Trench Cutter

Abstract

The trenching device (1) comprises a body (11), one or more fluid pressurizing means, a trench-forming jet tool (14) extending from the body (11) and including one or more primary jet outlets (15) along its length, a first fluid passage (41) extending between at least one of the one or more fluid pressurizing means and one or more primary jet outlets (15), a jet arm (16) with one end connected to the body (11) and having one or more secondary jet outlets (165), and between at least one of the one or more fluid pressurizing means and one or more secondary jet outlets (165) The trenching device (1) comprises a primary jet setting that enables the trenching device (1) to inject fluid from one or more primary jet outlets (15) at a first pressure to cut or fluidize material adjacent to a trench-forming jet tool (14) and form a trench (TR), and a secondary jet setting that enables the trenching device (1) to inject fluid from one or more secondary jet outlets (165) at a second pressure higher than the first pressure to cut or fluidize material adjacent to the secondary jet outlets (165).

Description

Technical Field

[0001] The present invention relates to a trenching device. In particular, but not limited thereto, the present invention relates to a trenching device having a primary jet setting and a secondary jet setting.

Background Art

[0002] Forming a trench in the ground is a well-known requirement and is typically used for laying public supply means such as oil, gas, water pipes, etc., and power and communication cables. In an underwater environment, trenching is frequently performed for laying pipes and cables, and usually a device specially designed or modified to cope with underwater conditions such as the nature of the seabed is used. Here, "seabed" refers to the bottom of a water area such as a sea, a lake, or a river, unless otherwise specified.

[0003] A variety of devices for cable laying and burial are available and can be selected according to the environment and specific requirements (such as seabed conditions and burial depth). Various devices for constructing trenches and laying cables and pipes are known in the technical field. These include plow blade type soil cutting devices, jet devices, mechanical cutters (such as chain cutters), etc. Jet devices are generally suitable for soft and loose soils, while mechanical cutting is generally suitable for hard and dense soils, such as soils with a high clay content. The soil cutting device is mounted on a device that moves on the ground or the seabed in a self-propelled or externally powered manner. For example, the trench cutting device may be towed by a tractor or a ship on the sea surface, or may be integrally incorporated into a towing unit.

Summary of the Invention

Problems to be Solved by the Invention

[0004] During trench cutting with jet equipment, encounters with hard or dense ground can occur. This can reduce cutting speed, or in some cases, completely stop the cutting process. To address this problem, the use of mechanical cutters designed to cut hard ground is known. However, changing cutters (i.e., switching from jet equipment to mechanical cutters) slows down trench cutting progress, especially because it requires the installation and use of guards to protect laid materials from the mechanical cutter. Furthermore, mechanical cutters are often too heavy to be mounted on small jet cutting vehicles, requiring the entire vehicle and mother ship to be replaced with a mechanical cutting vehicle. Therefore, the presence of hard materials in soft seabed is a factor that hinders the achievement of efficient and economical trench cutting operations.

[0005] It would be beneficial to overcome at least some of these limitations. [Means for solving the problem]

[0006] According to a first aspect of the present invention, a trenching apparatus is provided, for example, the trenching apparatus is The main unit and One or more fluid pressurizing means, A trench-forming jet tool extending from the main body and including one or more, for example, multiple primary jet outlets along its length, A first fluid passage extending between at least one of one or more fluid pressurizing means and one or more primary jet outlets, A jet arm, one end of which is connected to the main body, has one or more, for example, multiple secondary jet outlets, A second fluid passage extending between at least one of one or more fluid pressurizing means and one or more secondary jet outlets, A trenching apparatus includes a primary jet setting that is operable to inject fluid at a primary pressure from one or more primary jet outlets to cut or fluidize material adjacent to a trench-forming jet tool to form a trench, The trenching apparatus comprises a secondary jet setting that can be operated to inject fluid from one or more secondary jet outlets at a second pressure higher than the first pressure, thereby cutting or fluidizing material adjacent to the secondary jet outlet.

[0007] In other words, the trenching device can be operated with both primary and secondary jet settings.

[0008] In this specification, "arm" refers to a structure that protrudes from a larger structure. For example, in the context of the trenching apparatus described, the jet arm protrudes from the body of the trenching apparatus.

[0009] The jet arm may be deployable. That is, the jet arm may be configured to deploy in the secondary jet setting for the operation of the trenching device.

[0010] The trenching device may be a trenching device for underwater or seabed use. The fluid may be water from the body of water surrounding the trenching device at the time of use. The trench-forming jet tool may be a jet sword.

[0011] Advantageously, the trench-forming jet tool provides a means for forming trenches in, for example, soft clay or sand. Furthermore, one or more secondary jet outlets provide a means for concentrating cutting or fluidization at their respective locations. These secondary jet outlets can be used, for example, when encountering hard or compacted materials, which cannot be efficiently or completely cut or fluidized by the primary jet outlet.

[0012] The trenching device may be able to operate with a secondary jet setting independently of the primary jet setting.

[0013] In the primary jet configuration, the first fluid passage is open, and one or more of the corresponding fluid pressurizing means may be in operation.

[0014] In the secondary jet configuration, the second fluid passage is open, and one or more of the corresponding fluid pressurizing means may be in operation.

[0015] In the primary jet configuration, the second fluid passage may be closed, and / or one or more of the corresponding fluid pressurizing means may be inactive.

[0016] The trenching device may include a controller or be capable of communicating with a controller. The controller is When the trenching device is operating with the primary jet setting, a parameter indicating the speed at which the trench is formed by the trench-forming jet tool is determined. Determine whether that parameter is below the speed threshold. If that parameter falls below a speed threshold, the trenching device may be configured to output a notification or instruction to operate at the secondary jet setting.

[0017] Notifications may be displayed on the user interface. Notifications may instruct or suggest the operator to operate the trenching device with the secondary jet setting.

[0018] The instructions may be part of an automated system. The instructions may cause the trenching device to continue operating at the primary jet setting.

[0019] In one embodiment, if a parameter is greater than or equal to a speed threshold, the controller may be configured to output a notification or instruction for the trenching device to operate at the primary jet setting.

[0020] This parameter may be, for example, the speed at which the trench is formed, such as the length of the trench formed per unit time, or the time required for the trench to advance a predetermined distance. The speed at which the trench is formed may be measured by measuring the speed of the trenching device on the floor surface.

[0021] The parameter may be the first parameter. The speed threshold may be the first speed threshold.

[0022] The controller further when the trenching device is operating in the secondary jet setting, determines a second parameter indicating the speed at which the material is cut or fluidized by one or more secondary jet outlets, determines whether the second parameter is greater than or equal to a second speed threshold, and may be configured to output a notification or an instruction when the second parameter is greater than or equal to the second speed threshold.

[0023] The notification may instruct the trenching device to operate in the primary jet setting. The notification may be sent to the operator via the user interface. The instruction may be part of an automation system. The instruction may cause the trenching device to operate in the primary jet setting.

[0024] In one embodiment, when the parameter is below the second speed threshold, the controller may be configured to output a notification or an instruction that the trenching device should operate in the secondary jet setting.

[0025] The notification may be output to the user interface. The notification may instruct or suggest to the operator that the trenching device continue to operate in the secondary jet setting.

[0026] The instruction may be part of an automation system. The instruction may cause the trenching device to continue to operate in the secondary jet setting.

[0027] The trenching device may be used in an automated system. The trenching device may automatically switch from secondary jet settings to primary jet settings and / or vice versa based on a command.

[0028] The second parameter may be the rate at which the material is cut or fluidized by injecting fluid from one or more secondary jet outlets, for example, the volume of material cut or fluidized per unit time by injecting fluid from one or more secondary jet outlets.

[0029] The rate at which a trench is formed by a trench-forming jet tool, and / or the rate at which the material is cut or fluidized by the injection of fluid from one or more secondary jet outlets, may be measured or estimated by one or more sensors communicating with a controller. The sensors may be accelerometers, cameras, pressure sensors, load cells, or other suitable feedback means.

[0030] The trench-forming jet tool may be rotatably mounted to the main body, thereby allowing the trench-forming jet tool to rotate around one or more axes. When the trenching device is positioned on a horizontal plane, one of the one or more axes is substantially horizontal. One of the one or more axes may be perpendicular to the central axis of the trench-forming jet tool. One of the one or more axes may be perpendicular to the central axis of the trench-forming jet tool so that the trench-forming jet tool can rotate between a storage position and a trench-cutting position. When the trenching device is positioned on a horizontal plane, one of the one or more axes may be substantially vertical.

[0031] Multiple primary jet outlets may consist of nozzles, such as water nozzles. One or more secondary jet outlets may consist of nozzles, such as water nozzles.

[0032] The secondary jet outlet may be rotatably mounted relative to the jet arm, thereby allowing the secondary jet outlet to rotate relative to the jet arm.

[0033] A first fluid passage may be provided by a first conduit. A second fluid passage may be provided by a second conduit. Both the first and second conduits may be fluidly in communication with one of the fluid pressurizing means. The first and second conduits may be connected to a common outlet conduit connected to either of the fluid pressurizing means. The first and second conduits may be connected to a common outlet conduit connected to either of the fluid pressurizing means in a two-way valve. The first conduit may extend along a trench-forming jet tool. The second conduit may extend along a jet arm.

[0034] The diameter of the second conduit may be less than 500 mm, for example, between 100 mm and 300 mm. The second conduit may consist of multiple pipe sections connected by rotatable joints. The second conduit may consist of a hose, for example, a flexible hose.

[0035] One or more fluid pressurizing means may comprise a first fluid pressurizing means and a second fluid pressurizing means. The first fluid passage may extend between the first fluid pressurizing means and one or more primary jet outlets. The second fluid passage may extend between the second fluid pressurizing means and one or more secondary jet outlets.

[0036] A second fluid passage extends between the first and second fluid pressurizing means, so that when the trenching device is operating in a secondary jet setting, fluid may flow from the first fluid pressurizing means to the second fluid pressurizing means along the second fluid passage, and then from the second fluid pressurizing means to one or more secondary jet outlets along the second fluid passage. The second fluid passage may be partially provided by a third conduit extending between the first and second fluid pressurizing means. Advantageously, the first fluid pressurizing means may function as a primer for the second fluid pressurizing means.

[0037] The first fluid pressurizing means may be a first pump. The second fluid pressurizing means may be a second pump. The second fluid pressurizing means may be a fluid pressure intensifier.

[0038] For example, a fluid pressure booster has an inlet that receives fluid at a relatively low pressure and a relatively high flow rate, and an outlet that outputs fluid at a relatively high pressure and a relatively low flow rate.

[0039] The trenching device may include a turbine that is fluidically connected to a first pump and mechanically coupled to a fluid intensifier. The turbine may be driven by the fluid flow from the first pump and configured to drive the fluid intensifier.

[0040] The trenching device may include at least one valve, such as an operating valve, solenoid valve, or diver operating valve, located in the second fluid passage. When the trenching device is operating in the primary jet setting, at least one valve may block the fluid flow along the second fluid passage. Advantageously, the second fluid pressurizing means is shielded from the first pressure.

[0041] The trenching device may include at least one valve, such as a solenoid valve, located within the first fluid passage. When the trenching device is operating in a secondary jet setting, at least one valve may block the fluid flow along the first fluid passage.

[0042] The trench-forming jet tool may extend from the main body at a first position. The jet arm may be connected to the main body at a second position, separate from the first position, for example, at a distance.

[0043] The second position may be in front of or near the trenching device during use. An advantage is that, if hard material is encountered, the jet arm can be used to cut or fluidize the hard material in front of the trench currently being formed.

[0044] The jet arm may be movable between a retracted state and an operational state. When operating with the secondary jet setting, the jet arm may be in the operational state.

[0045] Preferably, the jet arm may be retracted so as not to interfere with cable laying work in the primary jet setup.

[0046] The jet arm may be an articulated arm. Advantageously, one or more secondary jet outlets may be positioned to concentrate the ejected fluid onto a specific (e.g., hard) material.

[0047] The jet arm may comprise multiple arm sections connected by rotatable joints. One end of each arm section may be attached to the main body. The jet arm may include an actuator associated with each rotatable joint, and each actuator may be configured to actuate at least one arm section attached to the corresponding rotatable joint around the corresponding rotatable joint. There may be two, three, four, five, six or more arm sections. Preferably, the jet arm may be capable of complex movements.

[0048] In the retracted state, the arm sections may be stacked and nearly parallel to each other. Advantageously, the jet arms may occupy a small footprint in the retracted state.

[0049] At least one of the one or more secondary jet outlets may be attached to the arm furthest from the arm attached to the main body. Alternatively, all of the multiple secondary jet outlets may be attached to the arm furthest from the arm attached to the main body.

[0050] The jet arm may be rotatably mounted to the main body. The trenching device may include an actuator connected between the jet arm and the main body. The actuator may be configured to move the jet arm relative to the main body.

[0051] The first pressure may be less than 20 bar, for example, in the range of 4 to 16 bar. The second pressure may be less than 150 bar, for example, in the range of 12 to 120 bar.

[0052] According to a second aspect of the present invention, a method for forming a trench underwater or on the seabed is provided, and this method is A step of installing a trenching device at the bottom where the trench will be formed, The trenching apparatus is operated in a primary jet setting in which material adjacent to a trench-forming jet tool extending from the body of the trenching apparatus to the bottom and forming a trench is cut or fluidized, and the cutting or fluidization of the material adjacent to the trench-forming jet tool is performed by injecting fluid at a first pressure from one or more primary jet outlets arranged along the length of the trench-forming jet tool. The trenching apparatus is operated in a secondary jet setting in which material adjacent to one or more secondary jet outlets of the jet arm of the trenching apparatus is cut or fluidized, with one end of the jet arm connected to the body of the trenching apparatus, and the cutting or fluidization of material adjacent to one or more secondary jet outlets is performed by injecting fluid from one or more secondary jet outlets at a second pressure higher than the first pressure.

[0053] An advantage of this method is that cutting operations can be continued without the need to deploy other vehicles, such as mechanical trenching equipment.

[0054] In this specification, "arm" refers to a structure that protrudes from a larger structure. For example, in the context of the trenching apparatus described, the jet arm protrudes from the body of the trenching apparatus.

[0055] The fluid may be water from the body of water surrounding the trenching device. The trench-forming jet tool may be a jet sword.

[0056] This delicious, The process involves determining a parameter that indicates the speed at which a trench is formed by the trench-forming jet tool when operating in the primary jet setting, The process of determining whether that parameter is below the speed threshold, If that parameter is above the speed threshold, the trenching device is kept running with the primary jet setting. The method includes the step of operating the trenching device with a secondary jet setting if the parameter falls below a speed threshold.

[0057] The parameter may be the rate at which the trench is formed, for example, the length of the trench formed per unit time. The rate at which the trench is formed may be determined by the speed at which the trenching device moves across the floor surface.

[0058] This method, A step of determining a second parameter that indicates the rate at which the material is cut or fluidized by one or more secondary jet outlets when operating in a secondary jet setting, A step to determine whether the second parameter exceeds the second speed threshold, If the second parameter is below the second velocity threshold, the trenching device is kept running with the secondary jet setting. The procedure may also include the step of operating the trenching device with the primary jet setting if the second parameter is greater than or equal to the second velocity threshold.

[0059] The second parameter may be the rate at which the material is cut or fluidized by injecting fluid from one or more secondary jet outlets, for example, the volume of material cut or fluidized per unit time by injecting fluid from one or more secondary jet outlets.

[0060] The rate at which a trench is formed by a trench-forming jet tool, and / or the rate at which the material is cut or fluidized by the injection of fluid from a secondary jet outlet, may be measured or estimated by one or more sensors communicating with a controller. The sensors may be accelerometers, cameras, pressure sensors, load cells, or other suitable feedback means.

[0061] The trenching device may operate with a secondary jet setting, independently of the primary jet setting.

[0062] The step of injecting fluid from one or more primary jet outlets may be performed by using a first fluid pressurizing means to move the fluid along a first fluid flow path extending between the first fluid pressurizing means and the primary jet outlets. The step of injecting fluid from one or more secondary jet outlets may be performed by using a second fluid pressurizing means to move the fluid along a second fluid flow path extending between the second fluid pressurizing means and one or more secondary jet outlets.

[0063] The second fluid passage may extend between the first fluid pressurizing means and the second fluid pressurizing means. The process of injecting fluid from one or more secondary jet outlets may be carried out by moving the fluid from the first fluid pressurizing means to the second fluid pressurizing means along the second fluid passage, and then moving the fluid from the second fluid pressurizing means to one or more secondary jet outlets along the second fluid passage. Advantageously, the first fluid pressurizing means may function as a primer for the second fluid pressurizing means.

[0064] When injecting fluid from one or more primary jet outlets, the fluid may be prevented from flowing along the second fluid passage to one or more secondary jet outlets by closing at least one valve located in the second fluid passage.

[0065] When a fluid is injected from one or more secondary jet outlets, the fluid may be prevented from flowing along the first fluid passage to one or more primary jet outlets by closing at least one valve located in the first fluid passage.

[0066] When the trenching device is operated with a secondary jet setting, the method may include the step of moving one or more secondary jet outlets relative to the body of the trenching device to position one or more secondary jet outlets adjacent to the material to be cut or fluidized.

[0067] When the trenching device switches from primary jet setting to secondary jet setting, the jet arm moves from a retracted state to an operational state, in which case one or more secondary jet outlets may be positioned adjacent to the material being cut or fluidized.

[0068] According to a third aspect of the present invention, a jet arm for attachment to a trenching device is provided, the jet arm is Articulated arm and At least one rotatable joint provided along the length of the articulated arm, An actuator associated with at least one rotatable joint, each actuator configured to move at least a portion of an articulated arm around its respective rotatable joint, thereby causing the water jet outlet to move relative to the mounting means, Mounting means for attaching an articulated arm to a trench cutting vehicle, Multiple water jet outlets attached to an articulated arm, The present invention comprises a conduit extending along an articulated arm, having a conduit connector at its first end and connected to a plurality of water jet outlets, the conduit connector being for connecting the conduit to a water pressurizing means.

[0069] The mounting means may be located at the end of the articulated arm.

[0070] In this specification, "arm" refers to a structure that protrudes from a larger structure. For example, in the context of the trenching apparatus described, the jet arm protrudes from the body of the trenching apparatus.

[0071] An articulated arm may comprise multiple arm sections connected by rotatable joints. One end of an arm section may be provided with a mounting means. A jet arm may comprise an actuator associated with each rotatable joint, and each actuator may be configured to actuate at least one arm section attached to the corresponding rotatable joint, rotating it around the corresponding rotatable joint. There may be two, three, four, five, six or more arm sections.

[0072] The jet arm may include a main actuator associated with a mounting means, which may be configured to move the articulated arm relative to the trenching device when the jet arm is attached to the trenching device.

[0073] The jet arm may be movable between a stowed state and an operational state. In the stowed state, the arm sections may be stacked and substantially parallel to each other.

[0074] Multiple water jet outlets may be mounted on the arm furthest from the mounting means.

[0075] According to a fourth embodiment of the present invention, a jet cutting system is provided comprising a jet arm and a water pressurizing means having an inlet and outlet that can be connected to or connected to a conduit connector.

[0076] To avoid any doubt, any of the features described herein apply equally to all aspects of the present invention. For example, a trenching apparatus may include one or more of any features of a jet arm, and / or a method may include one or more of any features or steps relating to one or more of any features of the trenching apparatus or jet arm.

[0077] A further aspect of the present invention provides a computer program element that includes computer-readable program code means for causing a processor to perform a procedure that carries out one or more steps of the above method.

[0078] Another aspect of the present invention is to provide the above-mentioned computer program elements embodied in a computer-readable medium.

[0079] A further aspect of the present invention is to provide a computer-readable medium storing a program configured to cause a computer to perform one or more steps of the above-described method.

[0080] Another aspect of the present invention provides control means or control system or controller including the above-mentioned computer program elements or computer-readable media.

[0081] Within the scope of this application, the various aspects, embodiments, examples, and alternatives described in the preceding paragraph, claims, and / or the following description and drawings, in particular their individual features, are expressly intended to be adopted independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, provided that those features do not contradict each other. To avoid doubt, the terms “possible,” “and / or,” “for example,” “example,” and similar terms used herein should be interpreted non-restrictively, and such features do not necessarily have to exist. In fact, any combination of any features, whether expressly claimed or not, is expressly assumed without departing from the scope of the invention. The applicant reserves the right to modify the initially filed claims or to file new claims accordingly. This includes the right to modify the initially filed claims to rely on or incorporate features of other claims that were not originally claimed as such. [Brief explanation of the drawing]

[0082] Embodiments of the present invention will be described illustratively with reference to the accompanying drawings. [Figure 1] This is a schematic diagram of a trenching apparatus according to the first embodiment of the present invention. [Figure 2] Figure 1 is a schematic diagram showing the jet arm of the trenching device in operation. [Figure 3] Figure 2 is a schematic diagram showing the jet arm in its retracted state. [Figure 4] Figure 2 is a schematic diagram of the jet arm with a conduit extending along it. [Figure 5] This is a schematic diagram of a trenching apparatus according to a second embodiment of the present invention. [Figure 6] Figure 1 or Figure 4 is a front view of the trenching apparatus. [Figure 7] This is a schematic diagram of a first embodiment of a pressurizing means used in a trenching apparatus. [Figure 8] This is a schematic diagram of a second embodiment of a pressurizing means used in a trenching apparatus. [Figure 9] This is a schematic diagram of a third embodiment of a pressurizing means used in a trenching apparatus. [Figure 10] This is a schematic diagram of a fourth embodiment of a pressurizing means used in a trenching apparatus. [Figure 11] This is a schematic diagram of a fifth embodiment of a pressurizing means used in a trenching apparatus. [Modes for carrying out the invention]

[0083] Figure 1 shows a trenching device 1. In this example, it is a seabed trenching device. The trenching device 1 forms a trench TR and, in this example, lays an elongated product E in the trench TR. The elongated product E may be a pipe or a cable. The trenching device 1 has a main body 11 and one or more fluid pressurizing means (not shown), which will be broadly referred to as "pressurizing means" below. The pressurizing means has one of several configurations, for example, one or more pumps or fluid intensifiers, and different configurations will be explained later with reference to Figures 7 to 11. Any of these pressurizing means can be used in the trenching device 1 of this example.

[0084] In this example, the main body 11 is connected to a surface vessel (not shown) by a mooring rope T. The trenching device 1 is equipped with a series of tracked wheels 12 for moving on the seabed or floor surface F. It will be understood that the trenching device may also be equipped with skids for moving on the floor surface F, either separately or in conjunction with the tracked wheels 12. The trenching device 1 is propelled on the floor surface F by any suitable means, such as driving the tracked wheels 12 or towing the trenching device 1. When in use, the trenching device 1 moves forward X on the floor surface F.

[0085] In this example, the trenching device 1 has a pressing device 13 that is rotatably connected to the main body 11 during use and located at the rear of the trenching device 1. The pressing device 13 pushes the elongated product E into the trench TR during use, while giving the elongated product E a predetermined radius of curvature.

[0086] The trenching device 1 has a trench-forming jet tool 14 extending from a first position on the main body 11. In this example, the trench-forming jet tool 14 is rotatably mounted on the main body 11 and is movable between a retracted position 14S and a trench-cutting, deployment, and operation position 14D along the direction of the arrow 14M shown in Figure 1. In this example, the trench-forming jet tool 14 is rotatable about a first axis A1 which is substantially horizontal when the trenching device 1 is located on a horizontal floor surface F. In this example, the trenching device 1 includes a main actuator 17 connected to one end of the trench-forming jet tool 14, which rotates the trench-forming jet tool 14 about the first axis A1. Note that although the trench-forming jet tool 14 is shown in both the retracted position 14S and the operation position 14D in Figure 1, this is the same trench-forming jet tool 14. That is, in the example shown in Figure 1, there is only one trench-forming jet tool 14.

[0087] In this example, the trench-forming jet tool 14 is formed from two parallel members, as best shown in Figure 6. In this example, the trench-forming jet tool 14 has a plurality of primary jet outlets 15 along its entire length. It is understood that any number of primary jet outlets 15, including only one, may be provided. In this example, the plurality of jet outlets 15 are arranged along each parallel member of the trench-forming jet tool 14. The primary jet outlets 15 are connected to a pressurizing means via a first fluid passage 141, as best shown in Figure 6.

[0088] The trenching device 1 has a jet arm 16. The first end 16a of the jet arm 16 is connected to the body 11 in a second position, which is different from the first position. In this example, the second position is in front of or near the body 11 with respect to the forward direction X. In this example, the first end 16a of the jet arm 16 is connected to the body 11 by a rotatable joint. In this example, the rotatable joint allows rotation around the second axis A2 and the third axis A3, although it is also understood that the jet arm 16 may be rotatable around only one of the second axis A2 or the third axis A3. Alternatively, the rotatable joint may allow rotation around the other axis, or the rotatable joint may be a universal joint, thereby allowing rotation around any axis. Alternatively, the jet arm 16 may be connected to the body 11 by a fixed joint, i.e., a non-rotatable joint. The second axis A2 is substantially horizontal when the trenching device 1 is on a horizontal floor surface F, and is parallel to the forward direction X of the trenching device 1 when in use. The third axis A3 is substantially vertical when the trenching device 1 is on a horizontal floor surface F. In this example, the trenching device 1 includes a first actuator (not shown) for rotating the jet arm 16 about the second axis A2 and a second actuator (not shown) for rotating the jet arm 16 about the third axis A3. Here, "arm" refers to a structure that protrudes from a larger structure. For example, in the context of the trenching device described, the jet arm 16 protrudes from the body 11 of the trenching device 1.

[0089] Referring to Figures 2 and 3 with reference to Figure 1, the jet arm 16 of this example is shown. In this example, the jet arm 16 has multiple arm sections 161a, 161b, and 161c connected by rotatable joints 162a and 162b. In this example, there are three arm sections 161a, 161b, and 161c, but any number can be used. The jet arm 16 has jet arm actuators 163a and 163b associated with each rotatable joint 162a and 162b. The jet arm actuators 163a and 163b are not shown in Figure 3. When in use, activating either of the jet arm actuators 163a and 163b causes one of the arm sections 161a and 161b connected to the corresponding rotatable joint 162a and 162b to rotate relative to the other arm sections 161a and 161b connected to the corresponding rotatable joint 162a and 162b.

[0090] In this example, each jet arm actuator 163a, 163b has one end connected to the corresponding arm section 161a, 161b and the other end connected to linkage 164a, 164b. Each linkage has a first rod with one end connected to the end of a second rod, and the connection between the first and second rods is also connected to the respective jet arm actuators 163a, 163b. The other end of the first rod is connected to the arm sections 161b, 161c, to which the respective jet arm actuators 163a, 163b are also connected. The other end of the second rod is connected to the other arm sections 161b, 161c, which are connected to the respective rotatable joints 162a, 162b. This type of linkage mechanism is sometimes called a bucket linkage mechanism.

[0091] When either jet arm actuator 163a or 163b is activated, the actuators extend or retract, causing the corresponding linkages to rotate around the connection points with the arm sections 161a and 161b. This causes the other arm sections 161b, 161b, connected to the same rotatable joints 162a and 162b, to rotate around the rotatable joints 162a and 162b. Thus, the jet arm 16 is an articulated arm. The jet arm 16 is movable between the retracted state shown in Figure 3 and the operational state shown in Figure 2. In the retracted state, the arm sections 161a, 161b, and 161c are stacked and approximately parallel to each other. In either the retracted or operational state, the jet arm 16 can be rotated around the second axis A2. This allows the stacked or deployed arm sections 161a, 161b, and 161c to rotate away from the floor surface F, or, as shown in Figure 3 (when the trenching device 1 is on a horizontal floor surface F), the jet arm 16 can maintain a substantially horizontal position.

[0092] In this example, the jet arm 16 has multiple secondary jet outlets 165, but only one is visible. In this example, the secondary jet outlets are located on the arm furthest from the main body 11. At least one secondary jet outlet is located near the end of the arm furthest from the main body 11. Although only one secondary jet outlet 165 is visible in Figures 1 to 3, this is for illustrative purposes only, and any number of secondary jet outlets 165 can be provided.

[0093] The second fluid passage 166 is schematically shown by a dashed line in Figure 2 and extends between the pressurizing means and the secondary jet outlet 165. In this example, the second fluid passage is provided by a conduit (not shown) that extends along the length of the jet arm 16. The conduit can be any suitable type, such as a flexible hose. Alternatively, the conduit can be provided by a plurality of pipe sections 171a, 171b, 171c connected by rotatable joints 172a, 172b, as shown in Figure 4.

[0094] In this example, each joint 172a, 172b consists of a short pipe section with elbow joints at both ends, the elbow section being connected to pipe sections 171a, 171b, 171c associated with a particular joint. The elbow section is rotatable relative to the short pipe section. The conduit is positioned such that the axis of the short pipe section of each joint 172a, 172b is substantially perpendicular to the axis of the corresponding rotatable joints 162a, 162b of the jet arm 16. As a result, when one arm section 161a, 161b, 161c of the jet arm rotates around its respective rotatable joint 162a, 162b relative to the other corresponding arm sections 161a, 161b, 161c, the associated pipe section and elbow rotate relative to the short pipe section of the corresponding rotatable joints 172a, 172b of the conduit. In any example of a conduit, the conduit has a connector at the end furthest from the secondary jet outlet 165, which connects to further piping or hoses providing a flow path between the pressurizing means and the conduit.

[0095] Alternatively, the conduit may extend through the arm portions 161a, 161b, and 161c of the jet arm 16. That is, the arm portions 161a, 161b, and 161c may be provided as tubes or conduits so that fluid flows through them. In this case, by providing a rotatable joint as shown in Figure 4, fluid flow between adjacent arm portions 161a, 161b, and 161c can be ensured.

[0096] During operation, the trenching device 1 has a primary jet setting and a secondary jet setting. In the primary jet setting, the trenching device 1 is operable to inject fluid at a primary pressure P1 from a plurality of primary jet outlets 15. The fluid is pressurized by a pressurizing means and moves along the primary flow path, being injected to cut or fluidize the material adjacent to the trench-forming jet tool 14 to form a trench TR. Once the material adjacent to the trench-forming jet tool 14 is cut or fluidized, the trenching device 1 moves forward along the X direction and lays the elongated product E in the trench TR using a pusher 13.

[0097] In the secondary jet setting, the trenching device 1 is operable to inject fluid from the secondary jet outlet at a second pressure P2. The fluid is pressurized by a pressurizing means, moves along the second flow path, and is ejected from the secondary jet outlet to cut or fluidize the material adjacent to the secondary jet outlet. The second pressure P2 is greater than the first pressure P1. In this example, the first pressure P1 is approximately 4 bar to approximately 16 bar, and the second pressure P2 is approximately 12 bar to approximately 120 bar. For example, the second pressure P2 may be 4 to 11 bar, and the second pressure may be 12 to 120 bar. In another example, the first pressure P1 may be 4 to 16 bar, and the second pressure P2 may be 17 to 120 bar. In this example, the trenching device 1 is operable in the secondary jet setting independently of the primary jet setting, and vice versa.

[0098] In this example, to transition the trenching device 1 to the secondary jet setting, the jet arm 16 is deployed from the retracted position shown in Figure 3 to the operating position shown in Figure 2. In this way, hard or compacted materials that cannot be cut or fluidized at the primary jet outlet 15 can be cut or fluidized by concentrating the fluid injected from the secondary jet outlet at a second pressure P2. After the material to be cut or fluidized at the second pressure P2 has been cut or fluidized, the jet arm 16 is retracted to the retracted position shown in Figure 3. In this example, the jet arm 16 is deployed from the retracted position by operating the first actuator, the second actuator, and the jet arm actuators 163a and 163b.

[0099] In this example, the trenching device 1 is equipped with, or can communicate with, means such as a controller or control system. This means determines a parameter indicating the speed at which trenches TR are formed by the trench-forming jet tool 14 in the primary jet setting. In this example, the parameter is the speed at which trenches TR are formed, for example, the length of trenches TR formed per unit time. Other parameters include the pressure in the trenches TR adjacent to the trench-forming jet tool 14, or the upstream pressure of the first fluid passage used to indicate the pressure in the trenches TR adjacent to the trench-forming jet tool 14. This parameter is determined while the trenching device 1 is operating in the primary jet setting. If the parameter is determined to be above a speed threshold, the trenching device 1 continues to operate in the primary jet setting. If the parameter is determined to be below the speed threshold, for example, a notification is output to the user interface indicating that the trenching device 1 should be operated in the secondary jet setting. The operator then switches the trenching device 1 to the secondary jet setting. In other examples, the trenching device may operate on an automated system, and instead of notification, an instruction may be sent to the automated system to operate the trenching device with a secondary jet setting.

[0100] In this example, the means (or controller) also determines a second parameter in the secondary jet setting that indicates the rate at which the material is cut or fluidized by one or more secondary jet outlets. In this example, the second parameter is the rate at which the material is cut or fluidized by the injection of fluid from the secondary jet outlets, for example, the volume of material cut or fluidized per unit time by the injection of fluid from the secondary jet outlets. Other parameters include the pressure in the trench TR adjacent to the secondary jet outlet 165, or the upstream pressure of the second fluid passage used to indicate the pressure in the trench TR adjacent to the secondary jet outlet 165. When the trenching device 1 is operating in the secondary jet setting, if the second parameter is determined to be below the second velocity threshold, the trenching device 1 continues to operate in the secondary jet setting. If the second parameter is determined to be above the second velocity threshold, for example, a notification is output to the user interface indicating that the trenching device 1 should be operated in the primary jet setting. The operator then switches the trenching device 1 to the primary jet setting. Alternatively, the automated system may be instructed to switch the trenching device to the primary jet setting.

[0101] The rate at which a trench is formed by the trench-forming jet tool, and / or the rate at which the material is cut or fluidized by the injection of fluid from one or more secondary jet outlets, may be measured or estimated by one or more sensors communicating with a controller. One or more sensors may be an accelerometer and / or a camera and / or a pressure sensor and / or a load cell and / or other suitable feedback means. For example, one or more sensors may include a camera (not shown) located on the main body 11 or the trench-forming jet tool 14. Alternatively, or additionally, one or more sensors may include a pressure sensor (not shown) for measuring one or more pressures in a trench TR adjacent to the trench-forming jet tool 14 or the jet arm 16.

[0102] As an example, one of many possible operating scenarios is when the trenching device 1 is laying an elongated product E in a relatively soft material such as sand. In this case, the parameter is above the velocity threshold. This state continues until the trench-forming jet tool 14 encounters a compacted, hard material such as hard clay. When the parameter drops below the velocity threshold, the trenching device 1 switches to the secondary jet setting. In the secondary jet setting, the jet arm 16 is deployed, and the hard or compacted material is cut or fluidized by a fluid injected from the secondary jet outlet at a second pressure P2. When the second parameter exceeds the second velocity threshold, the trenching device 1 returns to the primary jet setting, and the jet arm 16 is moved to the retracted position.

[0103] It is understood that other operating modes are also possible. For example, if operating in the primary jet setting, and it is determined that the parameters fall below a speed threshold, the trenching device 1 may switch to the secondary jet setting for a predetermined time, and then return to the primary jet setting.

[0104] Referring to Figure 5, a second embodiment of the trenching device 2 is shown. The trenching device 2 of this embodiment is similar to the trenching device 1 of Figure 1, and similar features are indicated by the same reference numerals as in Figure 1, but starting with "2" instead of "1". Unlike the trenching device 1 of the previous embodiment, the trenching device 2 of this embodiment has six arm sections 261a to f in the jet arm 26, whereas the trenching device 1 of the previous embodiment had three arm sections 161a to c. These arm sections 261a to f have related link mechanisms, actuators 263a to e, and rotatable joints 262a to e, as in the previous embodiment, and the jet arm 26 and the trenching device 2 operate as described in the previous embodiment. Figure 4 shows the jet arm 26 in the retracted position 26S and the deployed position 26D, but this is for illustrative purposes only and only shows two positions of the jet arm 26. That is, the trenching device 2 has only one jet arm 26. Although the jet arm 26 of this embodiment is more complex and intricate than the jet arm 16 of the previous embodiment which has three arm sections 161a to c, the additional rotatable joints 262d and 262e provide a wider range of motion. Furthermore, it is possible to lengthen the arm sections 261a to f while maintaining a similar footprint when stacked in the storage position 26S.

[0105] Figure 6 shows front views of trenching devices 1 and 2 according to one of the previous embodiments. As can be seen from the figure, the first ends 16a and 26a of the jet arms 16 and 26 are attached to the main bodies 11 and 21 at a position offset from the centerline. This is to prevent the jet arms 16 and 26 from obstructing the path of the elongated product E. Figure 6 shows the angle θ that spreads across the entire width of the trench TR by rotating the jet arms 16 and 26 around the combination of the second axis A2 and the third axis A3. As a result, the secondary jet outlet can reach the entire width of the trench TR, or any position across the entire width of the trench TR that is formed.

[0106] Referring to Figure 7, an example of the pressurizing means 4 is shown. The pressurizing means 4 includes a first fluid pressurizing means 41 and a second fluid pressurizing means 46 separate from the first fluid pressurizing means 41. The first fluid pressurizing means 41 has a first pump 42 driven by a first motor 43 (e.g., an electric motor). The first fluid pressurizing means 41 has a first inlet 44 for supplying fluid to the first pump 42 and a first outlet 45 for discharging fluid from the first pump 42. The first inlet 44 constitutes part of the first fluid passage of the trenching device. The first outlet 45 is in fluid communication with a plurality of primary jet outlets.

[0107] The second fluid pressurizing means 46 has a second pump 47 driven by a second motor 48 (e.g., an electric motor). The second fluid pressurizing means 46 has a second inlet 49 for supplying fluid to the second pump 47 and a second outlet 410 for discharging fluid from the second pump 47. The second inlet 49 constitutes part of the second fluid passage of the trenching device. The second outlet 410 is in fluid communication with the secondary jet outlet.

[0108] When the trenching device using the first embodiment of this pressurizing means 4 is operated in the primary jet setting, a first pump 42 driven by a first motor 43 draws fluid (preferably water from the body of water surrounding the trenching device) through a first inlet 44. The first pump 42 pressurizes the fluid to substantially a first pressure P1 (the first pressure P1 plus losses between the first pump 42 and the multiple primary jet outlets) and supplies it to the multiple primary jet outlets along the first fluid outlet 45. In the primary jet setting, the second pump 47 is stationary; that is, the second pump 47 is not driven by the second motor 48. Therefore, there is no flow along the second fluid passage, or it is negligible.

[0109] When the trenching device using the first embodiment of the pressurizing means 4 is operated in a secondary jet setting, a second pump 47 driven by a second motor 48 draws fluid (preferably water from the body of water surrounding the trenching device) through a second inlet 49. The second pump 47 pressurizes the fluid to substantially a second pressure P2 (the second pressure P2 plus losses between the second pump 47 and the secondary jet outlet) and supplies it to the secondary jet outlet along the second fluid outlet 410. In the secondary jet setting, the first pump 42 may continue to operate to continue supplying fluid to the multiple primary jet outlets, or it may be kept stopped. In this case, the fluid flow along the first fluid passage is absent or negligible.

[0110] This first embodiment of the pressurizing means 4 can be used in any embodiment of the trenching apparatus described above.

[0111] Referring to Figure 8, a second embodiment of the pressurizing means 5 is shown. This pressurizing means 5 is similar to the pressurizing means 4 of the previous embodiment, and similar components are indicated by numbers beginning with "5" instead of "4". The difference between this pressurizing means 5 and the pressurizing means 4 of the previous embodiment is that the second fluid inlet 59 is connected to the first fluid outlet 55.

[0112] When the trenching apparatus equipped with the pressurizing means 5 of this embodiment is operated in the secondary jet setting, the first pump 52 pressurizes the fluid to a first pressure P1. This pressurized fluid flows along the first outlet 55 to a plurality of primary jet outlets and along the second inlet 59 to the second pump 57. In this way, the first pump 52 acts as a primer for the second pump 57. The second pump 57 then pressurizes the fluid substantially to a second pressure P2 and supplies it to the secondary jet outlet.

[0113] Similar to the previous embodiment, when the trenching device equipped with the pressurizing means 5 of this embodiment is operated in the primary jet setting, the second pump 57 remains stationary, and therefore no fluid or very little fluid flows along the second fluid passage.

[0114] This second embodiment of the pressurizing means 5 can be used in any embodiment of the trenching apparatus described above.

[0115] Referring to Figure 9, a third embodiment of the pressurizing means 6 is shown. This pressurizing means 6 is similar to the pressurizing means 5 of the previous embodiment, and similar components are indicated by numbers beginning with "6" instead of "5". The difference between this pressurizing means 6 and the pressurizing means 5 of the previous embodiment is that a first valve 611 is located at the first fluid outlet 65 and a second valve 612 is located at the second fluid inlet 69. The second fluid inlet 69 is connected to the first fluid outlet 65 at a position between the first pump 62 and the first valve 611. In this embodiment, the first valve 611 and the second valve 612 are solenoid valves that can be set to an open position that allows the passage of fluid and a closed position that prevents the passage of fluid.

[0116] When the trenching device equipped with the pressurizing means 6 of this embodiment is operated in the primary jet setting, the first valve 611 is open and the second valve 612 is closed. This prevents fluid from the first pump 62 from flowing along the second inlet 69. As in the previous embodiment, the second pump 67 is stationary. However, the second valve 612 eliminates the need for the second pump 67 to withstand the inlet pressure at the first pressure P1 generated by the first pump 62, as in the case of the pressurizing means 5 of the previous embodiment.

[0117] When the trenching device equipped with the pressurizing means 6 of this embodiment is operated in the secondary jet setting, the second valve 612 is open, and the first valve 611 is either left open to supply fluid to multiple primary jet outlets, or it is closed to supply all the fluid from the first pump 62 to the second pump 67.

[0118] This third embodiment of the pressurizing means 6 can be used in any embodiment of the trenching apparatus described above.

[0119] Referring to Figure 10, a fourth embodiment of the pressurizing means 7 is shown. This pressurizing means 7 is similar to the pressurizing means 6 of the previous embodiment, and similar components are indicated by numbers beginning with "7" instead of "6". The difference between this pressurizing means 7 and the pressurizing means 6 of the previous embodiment is that the second fluid pressurizing means 76 comprises a fluid intensifier 77 instead of a pump. The fluid intensifier 77 receives fluid at a first pressure P1 and a first flow rate and outputs fluid at a second pressure and a second flow rate lower than the first flow rate. The fluid intensifier 77 is driven by a turbine 78. A second inlet 79 is connected to the first fluid outlet 75 via a second valve 712, as in the embodiment of Figure 9. The second inlet 79 provides a fluid inlet to the fluid intensifier 77. The second inlet 79 also provides fluid for driving the turbine 78. The turbine 78 then mechanically drives the fluid intensifier. Similar to the second pump 67 in the previous embodiment, the fluid intensifier 77 pressurizes the fluid to a second pressure P2 and discharges it from the second outlet 710. The turbine 78 has a turbine outlet 713, which is optionally connected to an energy recovery system to reduce losses associated with high-speed discharge. In this embodiment, the flow is slowed down by a diffuser (a widening conical portion).

[0120] When the trenching device equipped with the pressurizing means 7 of this embodiment is operated in the primary jet setting, the first valve 711 is open and the second valve 712 is closed. This prevents fluid from the first pump 72 from flowing through the second inlet 79. In other words, the turbine 78 does not receive any driving force and the fluid intensifier 77 does not operate.

[0121] When the trenching device equipped with the pressurizing means 7 of this embodiment is operated in the secondary jet setting, the second valve 712 is open, and the first valve 711 is left open or closed. When left open, fluid is also supplied to multiple primary jet outlets. When closed, all fluid from the first pump 72 is supplied to the fluid intensifier 77 and turbine 78, driving the fluid intensifier 77. The fluid flowing through the turbine 78 passes through the turbine outlet 713 and is discharged, for example, by returning it to the water body, or sent to an energy recovery system.

[0122] This fourth embodiment of the pressurizing means 7 can be used in any embodiment of the trenching apparatus described above.

[0123] Referring to Figure 11, a fifth embodiment of the pressurizing means 8 is shown. In this embodiment, there is only one pressurizing means 81, which is the same as the first fluid pressurizing means 41 in Figure 7. Similar functions are indicated by numbers beginning with "8" instead of "4". In this embodiment, fluid is supplied from the pump 82 to multiple primary jet outlets and secondary jet outlets. A first valve 811 is provided between the multiple primary jet outlets and the pump 82, and a second valve 812 is provided between the secondary jet outlets and the pump 82.

[0124] When the trenching device equipped with the pressurizing means 8 of this embodiment is operated at the primary jet setting, the second valve 812 is closed. As a result, fluid is supplied only to the multiple primary jet outlets, and the pump 82 operates at substantially the first pressure P1.

[0125] When the trenching device equipped with the pressurizing means 8 of this embodiment is operated in the secondary jet setting, the second valve 812 opens, the first valve 811 closes, and the pump 82 outputs at substantially the second pressure P2, supplying fluid to the secondary jet outlet.

[0126] In all of the embodiments of the pressurizing means shown in Figures 9 to 13, the first fluid pressurizing means is shown to consist of one pump, but the number of pumps is arbitrary. For example, multiple pumps can be connected in series, or each pump can supply fluid to any number of primary jet outlets. Furthermore, in Figures 9 to 12, the second fluid pressurizing means is shown to consist of one pump or fluid intensifier, but any number of pumps or fluid intensifiers can be provided.

[0127] In another embodiment of the present invention, the jet arm as described in Figures 1 to 5 is provided with mounting means for attaching the jet arm to a trench cutting vehicle. A conduit extending along the jet arm has a conduit connector at its first end and is connected to a pressurizing means (one of the aforementioned pressurizing means) of the trenching device. This makes the jet arm retrofittable to the trenching device.

[0128] Those skilled in the art will understand that the features of the embodiments described can be combined. Furthermore, those skilled in the art will understand that any combination of the features described herein and / or the features shown in the accompanying drawings provides a clear advantage over the prior art and therefore falls within the scope of the invention described herein.

Claims

1. The main unit and One or more fluid pressurizing means, A trench-forming jet tool extending from the main body and including one or more primary jet outlets along its length, A first fluid passage extending between at least one of the one or more fluid pressurizing means and the one or more primary jet outlets, A jet arm, one end of which is connected to the main body, and which has one or more secondary jet outlets, A trenching device comprising at least one of the one or more fluid pressurizing means and a second fluid passage extending between the one or more secondary jet outlets, The trenching apparatus includes a primary jet setting that is operable to inject fluid from one or more primary jet outlets at a first pressure to cut or fluidize material adjacent to the trench-forming jet tool and form a trench, A trenching apparatus comprising a secondary jet setting that is operable to inject a fluid from one or more secondary jet outlets at a second pressure higher than the first pressure, thereby cutting or fluidizing material adjacent to the secondary jet outlets.

2. The trenching device according to claim 1, wherein the trenching device is operable with the secondary jet setting independently of the primary jet setting.

3. The controller is equipped with a controller, When the trenching device is operating with the primary jet setting, a parameter indicating the speed at which the trench is formed by the trench-forming jet tool is determined. Determine whether the aforementioned parameter is below the speed threshold. The trenching device according to claim 1 or 2, wherein if the parameter is below the speed threshold, the trenching device is configured to output a notification or instruction to operate with the secondary jet setting.

4. The trenching apparatus according to claim 3, wherein the parameter is the rate at which the trench is formed, for example, the length of the trench formed per unit time.

5. The aforementioned controller further, When the trenching device is operating with the secondary jet setting, a second parameter is determined that indicates the rate at which the material is cut or fluidized by one or more secondary jet outlets. Determine whether the second parameter is greater than or equal to the second velocity threshold. The trenching device according to claim 3 or 4, wherein the trenching device is configured to output a notification or instruction to operate with the primary jet setting when the second parameter is greater than or equal to the second speed threshold.

6. The trenching apparatus according to claim 5, wherein the second parameter is the rate at which the material is cut or fluidized by injecting fluid from one or more secondary jet outlets, for example, the volume of material cut or fluidized per unit time by injecting fluid from one or more secondary jet outlets.

7. The one or more fluid pressurizing means comprises a first fluid pressurizing means and a second fluid pressurizing means, The first fluid passage extends between the first fluid pressurizing means and the one or more primary jet outlets, The trenching apparatus according to any one of claims 1 to 6, wherein the second fluid passage extends between the second fluid pressurizing means and the one or more secondary jet outlets.

8. The trenching apparatus according to claim 7, wherein the second fluid passage extends between the first fluid pressurizing means and the second fluid pressurizing means, so that when the trenching apparatus is operated in the secondary jet setting, the fluid flows from the first fluid pressurizing means to the second fluid pressurizing means along the second fluid passage, and then flows from the second fluid pressurizing means to one or more secondary jet outlets along the second fluid passage.

9. The trenching apparatus according to claim 8, wherein the first fluid pressurizing means is a first pump, and the second fluid pressurizing means is a second pump or a fluid intensifier.

10. A trenching device according to any one of claims 1 to 9, comprising at least one valve located in the second fluid passage, wherein when the trenching device is operated in the primary jet setting, the at least one valve blocks the flow of fluid along the second fluid passage.

11. A trenching device according to any one of claims 1 to 10, comprising at least one valve located in the first fluid passage, wherein when the trenching device is operated in the secondary jet setting, the at least one valve blocks the flow of fluid along the first fluid passage.

12. The trenching apparatus according to any one of claims 1 to 11, wherein the trench-forming jet tool extends from the body at a first position of the body, and the jet arm is connected to the body at a second position other than the first position.

13. The trenching device according to claim 12, wherein the second position is located in front of the trenching device when in use.

14. The trenching device according to any one of claims 1 to 13, wherein the jet arm is movable between a stowed state and an operating state, and the jet arm is in the operating state when operating with the secondary jet setting.

15. The trenching device according to any one of claims 1 to 14, wherein the jet arm is an articulated arm.

16. The trenching apparatus according to any one of claims 1 to 15, wherein the jet arm comprises a plurality of arm portions connected by rotatable joints, one end of each arm portion being attached to the main body, and the jet arm comprises actuators associated with each rotatable joint, each actuator being configured to operate to rotate at least one of the arm portions attached to the corresponding rotatable joint around the corresponding rotatable joint.

17. The trenching device according to claim 16, wherein the jet arm is movable between a stowed state and an operating state, and in the stowed state the arm portions are stacked and substantially parallel to each other.

18. The trenching device according to claim 16 or 17, wherein at least one of the one or more secondary jet outlets is attached to the arm portion furthest from the arm portion attached to the main body.

19. The trenching device according to any one of claims 1 to 18, wherein the jet arm is rotatably mounted to the main body, and the trenching device comprises an actuator connected between the jet arm and the main body, the actuator being configured to move the jet arm relative to the main body.

20. A trenching apparatus according to any one of claims 1 to 19, wherein the first pressure is 4 to 16 bar and the second pressure is 12 to 120 bar.

21. A method for forming a trench underwater or on the seabed, A step of installing a trenching device at the bottom where the trench is to be formed, The trenching apparatus is operated in a primary jet setting in which material adjacent to a trench-forming jet tool extending from the body of the trenching apparatus to the bottom and forming the trench is cut or fluidized, and the cutting or fluidization of the material adjacent to the trench-forming jet tool is performed by injecting a fluid at a first pressure from one or more primary jet outlets arranged along the length of the trench-forming jet tool. A method comprising the steps of operating the trenching apparatus in a secondary jet setting such that material adjacent to one or more secondary jet outlets of the jet arm of the trenching apparatus is cut or fluidized, wherein one end of the jet arm is connected to the body of the trenching apparatus, and the cutting or fluidization of the material adjacent to the one or more secondary jet outlets is performed by injecting a fluid from the one or more secondary jet outlets at a second pressure higher than a first pressure.

22. The process of determining a parameter indicating the speed at which the trench is formed by the trench-forming jet tool when operating with the primary jet setting, A step of determining whether the aforementioned parameter is below a speed threshold, If the parameter is greater than or equal to the speed threshold, the trenching device is operated with the primary jet setting, The method according to claim 21, further comprising the step of operating the trenching device with the secondary jet setting if the parameter is below the speed threshold.

23. The method according to claim 22, wherein the parameter is the rate at which the trench is formed, for example, the length of the trench formed per unit time.

24. The steps include determining a second parameter that indicates the rate at which the material is cut or fluidized by one or more secondary jet outlets when operating with the aforementioned secondary jet settings, A step of determining whether the second parameter exceeds a second speed threshold, If the second parameter is below the second speed threshold, the trenching device is kept running with the secondary jet setting; The method according to claim 22 or 23, further comprising the step of operating the trenching device with the primary jet setting when the second parameter is greater than or equal to the second speed threshold.

25. The method according to claim 24, wherein the second parameter is the rate at which the material is cut or fluidized by injecting fluid from one or more secondary jet outlets, for example, the volume of material cut or fluidized per unit time by injecting fluid from one or more secondary jet outlets.

26. The method according to any one of claims 18 to 22, wherein the trenching device operates with the secondary jet setting independently of the primary jet setting.

27. The method according to any one of claims 21 to 26, wherein the step of injecting fluid from one or more primary jet outlets is performed by moving the fluid along a first fluid flow path extending between the first fluid pressurizing means and the primary jet outlet using a first fluid pressurizing means, and the step of injecting fluid from one or more secondary jet outlets is performed by moving the fluid along a second fluid flow path extending between the second fluid pressurizing means and the one or more secondary jet outlets using a second fluid pressurizing means.

28. The method according to claim 27, wherein the second fluid passage extends between the first fluid pressurizing means and the second fluid pressurizing means, and the step of injecting fluid from the secondary jet outlet is performed by moving the fluid from the first fluid pressurizing means to the second fluid pressurizing means along the second fluid passage, and then moving the fluid from the second fluid pressurizing means to one or more secondary jet outlets along the second fluid passage.

29. The method according to any one of claims 21 to 28, wherein when a fluid is injected from one or more primary jet outlets, the fluid is prevented from flowing along the second fluid passage to one or more secondary jet outlets by closing at least one valve located in the second fluid passage.

30. The method according to any one of claims 21 to 29, wherein when a fluid is injected from one or more secondary jet outlets, the fluid is prevented from flowing along the first fluid passage to one or more primary jet outlets by closing at least one valve located in the first fluid passage.

31. The method according to any one of claims 21 to 30, wherein when the trenching device is operated with the secondary jet setting, one or more secondary jet outlets are moved relative to the body of the trenching device to position the one or more secondary jet outlets adjacent to the material to be cut or fluidized.

32. The method according to any one of claims 21 to 31, wherein when the trenching device switches from operation to operation of the primary jet setting to operation of the secondary jet setting, the jet arm is moved from a retracted state to an operational state, and in this operational state, one or more secondary jet outlets are positioned adjacent to the material to be cut or fluidized.

Images