Key information

Title
Automatic pressure controlled cylinder
Application number
20180087
Case type
National
Status
31.01.2025 Ikke betalt årsavgift
Filed
19.01.2018
Effective date
19.01.2018
Publicly available
22.07.2019
Applicant
FossTech AS (NO)
Owner
FossTech AS (NO)
Inventor
Jo Myroldhaug (NO)
Agent
BRYN AARFLOT AS (NO)
Granted
09.09.2019
Patent number
344109

Abstract and drawing

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content.
The present invention is to provide an automatic pressure controlled circuit that is capable of controlling and executing an action of an actuator depending on changes in pressure of the surroundings. The hydraulic circuit comprises a port that is in pressure communication with the surroundings and a hydraulic actuator having a first chamber and a second chamber, said chambers being in communication with the port through valves. The actuator contains no electronics and battery and will operate exclusively on certain pressure conditions. The hydraulic circuit should reset itself after a sequence of actions have been completed.

Publications

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Documents

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Date
 Date Doc. No. Process Case number In/Out Journal description To/from
 15.08.2025 10-01 Saksbehandling 20180087(344109) UT PT Opphørt Patent - for ikke betalt årsavgift (3311) BRYN AARFLOT AS
 02.06.2025 09-01 Saksbehandling 20180087(344109) UT PT Påminnelse om ikke betalt årsavgift (3329) (PT20180087) BRYN AARFLOT AS
 03.12.2019 08-01 Saksbehandling 20180087 UT PT Varsel om betaling av første årsavgift (3317) (PT20180087)
11.09.2019 07-01 Saksbehandling 20180087 UT PT Registreringsbrev Nasjonal Patent (15) (PT20180087)
19.06.2019 06-01 Saksbehandling 20180087 UT Intention to grant PROTECTOR IP AS
 19.02.2019 05-05 Saksbehandling 20180087 INN Beskrivelse PROTECTOR IP AS
 19.02.2019 05-04 Saksbehandling 20180087 INN Beskrivelse med sporing PROTECTOR IP AS
 19.02.2019 05-03 Saksbehandling 20180087 INN Hovedbrev PROTECTOR IP AS
 19.02.2019 05-02 Saksbehandling 20180087 INN Krav PROTECTOR IP AS
 19.02.2019 05-01 Saksbehandling 20180087 INN Korrespondanse (Hovedbrev inn) PROTECTOR IP AS
 19.08.2018 04-02 Saksbehandling 20180087 UT PT report 12:13:05
19.08.2018 04-01 Saksbehandling 20180087 UT Realitet patent PROTECTOR IP AS
 23.01.2018 02-01 Saksbehandling 20180087 UT Infobrev til oppfinner Protector Intellectual Property Consultants AS
 19.01.2018 03-01 Saksbehandling 20180087 INN Korrespondanse (Hovedbrev inn) Protector Intellectual Property Consultants AS
 19.01.2018 01-06 Saksbehandling 20180087 INN Erklæring Søkers rett til oppfinnelse Protector Intellectual Property Consultants AS
 19.01.2018 01-05 Saksbehandling 20180087 INN Beskrivelse Protector Intellectual Property Consultants AS
 19.01.2018 01-04 Saksbehandling 20180087 INN Patenttegninger Protector Intellectual Property Consultants AS
 19.01.2018 01-03 Saksbehandling 20180087 INN Sammendrag Protector Intellectual Property Consultants AS
 19.01.2018 01-02 Saksbehandling 20180087 INN Fullmakt Protector Intellectual Property Consultants AS
 19.01.2018 01-01 Saksbehandling 20180087 INN Søknadsskjema Patent Protector Intellectual Property Consultants AS

Description, claims and drawings

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content. Description
3441091AUTOMATIC PRESSURE CONTROLLED CYLINDERTechnical Field[0001] The present invention relates to an automatic pressure controlled circuit for a hydraulic actuator.[0002] The invention is for example suitable for use in an actuator that is intended to actuate in certain pressure conditions, such as open a valve or a claw after the actuator first has been lowered to or below a certain water depth and then is subsequently brought to a lesser water depth.[0003] Such an actuator can be applied in marine industry applications, naval defense, seismic, subsea oil and gas, fishery and fish farming. In fisheries such an actuator is particularly useful for trawls and other nets, such as Danish seine, where there is a desire to expand the volume of the net as it is lifted to the surface. The actuator operates a claw or gripper that holds a part of the net during fishing. When the net is lifted up towards the surface and before the net is lifted onto the boat, the net is expanded by releasing the claw. Thereby the volume of the net is increased. Due to the increased volume, damage to the fish caused by squeezing will be reduced, with improved quality of the catch as a result, together with increased survival rate in case the fish caught will be used in fish farming. Increasing the volume of the net will also reduce the risk for rupturing the net by large catches.[0004] The actuator may also be used for any other purposes where an automatic action is desired when an object is lifted from a deeper water depth to a shallower water depth.Background Art[0005] There are known devices that can perform such task, albeit they require some form of intervention to reset the device after execution.[0006] One such device is described in WO 9820257. It describes an inverted accumulator for underwater use comprises an air-filled low-pressure chamber which is lowered down to the seabed. The chamber is connected to a piston/cylinder device. The pressure difference will be capable of activating a piston stroke which is used to perform a task, such as opening or closing a valve.[0007] The device can perform a once-only operation. In order to repeat the execution, the device must be reset by turning a valve. If this resetting is omitted, the device will not work.[0008] US 4514924 describes a device for closing the mouth opening of a net prior to bringing the fishing net back aboard the fishing vessel. The device comprises a hose that is pressurized and a dump valve to depressurize the hose. A pump is used to pressurize the hose.[0009] This device is manually actuated, and its actuation is not related to water depths.[0010] WO9219836 describes a machine for performing work at great depths, which utilizes the energy which is released when surrounding water masses at great hydrostatic pressure are admitted into a low-pressure reservoir via a hydraulic motor. The machine uses a built-in low-pressure reservoir as a hydrostatic accumulator, the energy which is released when the surrounding fluid is admitted into the low-pressure reservoir being determined by the product of the pressure difference and the internal volume of the low-pressure reservoir. In a special version the machine is designed as a hydrostatic sampler which is particularly adapted for taking core samples or marine sediments on the seabed.[0011] This device also performs a one-time-only operation. Before the next use, the device must be reset. The resetting procedure is not explained in the publication.[0012] US2010155071 describes a water submerged device for generating a force under water. The device includes a low-pressure recipient configured to contain a volume of a first fluid at a low-pressure volume, an inlet connected to the lowpressure recipient and configured to exchange a second fluid with an external enclosure, and a valve connected to the external enclosure and the inlet and configured to separate a pressure source in the external enclosure from the lowpressure recipient. When the valve is open, such that there is a flow communication between the external enclosure and the low-pressure recipient, a pressure imbalance occurs in the external enclosure which generates the force and the second fluid from the external enclosure enters the low-pressure recipient and compresses the first fluid.[0013] This device is only operable through the operation of the valve, and it is therefore not operating automatically.[0014] US 3436914 describes a hydrostatic energy accumulator where a valve is selectively opened at a specific depth to cause a pressure differential, which releases energy for performing underwater work.[0015] As the valve has to be operated to release the energy, the known device cannot operate automatically.[0016] US 3195261 describes a device that opens an escape opening at the cod end of a fishing net. The opening is effected by the pressure exerted from excess of fish.[0017] US 2015/0308212 describes a pressure-controlled circuit in pressure communication with the surroundings. The circuit must be manually reset to be ready for another operation.[0018] The same is also true for US 8726644, GB 2291510 and WO 2016/171664.[0019] None of the prior art devices are capable of effecting the triggering of the actuator automatically, i.e. by pressure differential alone, when the device is brought from a deeper water depth to a shallower water depth and automatic resetting of the device.Summary of invention[0020] The aim of the present invention is to provide an automatic pressurecontrolled circuit that is capable of controlling and executing an action of an actuator depending on changes in pressure of the surroundings. The hydraulic circuit comprises a port that is in pressure communication with the surroundings and a hydraulic actuator having a first chamber and a second chamber, said chambers being in communication with the port through valves. The actuator contains no electronics and battery and will operate exclusively on certain pressure conditions. The hydraulic circuit should reset itself after a sequence of actions have been completed. [0021] The above objectives are fulfilled by a hydraulic circuit where said first chamber is in communication with the port through a first sequence valve and said second chamber being in communication through a second sequence valve, said first sequence valve being configured to close the communication between the port and said first chamber when the pressure at the port exceeds a first threshold pressure and open said communication when the pressure at the port falls below said first threshold pressure, said second sequence valve being configured to close the communication between the port and the second chamber when the pressure at the port exceeds a second threshold pressure and open said communication when the pressure at the port falls below said second threshold pressure, said second threshold pressure being higher than said first threshold pressure, said first chamber also being in communication with the port through a first check valve, said first check valve being configured to block flow from the first chamber towards the port, and said second chamber being in communication with the port through a second check valve, said second check valve being configured to block flow from the second chamber towards the port.[0022] In a preferred embodiment, said actuator is biased against the pressure of said first chamber. This ensures that the actuator will be kept in a first position throughout the first phase of change in the pressure of the surroundings.[0023] In a further embodiment, said actuator is a hydraulic cylinder having a piston separating said first and said second chambers. This is a convenient actuator for performing actions based on a linear stroke.[0024] In an alternative embodiment, said actuator is a rotary actuator. This is a convenient type of actuator for performing actions based on rotation.[0025] Preferably, said first and second sequence valves are biased towards the open position. This provides a convenient embodiment for performing an action based on an initially increased pressure of the surroundings.[0026] In a preferred embodiment, the sequence valves are biased by a respective adjustable spring. This provides a simple and easy way of adjusting the threshold pressures for closing the sequence valves. [0027] In an alternative or supplemental embodiment, the sequence valves are biased by a pressurable accumulator. This provides further possibilities for adjusting the threshold pressures of the sequence valves within a wide range.[0028] In a further detailed embodiment, the sequence valves are biased by a separate pressurable accumulators. This provides a further possibility to adjust the threshold pressures of the sequence valves individually.[0029] In a further preferred embodiment, the first and second check valves are biased towards the closed position. This ensures proper closing of the check valves when the pressure of the surroundings have increased the maximum pressure and starts to decrease.[0030] In a further preferred embodiment, the first chamber is in communication with a pressure accumulator. This ensures a constant pressure in the first chamber when the actuator operates.[0031] In a practical use of the hydraulic circuit of the invention, said actuator operates a claw to open or close said claw depending on the pressure difference between said first and second chambers.Brief description of drawings[0032]Figure 1 shows the hydraulic circuit of the invention in an initial stage,Figure 2 shows the hydraulic circuit of the invention while the surrounding pressure increases in a first phase,Figure 3 shows the hydraulic circuit of the invention after the pressure of the surroundings has exceeded the first threshold pressure,Figure 4 shows the hydraulic circuit of the invention after the pressure of the surroundings has exceeded the second threshold pressure,Figure 5 shows the hydraulic circuit of the invention when the pressure of the surroundings has reached the maximum pressure,Figure 6 shows the hydraulic circuit of the invention after the pressure of the surroundings has fallen below the second threshold pressure,Figure 7 shows the hydraulic circuit of the invention after the pressure of the surroundings has fallen below the second threshold pressure and the actuator has been actuated,Figure 8 shows the hydraulic circuit of the invention after the pressure of the surroundings has fallen below the first threshold pressure,Figure 9 shows the hydraulic circuit of the invention when the pressure of the circuit has been allowed equalize with the surroundings, andFigure 10 shows pressure curves for an exemplary roundtrip from atmospheric pressure to an elevated pressure and back to atmospheric pressure.Detailed description of the invention[0033] Figure 1 shows a hydraulic control circuit of the present invention in a first state.[0034] Before explaining the functioning of the hydraulic circuit, the various components will be explained.[0035] The hydraulic circuit has a pressure port 1, which is open to the environment and communicates the pressure of the environment into the circuit.[0036] The pressure port 1 is in direct communication with a first sequence valve 2, a second sequence valve 3, a first check valve 4 and a second check valve 5.[0037] The sequence valves 2, 3 have a respective pilot line 22, 23, which both are sensing the pressure of the pressure port 1. [0038] Each sequence valve 2, 3 also has a biasing spring 13, 14, which biases the valve 2, 3 towards the open position. The springs 13, 14 may be adjustable or have a preset biasing force.[0039] The sequence valves 2, 3 also has each a drain line 24, 25. The drain lines are both in communication with a first common accumulator 7. The first accumulator 7 is pressurized with a first pressure P1. The pressure P1 is determined by the intended operational depth of the actuator. It is however also conceivable that the drain lines 24, 25 are in communication with two separate accumulators.[0040] At the opposite side of the first sequence valve 2 and the first check valve 4, the valves 2, 4 are in communication with a second accumulator 6. The valves 2, 4 are also at the same side in communication with a first side 12, e.g., the head end, of a hydraulic cylinder 8.[0041] The check valve 4 allows a flow in a direction from the pressure port 1 and into the hydraulic cylinder 8 head end 12, but prevents flow in the opposite direction. The check valve 4 has a spring 26, which biases the check valve 4 towards the closed position. Hence, a certain pressure is necessary at the pressure port 1 to open the check valve 4.[0042] The second sequence valve 3 and the second check valve 5 are both at the opposite side relative to the pressure port 1, in communication with the hydraulic cylinder 8 at a second side 10, e.g., the rod end 10 of the cylinder.[0043] The check valve 5 allows a flow in a direction from the pressure port 1 and into the hydraulic cylinder 8 rod end 10, but prevents flow in the opposite direction. The check valve 5 has a spring 27, which biases the check valve 5 towards the closed position. Hence, a certain pressure is necessary at the pressure port 1 to open the check valve 5.[0044] The cylinder 8 has a piston 28 to which a rod 11 is attached. The piston divides the cylinder into a head chamber at the head end 12 and a rod chamber at the rod end 10.[0045] A spring 9 is arranged within the rod chamber 10 and biases the piston towards the head end 12. The spring may also be arranged external of the cylinder. [0046] The function of the hydraulic circuit will now be explained referring to figures 1 – 9, showing the hydraulic circuit in different states and figure 10, which shows pressure curves for an exemplary roundtrip from atmospheric pressure to an elevated pressure and back to atmospheric pressure. Atmospheric pressure is here set to zero and the pressure above atmospheric pressure in bar is given along the Y-axis. The X-axis denoted the time passed from the start to the end of the cycle. The cycle may be a haul of a fishing gear, such as a trawl or Danish seine, from the moment the fishing gear is shot until it is again brought onboard.[0047] A curve PS shows the pressure of the surroundings, a curve P1 shows the pressure of the first accumulator 7, a curve P2 shows the pressure of the second accumulator 6, and points PT1, PMAX and PT2 show certain pressures that will be explained further below.[0048] Figure 1 shows the hydraulic circuit in a state where the pressure Ps of the surroundings acting on the pressure port 1, is low and below a first threshold pressure PT1. At the pressure PT1 the first sequence valve 2 is set to close. The surrounding pressure may in this state be atmospheric pressure. We are now at the beginning of the pressure curves of figure 1, i.e. at the very left. The Pressure P1 of the first accumulator 7 is in this example slightly above atmospheric pressure, and the pressure P2 of the second accumulator 6 is set to about 4 bar.[0049] In this state the sequence valves 2, 3 are open, as the biasing force of the springs 13, 14 is greater than the force acting from the surrounding pressure PS and will thus hold the sequence valve in the open position. The check valves 4, 5 are closed, as the biasing springs 26, 27 exert a force that overcomes the surrounding pressure PS. Since the surrounding pressure PS is communicated through the sequence valves 2, 3 to both sides of the piston 28, the piston 28 is maintained in a position towards the head end 12 due to the biasing spring 9.[0050] The second accumulator 6 is initially charged with a pressure P2, such as 4 atm. When the pressure of the surroundings exceeds 4 atm., this means that the pressure of the second accumulator 6 will be at the same pressure as the surrounding pressure PS as the surrounding pressure PS is communicated through the first sequence valve 2. [0051] Figure 2 shows the state when the surrounding pressure PS has increased somewhat. The surrounding pressure PS is now sufficient to open the check valves 4, 5 against the springs 26, 27. Since both check valves 4, 5 (and both sequence valves 2, 3) are open, the pressure will increase equally in both chambers of the cylinder 8.[0052] In figure 3, the surrounding pressure PS has increased beyond the first threshold pressure PT1 at which the first sequence valve 2 closes. At this pressure the surrounding pressure overcomes the combined force from the spring 13 and the pressure P1 from the first accumulator 7. This will result in a slight increase of the pressure P1 of the first accumulator 7, as shown by the curve of figure 10. However, the surrounding pressure PS will still be communicated to the head end 12 of the cylinder 8 through the first check valve 4. The sequence valve 3 and the check valve 5 remains open and communicates the surrounding pressure PS to the rod end 10 of the cylinder 8.[0053] When the surrounding pressure PS increases above the pressure P2 of the second accumulator 6, the pressure P2 in the second accumulator 6 will increase with the pressure PS, as shown in figure 10.[0054] In figure 4 the surrounding pressure PS has reached a second threshold pressure PT2, which is the pressure at which the second sequence valve 3 closes. At this pressure the surrounding pressure overcomes the combined force from the spring 14 and the pressure P1 from the first accumulator 7. This results in another slight increase of the pressure P1 in the first accumulator 7, as shown in figure 10.[0055] However, the surrounding pressure PS will still be communicated through the second check valve 5. Hence the pressure will still be equal in both chambers of the cylinder 8. This will be the state of the hydraulic circuit during a further increase of the pressure PS of the surroundings. Consequently, there will be no further valve actions until the device containing the hydraulic circuit has reached its maximum depth.[0056] In figure 5, the maximum pressure of the surroundings has been reached. This may be due to the device containing the hydraulic circuit having been lowered below a desired depth at sea. Figure 5 shows the situation after the pressure in the hydraulic circuit, i.e. in both chambers 10, 12 of the cylinder 8 and the accumulator 6 has equalized with the surrounding pressure. At this stage the check valves 4, 5 are brought to the closed position by the springs 26, 27. The hydraulic pressure of the cylinder 8 chambers and the accumulator 6 is now isolated from the surroundings by the closed check valves 4, 5 and the closed sequence valves 2, 3. This pressure is denoted Pmax, as shown in figure 10.[0057] The pressure Pmax will be retained in the circuit until the surrounding pressure PS is lowered again, e.g., by bringing the device to a shallower depth, to the second threshold pressurePT2, as shown by the curve of PS in figure 10. When reaching this pressure PT2, the second sequence valve 3 will again open due to the force from the spring 14 and the pressure P1 of the first accumulator 7, as shown in figure 6. At the same time the pressure P1 will drop slightly due to the movement of the second sequence valve 3.[0058] When the second sequence valve 3 has opened, the rod chamber 10 of the cylinder 8 will be placed in communication with the surroundings. Hence the pressure of the rod chamber 10 will quickly equalize with the surroundings. In the head chamber 12, the pressure will still be at the higher pressure Pmax. Due to this the piston 28 will be forced towards the rod end of the cylinder 8 against the lower pressure PS and the force of the spring 9, as shown in figure 7. This movement of the piston 28, and the rod 11, which is coupled to the piston 28, will initiate the action that the device is intended for, e.g., opening a claw to release a part of the net and thereby expand the volume of the net. The movement of the piston 28, and consequent increase of the volume of the head chamber 12 of the cylinder 8, will result in a decrease of the pressure P2, as shown in figure 10 to a level somewhere between Pmax and PT2. The amount of pressure drop is depending on the ratio between the volumes of the second accumulator 6 and the cylinder 8.[0059] When the pressure of the surroundings is lowered further, such as by bringing the device to the surface, the pressure PS of the surroundings will be reduced further and below the first threshold PT1. At this pressure, the first sequence valve 2 will also open by the combined force of the spring 13 and the pressure P1 of the first accumulator 7, as shown in figure 8. This results in another slight drop in the pressure P1 of the first accumulator, as shown in figure 10.[0060] As soon as the first sequence valve 2 has opened, the head chamber 12 of the cylinder 8 will be placed in communication with the surroundings via the first sequence valve 2. Hence, the pressure in the head chamber 12 will drop to the pressure of the surroundings. This results in a further drop of the pressure P2 of the second accumulator 6 to the initial pressure of the accumulator.[0061] With the pressure of the two chambers 10, 12 of the cylinder 8 now being equal, the piston 28 will be forced towards the head end by the spring 9, as shown in figure 9. The action made by the rod 11 is then reversed, e.g. the claw is closed again. At this stage, the circuit is back to the situation shown in figure 1, and the hydraulic circuit is ready to repeat the same procedure as explained above.[0062] Before the procedure is repeated, it might be necessary to bring the claw to grip the rope or part of the net, which it is supposed to hold when the net is brought over board to perform the fishing. The rod 11 is preferably not mechanically coupled to the claw, but adapted to push a release mechanism of the claw. Hence the claw can be forced mechanically open without any interference of the cylinder 8 and rod 11.[0063] The threshold pressures PT1 and PT2 at which the sequence valves 2 and 3, respectively closes, can be set individually by adjusting the springs 13 and 14.[0064] A suitable threshold pressures., e.g., for a claw to retain a part of a net during fishing, could be 0,5 bar above atmospheric pressure for the first sequence valve 2 and 1,5 bar above atmospheric pressure for the second sequence valve 3.[0065] The accumulator 7 provides a further opportunity for adjusting the threshold pressures. By pre-charging the accumulator 7 with a chosen pressure, the threshold pressures of the two sequence valves can be set.[0066] In addition to or as an alternative to the two biasing springs 13, 14, two separate accumulators can also be used; one accumulator connected to the first sequence valve 2 and one accumulator connected to the second sequence valve 3. By preloading the two accumulators with different pressures, the threshold pressures can be set.[0067] The second accumulator 6 serves to keep a constant pressure in the head chamber 12 of the cylinder 8. Without the second accumulator 6, the pressure in the head chamber would sink as the piston moves towards the rod end 10. This could result in the intended action not being executed fully. [0068] The cylinder could of course be configured to be biased in the opposite direction, so that the piston is forced towards the rod end by the spring.[0069] The cylinder may also have a rod at both sides of the piston so that it can perform to opposite actions when the piston is moved, such as opening one claw and closing another claw.[0070] Instead of a hydraulic cylinder, the actuator could be a hydraulic rotary motor.[0071] The port 1 may be fully open to the surroundings to allow water to flow into the hydraulic circuit and fill the chambers of the cylinder. However, it is more convenient to avoid water, such as sea water to enter the hydraulic circuit, as this contains debris and fouling agents, which potentially could be detrimental to the functioning of the components. Consequently, it is preferred to have a barrier between the circuit and the surroundings, which may transfer pressure but divide hydraulic fluid, such as oil, in the circuit from the water. Such a barrier may be a separating piston or a membrane of a well-known type that will transfer pressure relatively unhindered, but is fluid tight.[0072] Although, the device is meant to operate completely without any other power source than the pressure of the surroundings, and of course the pre-charging of the accumulators, it is conceivable to include sensors, such as pressure sensors in the hydraulic circuit. Then the operation of the device can be supervised.
Claims
Claims1. An automatic pressure controlled circuit, comprising a port (1) that is in pressure communication with the surroundings, and a hydraulic actuator (8) having a first chamber (12) and a second chamber (10), said chambers (12, 10) being in communication with the port (1) through valves (2, 3, 4, 5), said first chamber (12) being in communication with the port (1) through a first sequence valve (2) and said second chamber (10) being in communication with the port (1) through a second sequence valve (3), , wherein- said first sequence valve (2) being configured to close the communication between the port (1) and said first chamber (12) when the pressure (PS) at the port (1) exceeds a first threshold pressure (PT1) and open said communication when the pressure (PS) at the port (1) falls below said first threshold pressure (PT1),- said second sequence valve (3) being configured to close the communication between the port (1) and the second chamber (10) when the pressure (PS) at the port (1) exceeds a second threshold pressure (PT2) and open said communication when the pressure (PS) at the port (1) falls below said second threshold pressure (PT2),- said second threshold pressure (PT2) being higher than said first threshold pressure (PT1),- said first chamber (12) also being in communication with the port (1) through a first check valve (4), said first check valve (4) being configured to block flow from the first chamber (12) towards the port (1), and- said second chamber (10) being in communication with the port (1) through a second check valve (5), said second check (5) valve being configured to block flow from the second chamber (10) towards the port (1).2. The circuit of claim 1, wherein said actuator (8) is biased against the pressure of said first chamber (12).3. The circuit of claim 2, wherein said actuator (8) is a hydraulic cylinder having a piston (28) separating said first and said second chambers (12, 10).4. The circuit of claim 1 or 2, wherein said actuator (8) is a rotary actuator.5. The circuit of any of the preceding claims, wherein said first and second sequence valves (2, 3) are biased towards the open position.6. The circuit of claim 4, wherein the sequence valves (2, 3) are biased by a respective adjustable spring (13, 14).7. The circuit of claims 4 or 5, wherein the sequence valves (2, 3) are biased by a pressurable accumulator (7).8. The circuit of claims 4 or 5, wherein the sequence valves (2, 3) are biased by a separate pressurable accumulators.9. The circuit of any of the preceding claims, wherein the first and second check valves (4, 5) are biased towards the closed position.10. The circuit of any of the preceding claims, wherein the first chamber (12) is in communication with a pressure accumulator (6).11. The circuit of any of the preceding claims, wherein said actuator (8) operates a claw to open or close said claw depending on the pressure difference between said first and second chambers (12, 10).Patentkrav1. En automatisk trykkontrollert krets, omfattende en port (1) som er i trykkommunikasjon med omgivelsene og en hydraulisk aktuator (8) som har et første kammer (12) og et andre kammer (10), der kammerne (12, 10) er i kommunikasjon med porten (1) gjennom ventiler (2, 3, 4, 5), idet det første kammeret (12) er i kommunikasjon med porten gjennom en første sekvensventil (2) og det andre kammeret (10) er i kommunikasjon med porten (1) gjennom en andre sekvensventil (3), karakterisert ved at:- den første sekvensventilen (2) er konfigurert til å stenge kommunikasjonen mellom porten (1) og det første kammeret (12) når trykket (PS) i porten (1) overskrider et første terskeltrykk (PT1) og åpne kommunikasjonen når trykket (PS) i porten (1) faller under det første terskeltrykket (PT1),- den andre sekvensventilen (3) er konfigurert til å stenge kommunikasjonen mellom porten (1) og det andre kammeret (10) når trykket (PS) i porten (1) overskrider et andre terskeltrykk (PT2) og åpne kommunikasjonen når trykket (PS) i porten (1) faller under det andre terskeltrykket (PT2),- det andre terskeltrykket (PT2) er høyere enn det første terskeltrykket (PT1),- det første kammeret (12) også er i kommunikasjon med porten (1) gjennom en første tilbakeslagsventil (4), idet den første tilbakeslagsventilen er konfigurert til å blokkere strømning fra det første kammeret (12) mot porten (1), og- det andre kammeret (10) er i kommunikasjon med porten (1) gjennom en andre tilbakeslagsventil (5), idet den andre tilbakeslagsventilen (5) er konfigurert til å blokkere strømning fra det andre kammeret (10) mot porten (1).2. Kretsen ifølge krav 1, karakterisert ved at aktuatoren (8) er forspent mot trykket i det andre kammeret (12).3. Kretsen ifølge krav 2, karakterisert ved at aktuatoren (8) er en hydraulisk sylinder med et stempel (28) som skiller det første og det andre kammeret (12, 10).4. Kretsen ifølge krav 1 eller 2, karakterisert ved at aktuatoren (8) er en roterbar aktuator.5. Kretsen ifølge et hvilket som helst av de foregående krav, karakterisert ved at den første og den andre sekvensventilen (2, 3) er forspent mot åpen posisjon.6. Kretsen ifølge krav 4, karakterisert ved at sekvensventilene (2, 3) er forspent ved hjelp av en respektiv justerbar fjær (13, 14).7. Kretsen ifølge krav 4 eller 5, karakterisert ved at sekvensventilene (2, 3) er forspent av en trykksatt akkumulator (7).8. Kretsen ifølge krav 4 eller 5, karakterisert ved at sekvensventilene (2, 3) er forspent av separate trykksatte akkumulatorer.9. Kretsen ifølge et hvilket som helst av de foregående krav, karakterisert ved at den første og andre tilbakeslagsventilen er forspent mot lukket posisjon.10. Kretsen ifølge et hvilket som helst av de foregående krav, karakterisert ved at det første kammeret (12) er i kommunikasjon med en trykkakkumulator (6).11. Kretsen ifølge et hvilket som helst av de foregående krav, karakterisert ved at aktuatoren (8) opererer en klo for å åpne eller lukke kloen i avhengighet av trykkdifferansen mellom det første og det andre kammeret (12, 10).
Drawings

Priority

No priority

Patent classes

IPC classesE21B 33/035CPC classesE21B 33/035E21B 33/0355

Citations

US 2015/308212 A1 (A1)US 8726644 B2 (B2)GB 2291510 A (A)WO 2016/171664 A1 (A1)

Applicants, owners and inventors

Owners
FossTech AS
Borgeskogen 7 3160 STOKKE NO (SANDEFJORD Municipality, Vestfold county)Org. number: 886680422Inventors
Jo Myroldhaug
Borgeskogen 7 3160 STOKKE NO (SANDEFJORD Municipality, Vestfold county)

Agent

BRYN AARFLOT AS
BRYN AARFLOT AS

Org. number: 979993269

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Open in The Brønnøysund Register Centre
Stortingsgata 8 0161 OSLO NO (OSLO Municipality, Oslo county)
Org. number: 979993269
Reference: P5402NO00

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