Patent Publication Number: US-11047401-B2

Title: Electrohydraulic normally-open ventable valve configured to operate in pressure relief mode when actuated

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is a continuation of U.S. patent application Ser. No. 16/133,972, filed on Sep. 18, 2018, and entitled “Electrohydraulic Normally-Open Ventable Valve Configured to Operate in Pressure Relief Mode When Actuated,” the entire contents of which are herein incorporated by reference as if fully set forth in this description. 
    
    
     BACKGROUND 
     A relief valve or pressure relief valve (PRV) is a type of safety valve used to control or limit the pressure in a system. Pressure might otherwise build up and can cause equipment failure. The pressure is relieved by allowing the pressurized fluid to flow out of the system to a tank or low pressure fluid reservoir. In some applications, a PRV can be used to build pressure level of fluid up to a particular pressure level to operate a hydraulic system or component. 
     A PRV is designed or set to open at a predetermined setting pressure to protect other components and other equipment from being subjected to pressures that exceed their design limits. When the setting pressure is exceeded, the PRV becomes or forms the “path of least resistance” as the PRV is forced open and a portion of fluid is diverted to the tank. As the fluid is diverted, the pressure inside the system stops rising. Once the pressure is reduced and reaches the PRV&#39;s reseating pressure, the PRV closes. 
     SUMMARY 
     The present disclosure describes implementations that relate to an electrohydraulic normally-open ventable valve configured to operate in pressure relief mode when actuated. 
     In a first example implementation, the present disclosure describes a valve. The valve includes: (i) a pilot seat member comprising: (a) one or more channels fluidly coupled to a first port of the valve, (b) a pilot seat, and (c) a pilot sleeve portion comprising a pilot chamber and a cross-hole disposed in an exterior peripheral surface of the pilot sleeve portion; (ii) a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring disposed in the pilot chamber to seat the pilot check member at the pilot seat; and (iii) a solenoid actuator sleeve slidably accommodated about the exterior peripheral surface of the pilot sleeve portion of the pilot seat member, wherein the solenoid actuator sleeve includes a cross-hole disposed in an exterior peripheral surface of the solenoid actuator sleeve, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to a second port of the valve. When the valve is unactuated, the cross-hole of the solenoid actuator sleeve is fluidly coupled to the one or more channels of the pilot seat member to form a first pilot flow path from the first port to the second port, thereby causing a piston to move and open a main flow path from the first port to the second port. When the valve is actuated, the solenoid actuator sleeve moves axially, thereby: (i) blocking the first pilot flow path, (ii) causing the piston to block the main flow path from the first port to the second port, and (iii) aligning the cross-hole of the solenoid actuator sleeve with the cross-hole of the pilot sleeve portion, such that when pressure level of fluid at the first port overcomes the biasing force of the setting spring on the pilot check member, the pilot check member is unseated and a second pilot flow path is formed from the first port to the second port, thereby causing the piston to move axially and open the main flow path from the first port to the second port. 
     In a second example implementation, the present disclosure describes a hydraulic system including a source of fluid; a reservoir; and a ventable pressure relief valve having a first port fluidly coupled to the source of fluid, and a second port fluidly coupled to the reservoir. The ventable pressure relief valve comprises: (i) a pilot seat member comprising: (a) one or more channels fluidly coupled to the first port, (b) a pilot seat, and (c) a pilot sleeve portion comprising a pilot chamber and a cross-hole disposed in an exterior peripheral surface of the pilot sleeve portion; (ii) a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring disposed in the pilot chamber to seat the pilot check member at the pilot seat; and (iii) a solenoid actuator sleeve slidably accommodated about the exterior peripheral surface of the pilot sleeve portion of the pilot seat member, wherein the solenoid actuator sleeve includes a cross-hole disposed in an exterior peripheral surface of the solenoid actuator sleeve, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to the second port. When the ventable pressure relief valve is unactuated, the ventable pressure relief valve operates in a ventable mode of operation, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to the one or more channels of the pilot seat member to form a first pilot flow path from the first port to the second port, thereby causing a piston to move and open a main flow path from the first port to the second port. When the ventable pressure relief valve is actuated, the ventable pressure relief valve operates in a pressure relief mode of operation, wherein the solenoid actuator sleeve moves axially, thereby: (i) blocking the first pilot flow path, (ii) causing the piston to block the main flow path from the first port to the second port, and (iii) aligning the cross-hole of the solenoid actuator sleeve with the cross-hole of the pilot sleeve portion, such that when pressure level of fluid at the first port overcomes the biasing force of the setting spring on the pilot check member, the pilot check member is unseated and a second pilot flow path is formed from the first port to the second port, thereby causing the piston to move axially and open the main flow path from the first port to the second port. 
     In a third example implementation, the present disclosure describes a valve. The valve includes: (i) a housing having a longitudinal cylindrical cavity therein and having a cross-hole disposed in an exterior peripheral surface of the housing; (ii) a main sleeve disposed, at least partially, in the longitudinal cylindrical cavity of the housing, wherein the main sleeve includes a first port at a distal end of the main sleeve and includes one or more cross-holes disposed on an exterior peripheral surface of the main sleeve, wherein the cross-hole of the housing and the one or more cross-holes of the main sleeve form a second port; (iii) a piston disposed within the main sleeve and configured to be axially movable therein, wherein the piston defines a main chamber therein, and wherein the main chamber is fluidly coupled to the first port via an orifice; (iv) a pilot seat member comprising: (a) one or more channels fluidly coupled to the main chamber, (b) a pilot seat, and (c) a pilot sleeve portion comprising a pilot chamber and a cross-hole disposed in an exterior peripheral surface of the pilot sleeve portion; (v) a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring disposed in the pilot chamber to seat the pilot check member at the pilot seat; and (vi) a solenoid actuator sleeve slidably accommodated about the exterior peripheral surface of the pilot sleeve portion of the pilot seat member, wherein the solenoid actuator sleeve includes a cross-hole disposed in an exterior peripheral surface of the solenoid actuator sleeve, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to the second port. When the valve is unactuated, the solenoid actuator sleeve is in a first position in which the cross-hole of the solenoid actuator sleeve is fluidly coupled to the one or more channels of the pilot seat member to form a first pilot flow path from the first port to the second port. When the valve is actuated, the solenoid actuator sleeve moves axially to a second position in which the first pilot flow path is blocked, and the cross-hole of the solenoid actuator sleeve is aligned with the cross-hole of the pilot sleeve portion to form a second pilot flow path when pressure level of fluid at the first port overcomes the biasing force of the setting spring on the pilot check member. 
     The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, implementations, and features described above, further aspects, implementations, and features will become apparent by reference to the figures and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  illustrates a cross-sectional side view of a valve in a ventable operation mode, in accordance with an example implementation. 
         FIG. 2  illustrates a three-dimensional perspective view showing an armature coupled to a solenoid actuator sleeve, in accordance with an example implementation. 
         FIG. 3  illustrates a cross-sectional side view of a valve in a pressure relief mode of operation, in accordance with another example implementation. 
         FIG. 4  illustrates a cross-section side view of a valve having a manual adjustment actuator, in accordance with an example implementation. 
         FIG. 5  illustrates a cross-sectional side view of a solenoid tube, in accordance with an example implementation. 
         FIG. 6  illustrates a hydraulic circuit using the valve shown in  FIG. 4 , in accordance with an example implementation. 
         FIG. 7  is a flowchart of a method for controlling a hydraulic system, in accordance with an example implementation. 
         FIG. 8  is a flowchart of a method for operating a valve, in accordance with an example implementation. 
     
    
    
     DETAILED DESCRIPTION 
     Pressure relief valves are configured to open at a preset pressure and discharge fluid until pressure drops to acceptable levels in a system. In operation, the pressure relief valve can remain normally-closed until pressure upstream reaches a desired setting pressure. The valve can then “crack” open when the setting pressure is reached, and continue to open further, allowing more flow as pressure increases. When upstream pressure falls below the setting pressure, the valve can close again. 
     In some examples, it may be desirable to have a ventable pressure relief valve that can provide system relief protection with an actuation signal (e.g., with an electrical signal) combined with the ability to “unload” a source of fluid (e.g., a pump) to a tank when unactuated. For example, the valve can operate in a ventable operation mode to unload a pump as long as a speed of an engine or motor driving the pump is below a particular threshold speed. Once the particular threshold speed, the valve can be actuated to switch to a pressure relief mode. In another example, the valve can operate in the ventable operation mode when the temperature of hydraulic oil exceeds a particular temperature threshold, and then actuated to operate in the pressure relief mode when the temperature is reduced to a value below the particular temperature threshold. In other examples, the valve can operate in the ventable operation mode to operate the hydraulic system in a safety mode, and then actuated to switch the valve to the pressure relief mode when the hydraulic system is ready to be operational. 
     It may also be desirable to have such combined functionality in a compact package that does not involve using several valves, but rather a single valve that combines multiple functionalities, thereby reducing manufacturing cost. Further, having a compact package that performs multiple functionalities reduces system size and weight. 
     Disclosed herein is a valve configured to operate in a ventable mode to maintain low system pressure until the valve is actuated. Particularly, when the valve is unactuated, the valve forms therein a first pilot flow path that is open, thereby causing the valve to operate in the ventable mode. Upon actuation, the valve is configured to block the first pilot flow path and operate as a relief valve that forms a second pilot flow path configured to allow fluid flow therethrough when a relief setting (i.e., the setting pressure) is reached. 
       FIG. 1  illustrates a cross-sectional side view of a valve  100  in a ventable operation mode, in accordance with an example implementation. The valve  100  may be inserted or screwed into a manifold having ports corresponding to ports of the valve  100  described below, and can thus fluidly coupled the valve  100  to other components of a hydraulic system. 
     The valve  100  may include a main stage  102 , a pilot stage  104 , and a solenoid actuator  106 . The valve  100  includes a housing  108  that includes a longitudinal cylindrical cavity therein. The longitudinal cylindrical cavity of the housing  108  is configured to house portions of the main stage  102 , the pilot stage  104 , and the solenoid actuator  106 . 
     The main stage  102  includes a main sleeve  110  received at a distal end of the housing  108 , and the main sleeve  110  is coaxial with the housing  108 . The valve  100  includes a first port  112  and a second port  114 . The first port  112  is defined at a nose or distal end of the main sleeve  110 . The second port  114  can include a first set of cross-holes that can be referred to as main flow cross-holes, such as main flow cross-holes  115 A,  115 B, disposed in a radial array about an exterior surface of the main sleeve  110 . The second port  114  can also include a second set of cross-holes that can be referred to as pilot flow cross-holes, such as pilot flow cross-hole  116  disposed in the housing  108 . 
     The main sleeve  110  includes a respective longitudinal cylindrical cavity therein. The valve  100  includes a piston  118  that is disposed, and slidably accommodated, in the longitudinal cylindrical cavity of the main sleeve  110 . The term “piston” is used herein to encompass any type of movable element, such as a spool-type movable element or a poppet-type movable element. The piston  118  is shown in the figures as a spool-type movable element; however, it is contemplated that a poppet-type movable element can be used instead. In the case a poppet-type movable element is used, the inner peripheral surface of the main sleeve  110  can form a protrusion that operates as a seat for the poppet-type movable element and reduce leakage through the valve  100 . 
     Further, the term “slidably accommodated” is used throughout herein to indicate that a first component (e.g., the piston  118 ) is positioned relative to a second component (e.g., the main sleeve  110 ) with sufficient clearance therebetween, enabling movement of the first component relative to the second component in the proximal and distal directions. As such, the first component (e.g., piston  118 ) is not stationary, locked, or fixedly disposed in the valve  100 , but rather, is allowed to move relative to the second component (e.g., the main sleeve  110 ). 
     The piston  118  has a cavity or main chamber  120  therein, and the valve  100  includes a main spring  122  disposed in the main chamber  120  of the piston  118 . The valve  100  also includes a ring-shaped member  124  disposed, at least partially, within the piston  118  at a distal end thereof. The ring-shaped member  124  includes a filter  126  and forms therein an orifice  128  that fluidly couples the first port  112  to the main chamber  120 . 
     The valve  100  further includes a pilot seat member  130  fixedly disposed at the proximal end of the main sleeve  110  within the cavity of the housing  108 . As shown in  FIG. 1 , the pilot seat member  130  has a shoulder formed by an exterior peripheral surface of the pilot seat member  130 . The shoulder interfaces with the proximal end of the main sleeve  110  and interfaces with a shoulder  131  formed as a protrusion from an interior peripheral surface of the housing  108 . As such, the pilot seat member  130  is fixedly disposed within the housing  108 . 
     The main spring  122  is disposed in the main chamber  120  such that a distal end of the main spring  122  rests against the interior surface of the piston  118 , and a proximal end of the main spring  122  rests against the pilot seat member  130 . The pilot seat member  130  is fixed, and thus the main spring  122  biases the piston  118  in the distal direction (to the right in  FIG. 1 ). The distal direction could also be referred to as a closing direction. The main spring  122  is configured as a weak spring (e.g., a spring with a spring rate of 8 pound-force/inch causing a 2 pound-force biasing force on the piston  118 ). With such a low spring rate, a low pressure level differential across the piston  118 , e.g., pressure level differential of 25 pounds per square inch (psi), can cause the piston  118  to move in the proximal direction against the biasing force of the main spring  122 . 
     Further, the pilot seat member  130  includes one or more channels that are fluidly coupled to the first port  112 . For example, the pilot seat member  130  can include a longitudinal channel  132  and can also include a plurality of radial channels such as radial channel  134  fluidly coupled to the longitudinal channel  132 . The longitudinal channel  132  can operate as a damping orifice, such that as fluid flows from the first port  112 , through the orifice  128  and the main chamber  120 , pressure level of the fluid can drop as it flows through the longitudinal channel  132 . 
     The pilot seat member  130  forms a pilot seat  136  at a proximal end of the longitudinal channel  132 . The pilot stage  104  of the valve  100  includes a pilot poppet  138  configured to be seated at the pilot seat  136 . In particular, with the configuration shown in  FIG. 1 , the pilot poppet  138  forms a cavity at its distal end that is configured to house a pilot check ball  139 . The pilot check ball  139  is configured to be seated at the pilot seat  136  when the valve  100  is in the ventable mode of operation depicted in  FIG. 1 . 
     The pilot poppet  138  and the pilot check ball  139  can be collectively referred to as a pilot check member  140 . The configuration of the pilot check member  140  that includes the pilot poppet  138  and the pilot check ball  139  as shown in  FIG. 1  is an example for illustration. In other examples, a pilot check member can be configured as a poppet having a nose section that tapers gradually, such that rather than using a check ball to block fluid flow, an exterior surface of the nose section of the poppet is seated at the pilot seat  136  to block fluid flow. 
     As shown in  FIG. 1 , the pilot seat member  130  has a pilot sleeve portion  141  that extends in the proximal direction within the housing  108  and forms therein a pilot chamber  142  in which the pilot poppet  138  is disposed and is slidably accommodated therein. The pilot poppet  138  is thus guided by an interior peripheral surface of the pilot sleeve portion  141  when the pilot poppet  138  moves axially in a longitudinal direction. 
     The pilot stage  104  further includes a setting spring  144  disposed in the pilot chamber  142 , such that a distal end of the setting spring  144  interfaces with the pilot poppet  138  and biases the pilot poppet  138  toward the pilot seat  136 . As such, the pilot poppet  138  operates as a distal spring cap for the setting spring  144 . 
     A proximal end of the setting spring  144  rests against a washer  146  disposed in the pilot chamber  142  and fixed in place via a spring preload adjustment screw  148 . The spring preload adjustment screw  148  has a threaded region on its exterior peripheral surface that threadedly engages with a corresponding threaded region on an interior peripheral surface of the pilot sleeve portion  141  of the pilot seat member  130 . 
     The valve  100  can further include a pin  149  that secures that spring preload adjustment screw  148  within the pilot sleeve portion  141 . For example, the pin  149  can be disposed partially within a longitudinal groove formed in the exterior peripheral surface of the spring preload adjustment screw  148  and partially within a longitudinal groove formed in the interior peripheral surface of the pilot sleeve portion  141 . As such, the pin  149  couples and secures the spring preload adjustment screw  148  to the pilot sleeve portion  141 . In an example, the pin  149  can be pushed into the longitudinal groove formed on the exterior peripheral of the spring preload adjustment screw  148 , and as the pin  149  is forced in longitudinal groove, it deforms interior threads of the pilot sleeve portion  141 . As such, once the spring preload adjustment screw  148  is screwed into the pilot seat member  130  to a particular longitudinal or axial position, and the pin  149  is inserted, positions of the spring preload adjustment screw  148  and the washer  146  are fixed, as the spring preload adjustment screw  148  can no longer rotate relative to the pilot seat member  130 . 
     The biasing force of the setting spring  144  determines the pressure relief setting of the valve  100 , where the pressure relief setting is the pressure level of fluid at the first port  112  at which the valve  100  can open to relieve fluid to the second port  114 . Specifically, based on a spring rate of the setting spring  144  and the length of the setting spring  144 , the setting spring  144  exerts a particular preload or biasing force on the pilot poppet  138  in the distal direction, thus causing the pilot check ball  139  to be seated at the pilot seat  136  of the pilot seat member  130 . The pressure relief setting of the valve  100  can be determined by dividing the biasing force that the setting spring  144  applies to the pilot poppet  138  by an effective area of the pilot seat  136 . The effective area of the pilot seat  136  can be estimated as a circular area having a diameter of the pilot seat  136 . As an example for illustration, the pressure relief setting of the valve  100  can be about 5000 psi. 
     As described below, when the valve  100  is actuated and when pressure level of fluid at the first port  112  causes the fluid to apply a force on the pilot check ball  139 , and thus on the pilot poppet  138 , in the proximal direction that overcomes the biasing force of the setting spring  144  applied on the pilot poppet  138  in the distal direction, the pilot poppet  138  and the pilot check ball  139  move off the pilot seat  136 . As the pilot check ball  139  is unseated, a pilot flow is allowed, thereby causing main flow from the first port  112  to the second port  114  and relieving the fluid as described below. 
     Adjusting longitudinal position of the spring preload adjustment screw  148  within the pilot seat member  130  (prior to installation of the pin  149 ) can adjust the biasing force of the setting spring  144 . For example, if the spring preload adjustment screw  148  is rotated in a first direction (e.g., in a clockwise direction), the spring preload adjustment screw  148  may move axially in the distal direction (e.g., to the right in  FIG. 1 ) pushing the washer  146  in the distal direction, thus compressing the setting spring  144  and increasing the preload or biasing force of the setting spring  144 . 
     Conversely, rotating the spring preload adjustment screw  148  in a second direction (e.g., counter-clockwise) causes the spring preload adjustment screw  148  to move axially in the proximal direction, allowing the setting spring  144  to push the washer  146  in the proximal direction. The length of the setting spring  144  thus increases and the preload or biasing force of the setting spring  144  is reduced. 
     In examples, the spring preload adjustment screw  148  can be hollow such that a force sensor (e.g., a pin configured to have a force sensor coupled thereto) can be inserted from the proximal end of the valve  100  (prior to installation of the solenoid actuator  106 ) through the spring preload adjustment screw  148  to contact the washer  146  and measure the biasing force of the setting spring  144 . With this configuration, if desired, the biasing force of the setting spring  144 , and thus the pressure relief setting of the valve  100 , can be adjusted by adjusting the longitudinal or axial position of the spring preload adjustment screw  148 , prior to completing assembly of the valve  100  (i.e., prior to installation of the pin  149  and the solenoid actuator  106 ). 
     The solenoid actuator  106  includes a solenoid tube  150  configured as a cylindrical housing or body disposed within and received at a proximal end of the housing  108 , such that the solenoid tube  150  is coaxial with the housing  108 . For instance, the solenoid tube  150  can have a threaded region disposed on an exterior peripheral surface at a distal end thereof that threadedly engages with a corresponding threaded region formed on an interior peripheral surface of the housing  108  at a proximal end thereof. A solenoid coil  151  can be disposed about an exterior surface of the solenoid tube  150 . The solenoid coil  151  is retained between a proximal end of the housing  108  and a coil nut  153  having internal threads that can engage a threaded region formed on the exterior peripheral surface of the solenoid tube  150  at its proximal end. 
     The solenoid tube  150  forms therein a solenoid actuator chamber configured to house a plunger or armature  152 . The armature  152  is slidably accommodated within the solenoid tube  150 . 
     The solenoid actuator  106  further includes a solenoid actuator sleeve  154  received at the proximal end of the housing  108  and also disposed partially within a distal end of the solenoid tube  150 . The solenoid actuator sleeve  154  is slidably accommodated about the exterior peripheral surface of the pilot sleeve portion  141  (i.e., the solenoid actuator sleeve  154  is positioned relative to the pilot sleeve portion  141  with sufficient clearance therebetween, enabling movement of the solenoid actuator sleeve  154  relative to the pilot sleeve portion  141  in the proximal and distal directions, and thus the solenoid actuator sleeve  154  is not stationary, locked, or fixedly disposed in the valve  100 , but rather, is allowed to move relative to the pilot sleeve portion  141 ). 
     Further, the solenoid actuator sleeve  154  includes a plurality of cross-holes, such as cross-holes  155 A,  155 B, disposed in a radial array about an exterior surface of the solenoid actuator sleeve  154  and configured to communicate fluid therethrough. 
     Further, the armature  152  is mechanically coupled to, or linked with, the solenoid actuator sleeve  154 . As such, if the armature  152  moves axially (e.g., in the proximal direction), the solenoid actuator sleeve  154  moves along with the armature  152  in the same direction. 
     The armature  152  can be coupled to the solenoid actuator sleeve  154  in several ways.  FIG. 2  illustrates a three-dimensional partial perspective view showing the armature  152  coupled to the solenoid actuator sleeve  154 , in accordance with an example implementation. As shown, the solenoid actuator sleeve  154  can have a male T-shaped member  200 , and the armature  152  can have a corresponding female T-slot  202  configured to receive the male T-shaped member  200  of the solenoid actuator sleeve  154 . With this configuration, the armature  152  and the solenoid actuator sleeve  154  are coupled to each other, such that if the armature  152  moves, the solenoid actuator sleeve  154  moves therewith. 
     Referring back to  FIG. 1 , the solenoid tube  150  further includes a pole piece  156  that can be separated from the armature  152  by an airgap  158 . The pole piece  156  can be composed of material of high magnetic permeability. 
     The armature  152  includes therein a channel  160  and a chamber  162  formed within the armature  152  at a proximal end thereof. The chamber  162  is thus bounded by an interior surface of the pole piece  156  and an interior surface of the armature  152 . As such, fluid received at the first port  112  can be communicated through unsealed spaces within the valve  100  to the channel  160 , then to the chamber  162  and the airgap  158 . With this configuration, the armature  152  can be pressure-balanced with fluid acting on both its proximal and distal ends. 
     Further, in examples, the chamber  162  can house a solenoid spring  164  that biases the armature  152  toward the solenoid actuator sleeve  154  and the pilot sleeve portion  141  such that there is no axial clearance or axial “play” between the armature  152 , the solenoid actuator sleeve  154 , and the pilot sleeve portion  141 , thus maintaining contact therebetween, when the valve  100  is unactuated. When the valve  100  is actuated, as described below, the armature  152  can move in the proximal direction against the force of the solenoid spring  164 , and thus the solenoid actuator sleeve  154  can move relative to (e.g., slide about the exterior peripheral surface of) the pilot sleeve portion  141 , which is fixed. The solenoid spring  164  can be a weak spring that applies a low force on the armature  152 . As an example for illustration, the solenoid spring  164  can have a spring rate of 30 pound-force/inch causing a force of about 2.5 pound-force on the armature  152 . 
     The valve  100  is configured to operate in at least two modes of operation. The first mode of operation when the valve  100  is unactuated can be referred to as the ventable mode of operation and is depicted in  FIG. 1 . In this mode of operation, as shown in  FIG. 1 , the solenoid actuator sleeve  154  is in a first position, where the radial channel  134  of the pilot seat member  130  is overlapped, at least partially, with the cross-holes  155 A,  155 B of the solenoid actuator sleeve  154 . In other words, the cross-holes  155 A,  155 B of the solenoid actuator sleeve  154  are aligned with, and fluidly coupled to, the radial channel  134  of the pilot seat member  130 . Thus, fluid received at the first port  112  can flow through the orifice  128 , the main chamber  120 , the longitudinal channel  132 , and the radial channel  134  to the cross-holes  155 A,  155 B. 
     As shown in  FIG. 1 , an exterior diameter of the solenoid actuator sleeve  154  is smaller than an interior diameter of the housing  108 , and thus annular space  166  is formed therebetween. Also, the pilot seat member  130  includes a plurality of longitudinal channels or through-holes such as longitudinal through-hole  168  disposed in a radial array around the pilot seat member  130 . Further, the longitudinal through-hole  168  is fluidly coupled to the pilot flow cross-hole  116  of the housing  108  via an annular undercut or annular groove  170  formed on the exterior peripheral surface of the main sleeve  110  at a proximal end thereof. 
     As such, in the ventable valve mode of operation, fluid received at the first port  112  flows to the second port  114  through the orifice  128 , the main chamber  120 , the longitudinal channel  132 , the radial channel  134 , the cross-holes  155 A,  155 B, the annular space  166 , the longitudinal through-hole  168 , the annular groove  170 , and the pilot flow cross-hole  116 . Such fluid flow from the first port  112  to the second port  114  through the pilot flow cross-hole  116  can be referred to as the pilot flow. As an example for illustration, the pilot flow can amount to about 0.15 gallons per minute (GPM). 
     With this configuration, in the ventable mode of operation, when the valve  100  is unactuated (i.e., when the solenoid coil  151  is un-energized), the valve  100  forms a first pilot flow path from the first port  112  through the orifice  128 , the main chamber  120 , the longitudinal channel  132 , the radial channel  134 , the cross-holes  155 A,  155 B, the annular space  166 , the longitudinal through-hole  168 , the annular groove  170 , and the pilot flow cross-hole  116  to the second port  114 . The first pilot flow path is normally-open, i.e., when the valve  100  is in an unactuated state, the first pilot flow path through the radial channel  134  is open. 
     The pilot flow through the orifice  128 , which operates as a flow restriction, causes a pressure drop in the pressure level of the fluid. Thus, the pressure level of fluid in the main chamber  120  becomes lower than the pressure level of fluid received at the first port  112 . As a result, fluid at the first port  112  applies a force on the distal end of the piston  118  in the proximal direction (e.g., to the left in  FIG. 1 ) that is larger than the force applied by fluid in the main chamber  120  on the proximal end of the piston  118  in the distal direction (e.g., to the right in  FIG. 1 ). 
     Due to such force imbalance on the piston  118 , a net force is applied to the piston  118  in the proximal direction. When the net force overcomes the biasing force of the main spring  122  on the piston  118 , the net force causes the piston  118  to move or be displaced axially in the proximal direction against the biasing force of the main spring  122 . As mentioned above, the main spring  122  has a low spring rate, and thus a small pressure drop (e.g., when the pressure drop across the orifice  128  is about 25 psi) can cause the net force to overcome the biasing force of the main spring  122  on the piston  118 . The piston  118  can move in the proximal direction until the proximal end of the piston  118  interfaces with or contacts the distal end of the pilot seat member  130 , which operates as a stop for the piston  118 . 
     In the position shown in  FIG. 1 , i.e., when the piston  118  has moved in the proximal direction, the main flow cross-holes  115 A,  115 B are exposed, and thus fluid received at the first port  112  is allowed to flow through the main flow cross-holes  115 A,  115 B directly to the second port  114 . In other words, a main flow path is formed from the first port  112  directly through the main flow cross-holes  115 A,  115 B to the second port  114 . Such direct flow from the first port  112  to the second port  114  can be referred to as the main flow. As an example for illustration, the main flow rate can amount to up to 25 GPM based on the pressure setting of the valve  100  and the pressure drop between the first port  112  and the second port  114 . The 25 GPM main flow rate is an example for illustration only. The valve  100  is scalable in size and different amounts of main flow rates can be achieved. 
     The second port  114  can be coupled to a low pressure reservoir or tank having fluid at low pressure level (e.g., atmospheric or low pressure level such as 10-70 psi). As such, fluid at the first port  112  is vented to the tank, and pressure level does not build up or increase at the first port  112 . 
     As a result, the pressure level of fluid communicated through the longitudinal channel  132  and acting on the pilot check ball  139  is not sufficient to overcome the biasing force of the setting spring  144 . Therefore, the pilot poppet  138  and the pilot check ball  139  remain seated at the pilot seat  136 , precluding fluid flow to within the pilot sleeve portion  141 . 
     The pilot sleeve portion  141  includes cross-holes, such as cross-holes  172 A,  172 B disposed in a radial array about the pilot sleeve portion  141 . The cross-holes  172 A,  172 B are fluidly coupled to an annular groove  174  formed in an exterior peripheral surface of the pilot sleeve portion  141 . In the ventable valve mode of operation depicted in  FIG. 1 , because the pilot check ball  139  remain seated at the pilot seat  136 , fluid is not communicated to the cross-holes  172 A,  172 B or the annular groove  174 . 
     The valve  100  is further configured to operate in a second mode of operation, which can be referred to as a pressure relief mode, when actuated. In other words, when the solenoid actuator  106  is activated, the valve  100  switches to a pressure relief mode of operation. 
       FIG. 3  illustrates a cross-sectional side view of the valve  100  in a pressure relief mode of operation, in accordance with an example implementation. When an electric current is provided through the windings of the solenoid coil  151 , a magnetic field is generated. The pole piece  156  directs the magnetic field through the airgap  158  toward the armature  152 , which is movable and is attracted toward the pole piece  156 . In other words, when an electric current is applied to the solenoid coil  151 , the generated magnetic field forms a north and south pole in the pole piece  156  and the armature  152 , and therefore the pole piece  156  and the armature  152  are attracted to each other. Because the pole piece  156  is fixed and the armature  152  is movable, the armature  152  can traverse the airgap  158  toward the pole piece  156 , and the airgap  158  is reduced in size as depicted in  FIG. 3 . As such, a solenoid force is applied on the armature  152 , where the solenoid force is a pulling force that tends to pull the armature  152  in the proximal direction against the force of the solenoid spring  164 . 
     The solenoid force applied to the armature  152  is also applied to the solenoid actuator sleeve  154 , which is coupled to the armature  152  as described with respect to  FIG. 2 . As the solenoid actuator sleeve  154  moves in the proximal direction (to the left in  FIG. 3 ) to a second position shown in  FIG. 3 , the cross-holes  155 A,  155 B of the solenoid actuator sleeve  154  move away from the radial channel  134  of the pilot seat member  130 . 
     As such, the first pilot flow path described above is blocked and no pilot flow is allowed from the first port  112  to the second port  114  therethrough. In other words, as the solenoid actuator sleeve  154  moves in the proximal direction and the cross-holes  155 A,  155 B of the solenoid actuator sleeve  154  are no longer fluidly coupled to, or overlapping with, the radial channel  134  as shown in  FIG. 3 , flow from the first port  112  to the second port  114  through the orifice  128 , the main chamber  120 , the longitudinal channel  132  and the radial channel  134  is blocked by the solenoid actuator sleeve  154 . As a result, no pressure drop occurs across the orifice  128 , and the piston  118  becomes pressure-balanced due to the pressure level of fluid at the first port  112  and within the main chamber  120  being substantially the same. The piston  118  then moves back in the distal direction by the biasing force of the main spring  122  to block the main flow cross-holes  115 A,  115 B and preclude venting fluid from the first port  112  to the second port  114 . 
     In the actuated position or state shown in  FIG. 3 , the valve  100  operates in a pressure relief mode and can be used to control or limit pressure level in a hydraulic system. Particularly, in the actuated state when the solenoid actuator sleeve  154  is in the second position, the cross-holes  155 A,  155 B become aligned with, or partially overlapping, the annular groove  174  and the cross-holes  172 A,  172 B, respectively. As such, the valve  100  is configured to open a second pilot flow path from the first port  112  to the second port  114  when pressure level of fluid at the first port  112 , which is communicated to the pilot check ball  139  and pilot poppet  138  via the orifice  128 , the main chamber  120 , and the longitudinal channel  132 , reaches a predetermined setting pressure determined by the setting spring  144 . The predetermined setting pressure is determined by dividing a preload force that the setting spring  144  applies to the pilot poppet  138  by the effective area of the pilot seat  136  (e.g., the circular area having the diameter of the pilot seat  136 , which can be slightly larger than the diameter of the longitudinal channel  132 ). 
     Once the pressure level in the main chamber  120  exceeds the predetermined setting pressure, fluid in the main chamber  120  pushes the pilot check ball  139  and the pilot poppet  138  in the proximal direction (to the left in  FIG. 3 ) off the pilot seat  136 . As an example for illustration, the pilot check ball  139  and the pilot poppet  138  can move a distance of about 0.05 inches off the pilot seat  136 . 
     As a result of the pilot check ball  139  and the pilot poppet  138  being unseated, a second pilot flow path is formed and pilot flow is generated from the first port  112  through the orifice  128 , the main chamber  120 , the longitudinal channel  132 , to within the pilot sleeve portion  141  (e.g., the pilot chamber  142 ) then through the cross-hole  172 A,  172 B, the annular groove  174 , the cross-holes  155 A,  155 B, the annular space  166 , the longitudinal through-hole  168 , the annular groove  170 , and the pilot flow cross-hole  116  to the second port  114 . As such, when the valve  100  is actuated, the first pilot flow path that includes the radial channel  134  is blocked; however, when the pressure level exceeds the pressure relief setting of the valve  100 , a second pilot flow path that includes the cross-holes  172 A,  172 B and the annular groove  174  is formed and allows pilot flow therethrough. 
     The pilot flow causes a pressure drop across the orifice  128 , thereby causing the piston  118  to be subjected to a force imbalance and to move in the proximal direction against the main spring  122 . Axial movement of the piston  118  past edges of the main flow cross-holes  115 A,  115 B allows main flow from the first port  112  through the main flow cross-holes  115 A,  115 B to the second port  114 . As such, pressurized fluid at the first port  112  is relieved to the second port  114 , thereby precluding pressure level at the first port  112  from increasing further. 
     The valve  100  can be referred to as a fixed setting pressure relief valve because once the preload of the setting spring  144  is set by the location of the spring preload adjustment screw  148  and the solenoid actuator  106  is installed, the preload of the setting spring  144  and its biasing force cannot be changed without disassembling the valve  100 . In some applications, it may be desirable to have a manual adjustment actuator coupled to the valve so as to allow for manual modification of the preload of the setting spring  144 , and thus modification of the pressure relief setting on the valve, while the valve is installed in the hydraulic system without disassembling the valve. 
       FIG. 4  illustrates a cross-section side view of a valve  400  having a manual adjustment actuator  402 , in accordance with an example implementation. Identical components of both valves  100 ,  400  are designated with the same reference numbers. The valve  400  includes a solenoid tube  404  that differs from the solenoid tube  150  in that the solenoid tube  404  has a two-chamber configuration that allows it to receive the manual adjustment actuator  402 . 
       FIG. 5  illustrates a cross-sectional side view of the solenoid tube  404 , in accordance with an example implementation. As depicted, the solenoid tube  404  has a cylindrical body  500  having therein a first chamber  502  within a distal side of the cylindrical body  500  and a second chamber  504  within a proximal side of the cylindrical body  500 . The solenoid tube  404  includes a pole piece  503  formed as a protrusion from an interior peripheral surface of the cylindrical body  500 . The pole piece  503  separates the first chamber  502  from the second chamber  504 . In other words, the pole piece  503  divides a hollow interior of the cylindrical body  500  into the first chamber  502  and the second chamber  504 . The pole piece  503  can be composed of material of high magnetic permeability. 
     Further, the pole piece  503  defines a channel  505  therethrough. In other words, an interior peripheral surface of the solenoid tube  404  at or through the pole piece  503  forms the channel  505 , which fluidly couples the first chamber  502  to the second chamber  504 . As such, pressurized fluid provided to the first chamber  502  is communicated through the channel  505  to the second chamber  504 . 
     In examples, the channel  505  can be configured to receive a pin therethrough so as to transfer linear motion of one component in the second chamber  504  to another component in the first chamber  502  and vice versa. As such, the channel  505  can include chamfered circumferential surfaces at its ends (e.g., an end leading into the first chamber  502  and another end leading into the second chamber  504 ) to facilitate insertion of such a pin therethrough. 
     The solenoid tube  404  has a distal end  506  configured to be coupled to the housing  108  and a proximal end  508  configured to be coupled to and receive the manual adjustment actuator  402 . Particularly, the solenoid tube  404  can have a first threaded region  510  disposed on an exterior peripheral surface of the cylindrical body  500  at the distal end  506  that is configured to threadedly engage with corresponding threads formed in the interior peripheral surface of the housing  108 . 
     Also, the solenoid tube  404  can have a second threaded region  512  disposed on the exterior peripheral surface of the cylindrical body  500  at the proximal end  508  and configured to be threadedly engage with corresponding threads formed in the interior peripheral surface of the coil nut  153 . Further, the solenoid tube  404  can have a third threaded region  514  disposed on an interior peripheral surface of the cylindrical body  500  at the proximal end  508  and configured to threadedly engage with corresponding threads formed in a component of the manual adjustment actuator  402  as described below. The solenoid tube  404  can also have one or more shoulders formed in the interior peripheral surface of the cylindrical body  500  that can mate with respective shoulders of the manual adjustment actuator  402  to enable alignment of the manual adjustment actuator  402  within the solenoid tube  404 . 
     Referring back to  FIG. 4 , the solenoid tube  404  is configured to house an armature  406  in the first chamber  502 . The armature  406  has a longitudinal channel  408  formed therein. The armature  406  also includes an annular internal groove or T-slot  410  configured to receive the male T-shaped member  200  of the solenoid actuator sleeve  154 . The armature  406  further includes a protrusion  412  from its interior peripheral surface. The solenoid spring  164  is configured to rest on the protrusion  412  to bias the armature  406  in the distal direction. 
     As mentioned above, the solenoid tube  404  includes the pole piece  503  formed as a protrusion from the interior peripheral surface of the solenoid tube  404 . The pole piece  503  is separated from the armature  406  by the airgap  158 . 
     The manual adjustment actuator  402  is configured to allow for adjusting the pressure relief setting of the valve  400  without disassembling the valve  400 . The manual adjustment actuator  402  includes a pin  414  disposed through the channel  505 . The pin  414  is coupled to a spring cap  416  that interfaces with the setting spring  144  of the valve  400 . As such, the valve  400  differs from the valve  100  in that, rather than the setting spring  144  interfacing with the spring preload adjustment screw  148 , which is fixed once screwed to a particular position, the valve  400  includes the spring cap  416 , which is movable via the pin  414  and can adjust the length of the setting spring  144 . 
     The manual adjustment actuator  402  includes an adjustment piston  418  that interfaces with or contacts the pin  414 , such that longitudinal or axial motion of the adjustment piston  418  causes the pin  414  and the spring cap  416  coupled thereto to move axially therewith. The adjustment piston  418  can be threadedly coupled to a nut  420  at threaded region  422 . The nut  420  in turn is threadedly coupled to the solenoid tube  404  at the threaded region  514 . As such, the adjustment piston  418  is coupled to the solenoid tube  404  via the nut  420 . Further, the adjustment piston  418  is threadedly coupled at threaded region  424  to another nut  426 . 
     The adjustment piston  418  is axially movable within the second chamber  504  of the solenoid tube  404 . For instance, the adjustment piston  418  can include an adjustment screw  428 , such that if the adjustment screw  428  is rotated in a first rotational direction (e.g., clockwise) the adjustment piston  418  moves in the distal direction (e.g., to the right in  FIG. 4 ) by engaging more threads of the threaded regions  422 ,  424 . If the adjustment screw  428  is rotated in a second rotational direction (e.g., counter-clockwise) the adjustment piston  418  is allowed to move in the proximal direction (e.g., to the left in  FIG. 4 ) by disengaging some threads of the threaded regions  422 ,  424 . 
     While the distal end of the setting spring  144  is coupled to or rests against the pilot poppet  138 , the proximal end of the setting spring  144  rests against the spring cap  416 , which is coupled to the adjustment piston  418  via the pin  414 . As such, axial motion of the adjustment piston  418  results in a change in the length of the setting spring  144 . As a result, the biasing force that the setting spring  144  exerts on the pilot poppet  138 , and thus the pressure relief setting of the valve  400 , is changed. As such, the pressure relief setting of the valve  400  can be adjusted via the manual adjustment actuator  402  without disassembling the valve  400 . As an example for illustration, the adjustment piston  418  can have a stroke of about 0.15 inches, which corresponds to a pressure relief setting range between 0 psi and 5000 psi. 
     The valve  400  is depicted in  FIG. 4  in the ventable operation mode (similar to the valve  100  in  FIG. 1 ). Similar to the valve  100 , the valve  400  can be switched to the pressure relief mode by energizing the solenoid coil  151  so as to move the armature  406  and the solenoid actuator sleeve  154  in the proximal direction (e.g., to the left in  FIG. 4 ). 
     As a result of the solenoid actuator sleeve  154  moving in the proximal direction, the first pilot flow path through the radial channel  134  is blocked, whereas the annular groove  174  and the cross-holes  172 A,  172 B of the pilot sleeve portion  141  are aligned or partially overlapped with the cross-holes  155 A,  155 B of the solenoid actuator sleeve  154 . The valve  400  is thus switched to the pressure relief mode and can operate similar to the valve  100  as described above with respect to  FIG. 3 . 
     Particularly, the second pilot flow path through the cross-holes  172 A,  172 B and the annular groove  174  is formed when the pressure relief setting is reached at the first port  112  and the pilot check ball  139  is unseated off the pilot seat  136 . As a result of forming or opening the second pilot flow path, pilot flow is allowed therethrough, causing the piston  118  to move and relieving fluid from the first port  112  to the second port  114 . Further, the pressure relief setting of the valve  400  can be adjusted via the manual adjustment actuator  402  to change the pressure level of the fluid at the first port  112  that can overcome the biasing force of the setting spring  144  and unseat the pilot check ball  139  and allow pilot flow to flow from the first port  112  to the second port  114 . 
     The configurations and components shown in  FIGS. 1-5  are examples for illustration, and different configurations and components could be used. For example, components can be integrated into a single component or a component can be divided into multiple components. As another example, different types of springs could be used, and other components could be replaced by components that perform a similar functionality. Further, although the solenoid actuator  106  is shown and described as a pull-type solenoid actuator, in other example implementations the valve  100 ,  400  can be configured such that a push-type solenoid actuator can be used, where the armature  152 ,  406  can be pushed in the distal direction when the solenoid coil  151  is energized. 
     The valves  100 ,  400  can be referred to as ventable pressure relief valves. Particularly, the valve  100  or  400  can be included in hydraulic systems so as to vent the first port  112  to the second port  114  when the valve is unactuated, and switch to a pressure relief mode to build pressure in the hydraulic system and protect the hydraulic system against undesirable increases in pressure level when the valve is actuated. 
       FIG. 6  illustrates a hydraulic system  600  using the valve  400 , in accordance with an example implementation. The valve  400  is depicted symbolically in  FIG. 6 . 
     The hydraulic system  600  includes a source  602  of fluid. The source  602  of fluid can, for example, be a pump configured to provide fluid to the first port  112  of the valve  400 . Such pump can be a fixed displacement pump, a variable displacement pump, or a load-sensing variable displacement pump, as examples. Additionally or alternatively, the source  602  of fluid can be an accumulator or another component (e.g., a valve) of the hydraulic system  600 , such that the source  602  is fluidly coupled to the first port  112  of the valve  400 . 
     As described above, when the valve  400  is unactuated, the first pilot flow path allows pilot flow therethrough and the piston  118  is shifted as shown in  FIG. 4  to allow fluid at the first port  112  to be vented to the second port  114 , which is coupled to a tank  604 . Venting the first port  112  to the second port  114  is symbolized by fluid path  606  as depicted in  FIG. 6 . 
     The hydraulic system  600  can further include a controller  608 . The controller  608  can include one or more processors or microprocessors and may include data storage (e.g., memory, transitory computer-readable medium, non-transitory computer-readable medium, etc.). The data storage may have stored thereon instructions that, when executed by the one or more processors of the controller  608 , cause the controller  608  to perform operations described herein. Signal lines to and from the controller  608  are depicted as dashed lines in  FIG. 6 . The controller  608  can receive input or input information comprising sensor information via signals from various sensors or input devices in the hydraulic system  600 , and in response provide electric signals to various components of the hydraulic system  600 . 
     For instance, the controller  608  can receive a command or input information to switch the valve  400  from operating in a ventable operation mode to a pressure relief mode. The command or input information can be provided to the controller  608  to start building pressure in the hydraulic system  600 . For example, the controller  608  can operate the valve  400  in the ventable operation mode to unload the source  602  until a speed of the engine or motor driving the source  602  reaches a particular value. Once the particular speed value is reached, the controller  608  can switch the valve  400  to the pressure relief mode. In another example, the controller  608  can be configured to operate the valve  400  in the ventable operation mode when the temperature of hydraulic oil exceeds a particular temperature threshold, and switch the valve  400  to the pressure relief mode when the temperature is below the particular temperature threshold. In other examples, the controller  608  can be configured to operate the valve  400  in the ventable operation mode to operate the hydraulic system  600  in a safety mode, and then switch the valve  400  to the pressure relief mode when the hydraulic system  600  is ready to be operational. 
     Thus, in response to the command or input information requesting or indicating the mode switch, the controller  608  can send a command signal to the solenoid coil  151  of the solenoid actuator  106  of the valve  400  to generate a solenoid force on the armature  406 . When the solenoid force overcomes the biasing force of the solenoid spring  164 , the armature  406  and the solenoid actuator sleeve  154  move in the proximal direction as described above. As a result, the first pilot flow path is blocked due to blocking fluid communication from the radial channel  134  to the cross-holes  155 A,  155 B, and the cross-holes  172 A,  172 B and the annular groove  174  are fluidly coupled to the cross-holes  155 A,  155 B, rendering the valve operating in the pressure relief mode. 
     In the pressure relief mode, pressure level of fluid provided by the source  602  is allowed to build up or increase, thus providing pressurized fluid to other portions, components, equipment, or actuators of the hydraulic system  600 . Such other portions, components, equipment, or actuators are represented in  FIG. 6  by block  609 . For example, assuming that the block  609  represents an actuator (e.g., a hydraulic cylinder or motor), pressure level of fluid provided by the source  602  is allowed to increase, and thus pressurized fluid is provided to the actuator and enables the actuator to be operated (e.g., allows a piston of the actuator to extend or retract). 
     If the pressure level of fluid supplied by the source  602  exceeds the pressure setting of the valve  400 , such that pressurized fluid at the first port  112  overcomes the biasing force of the setting spring  144 , pressurized fluid unseats the pilot check ball  139  and the second pilot flow path is opened. Opening the second pilot flow path allows pilot flow, symbolized by arrow  610  in  FIG. 6 , from the first port  112  to the second port  114  through the cross-holes  172 A,  172 B, the annular groove  174 , and the cross-holes  155 A,  155 B. The pilot flow allows the piston  118  to move, thereby allowing main flow from the first port  112  to the second port  114  via the main flow cross-holes  115 A,  115 B and relieving fluid at the first port  112 . The pressure relief mode is represented by symbol  612  in  FIG. 6 . 
     As depicted symbolically in  FIG. 6  by arrow  614 , the biasing force of the setting spring  144  can be adjusted (e.g., via the manual adjustment actuator  402  as described above). The valve  100  can be used in the hydraulic system  600  instead of the valve  400 ; however, the valve  100  can be depicted without the arrow  614 . 
       FIG. 7  is a flowchart of a method  700  for controlling a hydraulic system, in accordance with an example implementation. The method  700  can, for example, be performed by a controller such as the controller  608  to control the hydraulic system  600 . 
     The method  700  may include one or more operations, or actions as illustrated by one or more of blocks  702 - 704 . Although the blocks are illustrated in a sequential order, these blocks may in some instances be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation. 
     In addition, for the method  700  and other processes and operations disclosed herein, the flowchart shows operation of one possible implementation of present examples. In this regard, each block may represent a module, a segment, or a portion of program code, which includes one or more instructions executable by a processor or a controller for implementing specific logical operations or steps in the process. The program code may be stored on any type of computer readable medium or memory, for example, such as a storage device including a disk or hard drive. The computer readable medium may include a non-transitory computer readable medium or memory, for example, such as computer-readable media that stores data for short periods of time like register memory, processor cache and Random Access Memory (RAM). The computer readable medium may also include non-transitory media or memory, such as secondary or persistent long term storage, like read only memory (ROM), optical or magnetic disks, compact-disc read only memory (CD-ROM), for example. The computer readable media may also be any other volatile or non-volatile storage systems. The computer readable medium may be considered a computer readable storage medium, a tangible storage device, or other article of manufacture, for example. In addition, for the method  700  and other processes and operations disclosed herein, one or more blocks in  FIG. 7  may represent circuitry or digital logic that is arranged to perform the specific logical operations in the process. 
     At block  702 , the method  700  includes receiving input information indicating a request to switch the valve  100 ,  400  from operating in a ventable mode to a pressure relief mode. The valve  100 ,  400  is normally operating in the ventable mode as described above with respect to  FIGS. 1 and 4  when the valve  100 ,  400  is unactuated. 
     At block  704 , the method  700  includes, based on the input information, sending a signal to the solenoid coil  151  to switch the valve  100 ,  400  to operate in the pressure relief mode. As described above, the controller  608  can provide a signal to the solenoid coil  151  to cause the armature  152 ,  406  to apply a force on the solenoid actuator sleeve  154  in the proximal direction, such that as the solenoid actuator sleeve  154  moves, the valve  100 ,  400  is switched to operating in the pressure relief mode as described above. 
       FIG. 8  is a flowchart of a method  800  for operating a valve, in accordance with an example implementation. The method  800  shown in  FIG. 8  presents an example of a method that could be used with the valves  100 ,  400 , shown throughout the Figures, for example. The method  800  may include one or more operations, functions, or actions as illustrated by one or more of blocks  802 - 810 . Although the blocks are illustrated in a sequential order, these blocks may also be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation. It should be understood that for this and other processes and methods disclosed herein, flowcharts show functionality and operation of one possible implementation of present examples. Alternative implementations are included within the scope of the examples of the present disclosure in which functions may be executed out of order from that shown or discussed, including substantially concurrent or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art. 
     At block  802 , the method  800  includes operating the valve  100 ,  400  in a ventable mode where the first pilot flow path (e.g., through the radial channel  134  and the cross-holes  155 A,  155 B) is opened to allow pilot flow from the first port  112  to the second port  114 , thereby causing the piston  118  to move (e.g., in the proximal direction) from a first position to a second position and allowing main flow from the first port  112  to the second port  114 . The first position of the piston  118  is a position where the piston  118  can block the main flow cross-holes  115 A,  115 B, and thus block main flow from the first port  112  to the second port  114 . The second position is a position where the piston  118  has moved to expose the main flow cross-holes  115 A,  115 B, and thus allow main flow from the first port  112  to the second port  114  (as depicted in  FIGS. 1 and 4 ). 
     At block  804 , the method  800  includes receiving an electric signal (e.g., from the controller  608 ) energizing the solenoid coil  151  of a solenoid actuator (e.g., the solenoid actuator  106 ) of the valve  100 ,  400 . The controller  608  can receive a request to switch the valve  100 ,  400  to a pressure relief mode. In response, the controller  608  sends the electric signal to the solenoid coil  151  to energize it. 
     At block  806 , the method  800  includes, responsively, causing the armature  152 ,  406  of the solenoid actuator and the solenoid actuator sleeve  154  coupled to the armature  152 ,  406  to move, thereby: (i) blocking the first pilot flow path, (ii) causing the piston  118  to return to the first position and block main flow from the first port  112  to the second port  114 , and (iii) aligning (or fluidly coupling) the cross-holes  155 A,  155 B of the solenoid actuator sleeve  154  with the cross-holes  172 A,  172 B of the pilot sleeve portion  141  of the valve  100 ,  400 . 
     At block  808 , the method  800  includes receiving pressurized fluid having a particular pressure level at the first port  112  of the valve  100 ,  400  such that the pressurized fluid overcomes the biasing force of the setting spring  144  of the valve  100 ,  400 , thereby causing the pilot check member  140  (e.g., the pilot poppet  138  and the pilot check ball  139 ) to be unseated and opening the second pilot flow path via the cross-holes  172 A,  172 B of the pilot sleeve portion  141  of the valve  100 ,  400 , which are aligned with the cross-holes  155 A,  155 B of the solenoid actuator sleeve  154 . 
     At block  810 , the method  800  includes, in response to pilot flow through the second pilot flow path, causing the piston  118  to move, thereby allowing main flow from the first port  112  to the second port  114 . 
     The detailed description above describes various features and operations of the disclosed systems with reference to the accompanying figures. The illustrative implementations described herein are not meant to be limiting. Certain aspects of the disclosed systems can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein. 
     Further, unless context suggests otherwise, the features illustrated in each of the figures may be used in combination with one another. Thus, the figures should be generally viewed as component aspects of one or more overall implementations, with the understanding that not all illustrated features are necessary for each implementation. 
     Additionally, any enumeration of elements, blocks, or steps in this specification or the claims is for purposes of clarity. Thus, such enumeration should not be interpreted to require or imply that these elements, blocks, or steps adhere to a particular arrangement or are carried out in a particular order. 
     Further, devices or systems may be used or configured to perform functions presented in the figures. In some instances, components of the devices and/or systems may be configured to perform the functions such that the components are actually configured and structured (with hardware and/or software) to enable such performance. In other examples, components of the devices and/or systems may be arranged to be adapted to, capable of, or suited for performing the functions, such as when operated in a specific manner. 
     By the term “substantially” or “about” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide. 
     The arrangements described herein are for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g., machines, interfaces, operations, orders, and groupings of operations, etc.) can be used instead, and some elements may be omitted altogether according to the desired results. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location. 
     While various aspects and implementations have been disclosed herein, other aspects and implementations will be apparent to those skilled in the art. The various aspects and implementations disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims, along with the full scope of equivalents to which such claims are entitled. Also, the terminology used herein is for the purpose of describing particular implementations only, and is not intended to be limiting.