PRESSURE CYCLING SYSTEMS AND RELATED METHOD

CROSS REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 USC § 119(e), this application claims the benefit of prior U.S. Provisional Application 60/914,926, filed April 30, 2007 and U.S. Provisional Application 60/886,817, filed January 26, 2007. Each of these applications is incorporated by reference in its entirety.

TECHNICAL FIELD

This disclosure relates to controlling pressure-sensitive reactions, and more particularly to systems and methods for controlling the timing of pressure- sensitive reactions.

BACKGROUND

Devices are known for providing control over timing and/or synchronization of pressure- sensitive reactions (e.g., chemical reactions). Such devices are known to include one or more pressure modulated reaction vessels and means for producing fluctuations in pressure in the reaction vessels. Samples can be deposited in the reaction vessels and exposed to changes in pressure to control one or more pressure-sensitive reactions within or between the samples.

SUMMARY

In general, this disclosure relates to pressure cycling systems and related methods. The systems can be used, for example, to provide a pressure modulated environment for controlling pressure-sensitive events (e.g., physical, kinetic, structural, morphological, thermodynamic, and/or chemical reactions, e.g., enzymatic and non-enzymatic reactions).

In one aspect, a pressure cycling system includes a reaction chamber configured to receive a sample and a charge pump in fluid communication with the reaction chamber. The charge pump is operable to convey a fluid from a fluid source toward the reaction chamber. The system also includes a check valve disposed between the charge pump and the reaction chamber. The check valve is operable to inhibit the flow of fluid from the reaction chamber toward the charge pump. A pressure intensifier is in fluid communication with the reaction chamber. The pressure intensifier is pneumatically operable to adjust a pressure in the reaction chamber. A controller is configured to

control operation of the charge pump and the pressure intensifier. The controller is configured to pressurize the reaction chamber to a first pressure through operation of the charge pump. The controller is also configured to fluctuate the pressure in the reaction chamber between a second pressure and a third pressure through operation of the pressure intensifier.

In another aspect, a method of controlling timing of pressure-sensitive reactions includes depositing a sample in a reaction chamber and pressurizing the reaction chamber to a first pressure. Pressurizing the reaction chamber includes conveying a fluid from a fluid source to the reaction chamber through a check valve. The method also includes cycling a pressure level in the reaction chamber between a second pressure and a third pressure. Cycling the pressure level includes driving a pressure intensifier with a pressurized gas.

Embodiments can include one or more of the following features.

In some embodiments, the third pressure is greater than the second pressure, and the second pressure is greater than or equal to the first pressure.

The controller is configured to control operation of the charge pump and the pressure intensifier based, at least in part, on user input.

In some implementations, a fluid pressure sensor is disposed between the charge pump and the check valve and in communication with the controller. The controller is configured to control operation of the charge pump and the pressure intensifier based, at least in part, on feedback from the fluid pressure sensor.

In some embodiments, the controller is configured to inhibit operation of the charge pump in response to receiving feedback from the fluid pressure sensor indicating that the reaction chamber is pressurized to the first pressure. In some implementations, the controller is configured to initiate operation of the pressure intensifier in response to receiving feedback from the fluid pressure sensor indicating that the reaction chamber is pressurized to the first pressure.

In some embodiments, the systems and/or methods can include a pressure regulator operable to control a flow of a pressurized gas from a pressurized gas source toward the pressure intensifier. The controller can be configured to control the operation of the pressure regulator based on a feedback from the fluid pressure sensor.

In some implementations, the controller is configured to control operation of the pressure regulator based, at least in part, on user input.

In some embodiments, a gas pressure sensor is disposed between the pressure regulator and the pressure intensifier, and configured to provide feedback to the controller. The controller can be configured to control operation of the pressure regulator based, at least in part, on the feedback from the gas pressure sensor. In some implementations, a directional control valve is disposed between the pressure regulator and the pressure intensifier and operable to control the flow of pressurized gas between the pressure regulator and the pressure intensifier.

In some embodiments, the controller can be configured to control operation of the directional control valve. In some implementations, the controller is configured to control operation of the directional control valve based, at least in part, on user input.

In some embodiments, a gas pressure sensor is disposed between the pressure regulator and the pressure intensifier. The gas pressure sensor can be configured to provide feedback to the controller. The controller can be configured to control operation of the directional control valve based, at least in part, on feedback from the gas pressure sensor.

In some implementations the directional control valve comprises a 4- way directional control valve.

In some embodiments, the pressure intensifier includes a pneumatic chamber, a fluid chamber arranged in fluid communication with the reaction chamber, and a piston disposed between the pneumatic chamber and the fluid chamber. The piston is displaceable to adjust a volume of the fluid chamber, and wherein the controller is configured to control displacement of the piston.

In some implementations a pressure regulator is operable to control a flow of a pressurized gas from a pressurized gas source toward the pneumatic chamber. The controller can be configured to control operation of the pressure regulator.

In some embodiments, the controller is configured to control fluid pressure in the reaction chamber through operation of the pressure regulator.

In some implementations, the controller is configured to control displacement of the piston through operation of the pressure regulator.

In some embodiments, a directional control valve is disposed between the pressure regulator and the pressure intensifier. The directional control valve is operable to control the flow of pressurized gas between the pressure regulator and the pneumatic chamber.

The controller can be configured to control operation of the directional control valve, and wherein the controller is configured to control displacement of the piston through operation of the pressure regulator and the directional control valve.

In some implementations, an end-of-stroke sensor is operable to detect the presence of the piston at an end-of-stroke position, corresponding to a minimum volume of the fluid chamber. The end-of-stroke sensor is configured to provide feedback to the controller. The controller can be configured to control operation of the charge pump and/or the pressure intensifier in response to receiving feedback from the end-of-stroke sensor indicating that the reaction chamber is at the end-of-stroke position. In some embodiments, the systems and/or methods can include a reaction vessel defining the reaction chamber. The reaction vessel can include an aperture extending from the reaction chamber to a first open end and sized to allow insertion of the sample into the reaction chamber. The systems or methods can also include a vessel cover releasably connectable to the reaction vessel and operable to form a substantially hermetic barrier between the reaction chamber and the first open end.

In some implementations, the vessel cover includes a vent actuator (e.g., a button) being operable to vent gases and/or fluids from the reaction chamber during use.

In some embodiments, the vessel cover includes a release valve being operable to inhibit the release of gases and/or fluids from the reaction chamber, and the vent button is engageable to open the release valve.

In some implementations, the vessel cover defines a flow pathway adapted to allow the release of gases and/or fluids from the reaction chamber through the vessel cover.

In some embodiments, the systems and/or methods can include a drain line in fluid communication with the flow pathway. The drain line can be disposed between the flow pathway and the fluid source. The drain line can be adapted to direct a flow of gases and/or fluids from the flow pathway toward the fluid source for recovery, or drain for disposal.

In some implementations, the flow pathway is adapted to direct a flow of gases and/or fluids from the reaction chamber toward a drain region of the aperture.

In some embodiments, the reaction vessel defines a drain conduit in fluid communication with the flow pathway and adapted to allow the release of gases and/or fluids from the flow pathway through the reaction vessel.

In some implementations, the systems or devices can include a drain line disposed between the drain conduit and the fluid source and adapted to direct a flow of gases and/or fluids from the flow pathway toward the fluid source, thereby providing for recovery of gases and/or fluids released from the reaction chamber. In some embodiments, a cover sensor is configured to communicate with the controller. The cover sensor is operable to detect a connection between the vent cover and the reaction vessel. The controller can be configured to inhibit pressurization of the reaction chamber in response to receiving feedback from the cover sensor indicating an open connection between the vent cover and the reaction vessel. In some implementations, the systems and/or methods can include a sample vessel defining a sample chamber configured to receive the sample, and including a plunger disposed between a first open end of the sample vessel and the sample chamber. The reaction chamber can be configured to receive the reaction vessel. The plunger is displaceable, in response to changes in pressure in the reaction chamber, to adjust a volume of the sample chamber, thereby to adjust a pressure exerted on the sample.

In some embodiments, the second pressure is between about 150 psi and about 35,000 psi.

In some implementations, the third pressure is between about 3,500 psi and about 35,000 psi. In some embodiments, the methods can include venting the reaction chamber of gases and/or fluids prior to pressurizing the reaction chamber to the first pressure.

In some implementation, the pressure intensifier includes a pneumatic chamber, a fluid chamber arranged in fluid communication with the reaction chamber, and a piston disposed between the pneumatic chamber and the fluid chamber. Cycling the pressure in the reaction chamber can include displacing the piston relative to the fluid chamber.

In some implementations, displacing the piston relative to the fluid chamber includes directing a flow of pressurized gas towards a first surface of the piston, to cause the piston to move in a first direction relative to the fluid chamber; and redirecting the flow of pressurized gas towards a second surface of the piston, opposite the first surface, to cause the piston to move in a second direction, opposite the first direction.

In some embodiments, the methods can include maintaining the reaction chamber at a temperature of between about -40 ⁰ C and about 100 ⁰ C.

Embodiments can include one or more of the following advantages.

In some embodiments, the systems provide for relatively small and light weight pressure cycling.

In some implements, the systems and methods provide for portable pressure cycling. In some embodiments, the systems and methods provide for time, pressure and/or temperature regulated control of pressure sensitive reactions.

In some implementations, the systems and methods can be used to conduct reactions including one or more pressure- sensitive steps. These reactions can include, for example, anti-body binding, DNA binding, lysis, activation (germination), inactivation, structural modification, permeation/diffusion, dissolution, bond breaking and bond formation, e.g., covalent and/or non-covalent bond breaking and formation; hydrophobic or hydrophilic interactions; and structural conformations, e.g., folding, and formation of helices and sheets.

Other aspects, features, and advantages are in the description, drawings, and claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of a pressure cycling system.

FIGS. 2A through 2C are perspective, side, and cross-sectional views of a reaction vessel. FIG. 2D is a detailed cross-section view of a cover attachment for the reaction vessel of FIGS. 2A through 2C.

FIGS. 3A and 3B are perspective and cross-sectional views of a sample vessel.

FIGS. 4A through 4C are perspective, side, and cross-sectional views of a pressure intensifies FIGS. 5A and 5B are perspective and cross-sectional views of a pressure intensifier and reaction vessel assembly.

FIG. 5C is a detailed cross-sectional view of a check- valve tee of the intensifier and reaction vessel assembly of FIGS. 5A and 5B.

FIG. 6 is a schematic view of a pressure cycling system. FIG. 7 is a graph illustrating a pressure-time profile of a pressure cycle of a pressure cycling system.

FIG. 8 is a display showing a pressure-time profile of a pressure cycling system in graphical format.

FIGS. 9 A and 9B are orthogonal front and side views of a reaction vessel and vessel cover assembly.

FIGS. 9C and 9D are cross-sectional views of the reaction vessel and vessel cover assembly of FIGS, 9A and 9B. FIG. 10 is a cross-sectional view of a reaction vessel with a thermally regulated fluid jacket.

DETAILED DESCRIPTION

Referring to FIG. 1, a pressure cycling system 10 includes a reaction vessel 11, a pre-charge circuit 40, a pressure intensifier 60, and a control circuit 100. Reaction vessel 11 receives and retains a sample 31 (see, e.g., FIG. 2C) for exposure to pressure cycling (e.g., for inhibiting and/or inducing chemical reactions of the sample). The pre-charge circuit 40 is in fluid communication with the reaction vessel 11 and is configured to deliver fluid (e.g., water) from a fluid source 42 (e.g., fluid reservoir) to the reaction vessel 11. The volume of fluid provided by the pre-charge system 40 determines a minimum pressure level within the reaction vessel 11 during pressure cycling.

The pressure cycling system 10 also includes a pressure intensifier 60 in fluid communication with the reaction vessel 11. The pressure intensifier 60 is operable to adjust the pressure level within the reaction vessel 11. Pressure generated by the pressure intensifier 60 determines a high pressure level within the reaction vessel 11. The control circuit 100 communicates with the pre-charge circuit 40 and the pressure intensifier 60 to control a pressure level within the reaction vessel 11 based on both sensed system data and user input. The control circuit 100 includes a controller 101 configured to communicate with the pre-charge system 40 for controlling the flow of fluid toward the reaction vessel 11. The control circuit 100 also includes a electronic pressure regulator 102 and a directional control valve 103. Controller 101 operates in cooperation with the electronic pressure regulator 102 and the directional control valve 103 to control a flow of pressurized gas (e.g., pressurized CO ₂ , air, an inert gas, e.g., argon, nitrogen, etc ) from a pressurized gas source 61 (e.g., an air compressor, compressed gas bottle, lab line air, etc.) toward the pressure intensifier 60, i.e., for driving the pressure intensifier 60.

Referring to FIGS. 2A-2D, the reaction vessel 11 defines a reaction chamber 12 for receiving a sample vessel 30 containing a sample 31. The reaction vessel 11 also defines a first fluid port 13, which permits the flow of fluids into and out of the reaction

chamber 12. An aperture 14 extending between the reaction chamber 12 and an outer surface of the reaction vessel 11 allows for the placement of the sample vessel 30 into the reaction chamber 12.

A removable cover 15 forms a releasable connection with the aperture 14 and provides a hermetic barrier between the reaction chamber 12 and atmospheric pressure. As shown, for example, in FIGS. 2C and 2D, the cover 15 includes an o-ring 16 which provides an air and fluid tight seal between the cover 15 and the wall of the reaction chamber 12. The cover 15 also includes a venting button 17 which is actuable to evacuate gas and/or fluid from the reaction chamber 12 through a venting bore 18 (i.e., for relief of pressure within the reaction chamber 12). More specifically, the cover 15 defines a vent chamber 19, which is in fluid communication with the venting bore 18. The cover 15 also defines a vent conduit 20, which is in fluid communication with the vent chamber 19. When the cover 15 is disposed within the aperture 14 (as shown in FIG. 2C), the vent conduit 20 and the vent chamber 19 provide a flow pathway allowing for the flow of fluids and/or gases from the reaction chamber 12 to the venting bore 18. The venting button 17 is connected (i.e., via a stem 21) to a guide bearing 22, which is slidably disposed in the vent chamber 19. The guide bearing 22 is connected to a first end of a push rod 23. The push rod 23 extends from the guide bearing 22, in the vent chamber 19, through the vent conduit 20 and terminates at a ball stop 24. When the venting button 17 is in a first position (shown in hidden lines in FIG. 2C), the ball stop 24 engages a first end 25 of the vent conduit 20 thereby forming a check valve that inhibits the flow of fluids and/or gases between the first end 25 of the vent conduit 20 and the venting bore 18. When the venting button 17 is actuated or pressed (e.g., as indicated by arrow 26) the ball stop 24 is displaced away from first end 25 of the venting conduit 20, thereby allowing fluids and/or gases to flow from the reaction chamber 21 to the vent chamber 19 and out of the venting bore 18. A drain line 27 (e.g., a flexible hose) can be provided between the venting bore 18 and the fluid reservoir 42 to allow for the recovery of fluids evacuated from the reaction chamber 21.

The cover 17 is held in place within the aperture 14 with the aid of dowel pins 28a, which are held together by a dowel handle 28b. The dowel pins 28a engage corresponding holes 29a, 29b in the cover 15 and reaction vessel 11. Cover 15 can be removed from the reaction vessel 11 to allow access to the reaction chamber 12 (i.e., for insertion and removal of the sample vessel 30).

Referring to FIGS. 3A and 3B, the sample vessel 30 defines a sample chamber 32 to receive the sample 31. Sample vessel 30 includes a removable cap 33 that provides access to the sample chamber 32 for insertion and removal of the sample 31. The sample vessel 30 also includes a plunger 35. The plunger 35 is displaceable (as indicated by 5 arrow 119) under pressure to adjust the volume, and as a result, the pressure, of the sample chamber 32. Suitable sample vessels 30 are available commercially under the trade name PULSE ^tm Tubes from Pressure BioSciences Inc. of West Bridgewater, MA.

Referring to FIGS. 4A-4C, the pressure intensifier 60 includes a pneumatic cylinder 62 and a fluid cylinder 72, which are fastened to each other through a truss 80. o The pneumatic cylinder 62 is secured between first and second mounting plates 81a, 81b, which are fastened together with first fastener elements 82. A first flange 83a of the truss 80 is mounted to the first mounting plate 81a with second fastener elements 83. The reaction vessel 11 is secured between a second flange 83b of the truss 80 and a third mounting plate 81c with third fastener elements 84.5 As shown in FIG. 4B and 4C, the pneumatic cylinder 62 defines a pneumatic chamber 63 which houses a piston 64. The piston 64 includes a first extension rod 65 which extends through a first washer 66, disposed between the pneumatic cylinder 62 and the first mounting plate 81a, and into the truss 80. Truss 80 defines a truss chamber 85 which receives the first extension rod 65 from the pneumatic cylinder 62. A second0 extend rod 67 is mounted to a distal end 68 of the first extension rod 65 within the truss chamber 85. A distal end 69 of the second extension rod 67 extends into the fluid cylinder 72 through washer assembly 71. Washer assembly 71 provides a fluid seal between the second extension rod 67 and the fluid cylinder 72.

The first and second mounting plates 81a, 81b define first and second cylinder5 ports 70a, 70b, respectively, which are in communication with the pneumatic chamber 63. The first and second cylinder ports 70a, 70b provide a conduit for the flow of pressurized gas into and out of the pneumatic chamber 63 (i.e., to control displacement of the piston 64).

The fluid cylinder 72 defines a fluid chamber 73 which receives the second0 extension rod 67. A bearing 74 is provided to guide and support the second extension rod 67 within the fluid chamber 73. The fluid cylinder 72 also defines a second fluid port 75, which permits the flow of fluids into and out of the fluid chamber 73. The piston 64 is

displaceable along the pneumatic chamber 63 (as indicated by arrows 120) to adjust the volume the fluid chamber 73.

As shown in FIGS.5A-5C, the reaction vessel 11 is connected the pressure intensifier 60 through a check- valve tee 90. A first pipe section 91 is fastened between the reaction vessel 11 and the check-valve tee 90. The first pipe section 91 provides a first fluid conduit 92 between the first fluid port 29 and a first fluid pathway 93 of the check-valve tee 90. A second pipe section 94 is fastened between the pressure intensifier 60 and the check-valve tee 90. The second pipe section 94 provides a second fluid conduit 95 between the second fluid port 75 and the first fluid pathway 93 of the check- valve tee 90. Together, the first pipe section 91, the check-valve tee 90, and the second pipe section 94 allow for the transfer of fluid between the pressure intensifier 60 and the reaction vessel 11. The check-valve tee 90 also includes a second fluid pathway 96 which extends between an inlet port 97 and the first fluid pathway 93. A check-valve 98 (shown schematically in FIG. 5C) is disposed within the second fluid pathway 96. The check- valve 98 allows for the flow of fluid from the inlet port 97 toward the first fluid pathway 93, while, at the same time, inhibits flow in the opposite direction (i.e., from the first fluid pathway 93 toward the inlet port 97. Thus, fluid flowing from an external source (as indicated by arrow 122) is allowed to enter the reaction chamber 12 and the fluid chamber 73 through inlet port 97, but will be inhibited from escape causing pressure to build in the fluid region between the reaction chamber 12 and the fluid chamber 73.

Referring to FIG. 6, the pre-charge circuit 40 delivers fluid to the reaction vessel 11 through the check- valve tee 90. The pre-charge circuit 40 includes a charge pump 41 driven by relay 43, a fluid reservoir 42, and a pressure sensor 44.

The controller 101 controls operation of the charge pump 41, which, in turn, controls the flow of fluid from the fluid reservoir 42 to the check- valve tee 90. The pressure sensor 44, together with the controller 101, monitors fluid pressure in the flow line 45 between the charge pump 41 and the check-valve tee 90. The fluid pressure will increase as the reaction vessel 11 is filled with fluid. Once the pressure sensor 44 detects a line pressure indicating that the reaction vessel 11 is charged to the predetermined minimum (pre-charge) pressure level (e.g., between about 150 and 200 psi), the controller 101 will discontinue operation of the charge pump 41 to inhibit further flow to the reaction vessel 11.

The controller 101 also controls operation of the electronic pressure regulator 102. Once the pressure sensor 44 detects that the reaction vessel 11 is pre-charged to the minimum pressure level, the controller 101 will command the electronic pressure regulator 102 to allow for the flow of compressed gas from an external pressure source 61 (e.g., compressed gas, e.g., CO ₂ , at 90 psi or greater, e.g., 800 psi) to the pressure intensifier 60. Pressurized gas from supply 118 is delivered through a first pressure regulator 142 toward the electronic pressure regulator 102. The first pressure regulator 142 drops the pressure down to a level that the electronic pressure regulator 102, and other system components, can handle. Pressurized gas flows from the electronic pressure regulator 102 to the pressure intensifier 60 through directional control valve 103, which is also controlled by the controller 101.

Directional control valve 103 controls the direction of the flow of the pressurized gas into the pneumatic cylinder 61, alternating between fist and second cylinder ports 70a, 70b. At start-up, e.g., prior to pre-charge, directional control valve 103, under the direction of the controller 101, is set to an intensifier retract position connecting the electronic pressure regulator 102 to the first cylinder port 70a and connects the second cylinder port 70b to a drain line 110. The controller 101 sets the electronic pressure regulator 102 to a nominal pressure value (e.g., 10 psi) to force pressurized gas toward a first surface 64a of the piston 64, to cause piston 64 to move to a fully retracted position (i.e., a position coincident with a maximum volume of the fluid chamber 73 (see, e.g., FIG. 4C)). Once the reaction vessel 11 reaches the pre-charge pressure, the controller 101 readjusts the directional control valve 103 to an intensifier extend position connecting the electronic pressure regulator 102 to the second cylinder port 70b and connecting the first cylinder port 70a to the drain line 110 allowing the pressurized gas to drain through muffler 104. Then, the controller 101 will control the flow of pressurized gas through the electronic pressure regulator 102 to force pressurized gas towards a second surface 64b of the piston 64 to cause the piston 64 to move toward an extended position decreasing the available fluid volume of the fluid chamber 73 (FIG. 4C), and, as a result, causing pressure within the reaction chamber 12 to increase. The controller 101 sets the output of the electronic pressure regulator 102 to a calculated output pressure applied to the pressure intensifier 60.

By maintaining a controlled gas pressure on the pneumatic cylinder 62, a controlled high pressure is generated in the reaction chamber 12. For pressure cycling,

the pressure applied to the pneumatic cylinder 62 can be varied over time to cause the pressure within the reaction chamber 12 to cycle between the low and high pressure levels.

As shown in FIG. 5, the control circuit 100 can include a cover safety sensor 106 for sensing the presence of the cover 15 (see, e.g., FIG. 2D) in the proper position in the reaction vessel 11. The controller 101 can be configured to inhibit operation of the system components in response to feedback from the cover safety sensor 106 indicating that the cover 15 is not in proper position for pressurization of the reaction chamber 12. The control circuit 100 can also include an end-of-stroke (EOS) sensor 107. The end-of- stroke sensor 107 detects an end-of-stroke condition, indicating that the piston 64 has reached a position of maximum forward displacement without achieving the high pressure level within the reaction chamber 12. The controller 101 can be configured to inhibit operation of the system components in response to feedback from the EOS sensor 107 indicating that the piston 65 has reached the end-of-stroke position. As shown in FIG. 6, the control circuit 100 includes a user input 108, and a display 109 for showing system performance. The user input 108 allows a user to enter process parameters into the controller 101. Referring to FIG. 7, the process parameters can include one or more of the following:

• Target pressures: o Target high pressure value Pl, e.g., with a range of between about

3,500 psi and about 35,000 psi; and o Target low pressure value P2, e.g., with a range of between about 150 psi and about 35,000 psi;

• Linear pressure ramp time: tl and t3, e.g., with a range of between about 0.1 seconds and about 199 seconds;

• Static pressure hold time: t2 and t4 (i.e., the dwell time (t2) at the high pressure value after the pressure is pulsed from the low pressure value and the dwell time (t4) at the low pressure value after the pressure is pulsed from the high pressure value, e.g., with a range of between about 5 seconds and about 100 hours (e.g., to incubate the growth of deep sea microorganisms);

• Ambient pressure hold time between cycles, e.g., with a range of between about 1 second and about 100 hours; and/or

• Number of cycles (N), e.g., with a range of between 1 and 99 cycles.

The inputs may be reaction specific. In one example, Pl can be lower than P2 to germinate bacterial spores followed by higher pressure lysis. In this example, tl can be relatively long to allow germination and t2 could be shorter. In another example, Pl can be relatively high to thermodynamically change the structure of proteins and generate metastable morphologies and t3 can be relatively long to preserve these morphologies as a lower pressure P2 is reached.

As illustrated in FIG. 8, for example, the display 109 can be used to show the pressure profile of the system in graphical format. Referring to FIG. 8, the solid line 130 represents an intended pressure profile, as determined from user input (i.e., user entered process parameters) and/or default system settings, while the dashed line 132 represents an actual profile achieved. The two profiles may not be exactly identical due to the power capacity of the compressed gas system used and the maximum pressure available. In use, the system 10 is powered up and the electronic pressure regulator 102 is set to 10 psi. The directional control valve 103 is set to the intensifier retract position, allowing the piston 65 to retract to a minimum pressure level position. The desired pressures (e.g., high pressure level and low pressure level), hold times, and other process parameters are entered into the controller 101 through the user input 108. Next, sample 31 is deposited in the sample vessel 30, and the sample vessel 30 is filled with fluid 36, e.g., water or silicon oil, to allow applied pressure to be transferred to the capsule. Fluid 36 aids the system in reaching the maximum pressure capability of the pressure intensifier 60. The sample vessel 30 is inserted into the reaction chamber 12 through aperture 14. Then, the cover 15 is inserted by simultaneously depressing the cover venting button 17 and pushing down on the cover 15. This allows for the venting of excess air and/or fluid from the reaction chamber 12. Once the cover 15 is in position, the dowel pins 28a can be inserted to lock the cover 15 in place. At this point the pressure in the reaction chamber 12 is about 0 psi.

With confirmation from the cover safety sensor 106 that the cover 15 is in the proper position, the process is allowed to proceed. The charge pump 41 is activated to fill the reaction chamber 12 to the pre-charge pressure P2 (e.g., between about 150 and about 200 psi). The pressure sensor 44 signals the controller 101 once the reaction chamber 12 has reached the pre-charge pressure. Then, the controller 101 turns the charge pump 41

off, shifts the directional control valve 103 into the intensifier forward position, and commands the electronic pressure regulator 102 to pressurize the pressure intensifier 60 such that pressure within the reaction chamber 12 is elevated to the high pressure level Pl, as defined by the process parameters. If the EOS sensor 107 detects an end-of-stroke condition, or, if the cover safety sensor 106 detects that the cover 15 is not in the proper position, the system 10 will indicate an error and depressurize the pressure intensifier 60.

During pressure cycling, the controller 101 controls the pressure in the reaction chamber 12 through the electronic pressure regulator 102. Utilizing the electronic pressure regulator 102, the controller 101 fluctuates the pressure in the reaction chamber 12 between the low pressure level (e.g., a reaction permissive pressure, e.g., between about 150 psi and about 35,000 psi) and the high pressure level (e.g., between about 3,500 psi and about 35,000 psi, e.g., a reaction inhibitory pressure). Depressurization of the pressure intensifier 60 can be achieved by setting the electronic pressure regulator 102 to 0 pressure (i.e., 0 psi). During pressure cycling, the system pressure is monitored by the gas pressure sensor 105. The controller 101 scales a feedback signal from the gas pressure sensor 105 to calculate the pressure in the reaction chamber 12 before display.

At the end of the run, the directional control valve 103 is de-energized, connecting both of the first and second cylinder ports 70a, 70b to the drain line 110, thereby allowing the piston 64 to retract, under system pressure, to the minimum pressure level position (i.e., high pressure decompression). Following high pressure decompression, the pre- charge pressure can be released by depressing the cover venting button 17. Fluid can also be purged from the reaction chamber 12 by simultaneous actuating the charge pump 41 and depressing the cover venting button 17.

Once the reaction chamber 12 has been vented to 1 atm, the cover 15 can be removed by withdrawing the dowel pins 28a and the sample vessel 30 can be withdrawn.

While certain embodiments have been described above, other embodiments are possible.

As an example, FIGS. 9A-9D illustrate another embodiment of a reaction vessel 11 ' and removable cover 15' assembly. As shown, for example, in FIGS. 9C and 9D, rather than evacuating fluid directly out of the cover 15' (e.g., through a venting bore), fluid discharged from a reaction chamber 12' is redirected from a vent conduit 20' through a flow pathway, defined by first and second draining channels 34a, 34b, toward a drain region 37 within an aperture 14' of the reaction vessel 11'. As shown in FIG. 9C,

for example, the first and second draining channels 34a, 34b can include a pair of drilled holes. A first hole (i.e., first draining channel 34a) is formed (e.g., drilled) which extends from a first surface 38a of the cover 15' into the vent conduit 20' . A blocking ball 39 is inserted into the first hole in order to seal the hole along the first surface of the cover 15' . 5 A second hole (i.e., second draining channel 34b) is formed, which extends from a second surface 38b of the cover 15' into the first draining channel 34a.

Referring to FIGS. 9C and 9D, the reaction vessel 11' includes a seal 46 (e.g., an O-ring seal) disposed within a groove 47 in a wall of the aperture 14'. The seal 46 marks a boundary of the drain region 37; the drain region 37 being the region within the aperture o 22' below the seal 46. The seal 46 creates a hermetic barrier with the first surface 38a of the cover 15' to inhibit the flow of discharged fluid from the drain region 37 past the seal 46. As shown in FIG. 9D, the reaction vessel 11' includes a drain bore 48 in fluid communication with the second draining channel 34b. Fluid and/or gases exiting the reaction chamber 12' through the vent conduit 20' will be directed to the drain region 375 and subsequently discharged through the draining bore 48. A drain line 27' (e.g., a flexible hose) can be provided between the draining bore 48 and the fluid reservoir 42 to allow for the recovery of fluids evacuated from the reaction chamber 12' .

Referring to FIGS. 9C and 9D, in operation, friction between the seal 46 and the cover 15' and between the o-ring 16' and the wall of the reaction chamber 12' can make0 removal of the cover 15' forceful. With the dowel pins 28a removed, a pressure assisted lifting feature can be provided by utilizing the pressure within the reaction chamber 12' to lift the cover 15' past the o-ring 16' seal engagement zone (i.e., out of high pressure contact with the wall of the reaction chamber 12'). In one example, the pressure of the reaction chamber 12' is maintained at about 150 psi, and the seal diameter of the o-ring5 16' is about 7 inches, thereby creating a lifting force of about 57 pounds. Once the cover 15' is lifted past the o-ring 16' engagement zone, the reaction chamber 12' is placed in direct fluid communication with the drain region 37 allowing fluid to drain, thereby causing the pressure in the reaction chamber 12' to drop. At this point, the cover 15' will no longer continue to move up and the seal 46 is almost disengaged from contact with the0 first surface 38a of the cover 15' . Seal 46 can be a relatively loose fitting seal requiring only hand force to remove the cover 15' from the aperture 14'.

In some embodiments, different controllers can have different capabilities. For example, in some embodiments, the controller allows for pressure ramping on

pressurization and depressurization. In another example, the controller can cycle pressure between multiple additional distinct set points (e.g., 4, 5, or more) rather the exemplary three distinct pressure approach described above. In another embodiment, the pressure can be varied according to a computer-controlled wave form. In some embodiments, the control circuit can include a pressure transducer (see, e.g., FIG. 6, item 140) arranged in fluid communication with the reaction chamber for direct measuring pressure within the reaction chamber.

In some implementations, the system can include a fluid drain line connecting the outlet port on the cover with fluid reservoir for recovery of purged fluid. In some implementations, other combinations of equipment can be used to implement the concepts described above. For example, in some embodiments, the pressure intensifier and the reaction vessel can be a single unit rather than two connected units.

While the pressure cycling systems of the embodiments described above include a charge pump that is controlled by the system controller, some systems can have a manual override mode for manual pre-charge control.

In some embodiments, high pressure cycling (i.e., control over the flow of pressurized gas to the pressure intensifier) can be conducted manually in addition to or as an alternative to the automated control described above. In some implementations, the systems can include hand valve (see, e.g., FIG. 6, item 144) to provide manual control over the flow of pressurize gas between the gas source and the electronic pressure regulator.

In some embodiments, the reaction chamber and the intensifier fluid chamber can be integrated into a single unit. In some implementations, where the charge pressure is not needed, the systems can operate without the charge pump (i.e., in some cases the charge pump can be absent).

In some embodiments, the reaction chamber is made from or lined with a material (e.g., stainless steel) that is chemically compatible with the sample being processed.

In some implementations, the systems can include temperature control for the reaction chamber. For example, as shown in FIG. 10, in some cases the reaction vessel 11 is surrounded by a cooling and/or heating jacket 146 to control the temperature of the reaction chamber. Referring to FIG. 10, jacket 146 includes inlet and outlet ports 147, 148, respectively, which permit a temperature regulated fluid (e.g., from a fluid reservoir

(not shown) to be circulated into chamber 149 surrounding the reaction vessel 11. O-rings 150, 151 provide a fluid seal for jacket 146. The temperature of reaction chamber 12 can be controlled within a range of about -40 ⁰ C. to 100 ⁰ C.

Accordingly, other embodiments are within the scope of the following claims.