils. Usefully, this configuration increases the hardness of materials which may be cut by the apparatus 10 whilst maintaining, so far as possible, the rate with which trench cutting is achieved.

(26) It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention. For example, it will be appreciated that any useful configuration of the three-way valves 7a, 7b, 7c of the underwater trenching apparatus 1, 10 may be possible. For instance, the alternative embodiment of the apparatus 10 shown in FIG. 3 may have its three-way valves 7a, 7b, 7c adjusted in order to approximate the configuration of three-way valves 7a, 7b, 7c shown in FIG. 2 in relation to the first embodiment of the underwater trenching apparatus 1. Additionally or alternatively, the first embodiment of the underwater trenching apparatus 1 may have its three-way valves 7a, 7b, 7c configured in the manner described in relation to the alternative embodiment of the underwater trenching apparatus 10 shown in FIG. 4. The apparatus 1 according to the first embodiment may include one or more jet pumps 11 or other pressure boost means fluidly connected with one or more of the pumps 2a, 2b, 2c, with or without a check valve 13.

(27) Although three pumps 2a, 2b, 2c are shown in the above embodiments this need not be the case and the underwater trenching apparatus 1, 10 may include only two pumps 2a, 2b or more than three pumps 2a, 2b, 2c, for example four, five or six pumps. Where the underwater trenching apparatus 1, 10 includes a different number of pumps 2a, 2b, 2c to the embodiments described above, it will be appreciated that the quantity of respective sections 3a, 3b, 3c, three-way valves 7a, 7b, 7c, one-way valves 9, feed lines 5, diversion lines 8a, 8b, 8c and delivery lines 6 will be consequently altered in concert therewith.

(28) It is further envisaged and claimed that the apparatus need not include the jetting tool. For example, the present invention also relates to a pumping apparatus. The pumping apparatus may be used with jetting tools having more or less sections than the number of pumps comprised in the pumping apparatus. In such instances, the skilled person would appreciate the various connection arrangements possible.

(29) Additionally or alternatively, the supply of pressurised water to one or more of the sections 3a, 3b, 3c of the jet cutting leg 3 may be further adjustably controlled by use of one or more constriction valves, for example where such constriction valves are included in the delivery lines 6. The constriction valves may be operatively connected to a remotely located controller which may adjust the constriction of the constriction valves in order to selectively reduce or increase the flow of pressurised water to one or more of the sections 3a, 3b, 3c. In this way the pressure and flow rate of pressurised water delivered by one or more of the pumps 2a, 2b, 2c may be selectively controlled.

(30) Although the three-way valves 7a, 7b, 7c have been described above as being adjusted to divert or allow passage therethrough of all of the pressurised water this need not be the case. One or more of the three-way valves 7a, 7b, 7c may be adjusted in a step-wise or continuous manner such that a first portion of pressurised water delivered by one or more of the three-way valves 7a, 7b, 7c is passed therethrough and a second portion of the pressurised water is diverted to a diversion line 8a, 8b, 8c. Additionally or alternatively the three-way valves 7a, 7b, 7c may be manually adjustable.

(31) Although the first embodiment of the underwater trenching apparatus 1 has been described as including separate uptakes 4 for each of the pumps 2a, 2b, 2c this need not be case. The apparatus 1 may include less than three uptakes 4, for example only one uptake 4 as described in relation to the alternative embodiment of the underwater trenching apparatus 10 shown in FIG. 3.

(32) Additionally or alternatively, the jet cutting leg 3 of the underwater trenching apparatus 1, 10 may be removable and may be replaced, prior to use, by one or more alternative jet cutting legs 3, for example jet cutting legs 3 including more or less than three sections 3a, 3b, 3c. For example, an alternative jet cutting leg 3 may include only two sections 3a, 3b, an upper and a lower section 3a, 3b, and may have a shorter height than the jet cutting leg 3 described in the embodiment of FIG. 1. When the underwater trenching apparatus 1, 10 is provided with a jet cutting leg 3 having only two sections 3a, 3b one of the pumps 2a, 2b, 2c may be selectively prevented from pumping pressurised water towards the jet cutting leg, for example by a valve. Additionally or alternatively, where an underwater trenching apparatus 1, 10 includes more pumps 2a, 2b, 2c than sections 3a, 3b, 3c one or more of the three-way valves 7a, 7b, 7c may be adjusted to divert pressurised water from the output 21 of one or more pumps 2a, 2b, 2c towards the input 20 of a further pump 2a, 2b, 2c. In this way the quantity of pumps 2a, 2b, 2c which deliver pressurised water to sections 3a, 3b, 3c may be matched with the quantity of available sections 3a, 3b, 3c.

(33) It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.

(34) Throughout the description and claims of this specification, the words comprise and contain and variations of them mean including but not limited to, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

(35) Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

(36) The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.