MECHANICALLY-OPERABLE OVER-TEMPERATURE SHUTOFF VALVE

Related Applications

This application claims the benefit of U.S. Provisional Application No. 62/823,798 filed March 26, 2019, which is hereby incorporated herein by reference.

Field of Invention

The present invention relates generally to an inerting system with a mechanically-operable valve, and more particularly to aircraft fuel tank inerting systems including an over-temperature shutoff valve that utilizes a shape memory actuator.

Background

Inerting systems are commonly used in aircraft applications to reduce the volatility of the ullage, or air volume above the liquid fuel, in an aircraft fuel tank. Conventional inerting systems include a fluid circuit that receives a flow of supply air, such as bleed air from the aircraft engine, and passes this air through an air separation module for separation into nitrogen-enriched air and oxygen- enriched air. The nitrogen-enriched air portion of the separated air is passed to the fuel tank to enhance the amount of inert air in the ullage.

Prior to entering the air separation module, the supply air is monitored and cooled to below a desired temperature to prevent overly hot air from entering the fuel tank. Conventional inerting systems utilize at least one electronically-controlled over-temperature shutoff valve and one temperature sensor that measures the temperature of the supply air and communicates this measured temperature to a controller. When the controller detects that the temperature of the supply air is greater than an acceptable high-temperature limit, the controller sends a command signal to a solenoid of the electronically- controlled shutoff valve causing the valve to shut off the supply of air to the fuel tank. Summary of Invention

Conventional inerting systems of the type described above may be affected by a high intensity radiated field (HIRF) event, which may cause one or more of the electronic components involved in the over-temperature detection and shutoff function of the system (such as the electronically-controlled shutoff valve, temperature sensor, and/or controller) to malfunction. In addition, such conventional inerting systems typically include two similar electronically- controlled over-temperature shutoff valves and two similar temperature sensors for redundancy in the system, in which due to the design similarities, these are at risk of common mode failures.

The present invention relates to an inerting system that incorporates a mechanically-operable over-temperature shutoff valve that is not susceptible to malfunction due to an HIRF event and/or is not at risk of common mode failures with other shutoff valve(s) in the system.

More particularly, the mechanically-operable shutoff valve includes a shape memory actuator that is configured to sense an over-temperature condition of fluid flowing through the valve and thereby actuate a locking mechanism to deploy a valve member to close the valve in the event of the over temperature event.

Such a shutoff valve may be operable independently of any electronic controller and may provide autonomous over-temperature detection and flow shutoff functionality for the inerting system. In this manner, the shutoff valve may provide a self-contained mechanical means which may be installed in lieu of, or in addition to, an existing electronically-controlled shutoff valve in conventional inerting systems.

According to one aspect of the invention, a valve includes: a valve body having an inlet, an outlet, and a fluid passage extending between the inlet and the outlet; a valve member that is movable in the valve body between an open position, in which the valve member is configured to open the fluid passage for permitting fluid flow therethrough, and a closed position, in which the valve member is configured to close the fluid passage for restricting fluid flow

therethrough; a locking mechanism that is movable relative to the valve body and the valve member, the locking mechanism being configured to hold the valve member in a position relative to the valve body when the locking mechanism is in a locked state; and a shape memory actuator operatively coupled to the locking mechanism and to the valve member; wherein the shape memory actuator is configured to actuate when a temperature of the shape memory actuator reaches or exceeds a predefined temperature, such that actuation of the shape memory actuator causes the locking mechanism to release the valve member thereby enabling the valve member to move relative to the valve body.

According to another aspect of the invention, a valve includes: a spring- biased poppet that is configured to be held in position by a locking mechanism in a normal operating state; and a shape memory actuator operatively coupled to the locking mechanism; wherein the shape memory actuator is configured to deactivate the locking mechanism thereby releasing the poppet when a temperature of the shape memory actuator reaches or exceeds a preset temperature.

According to another aspect of the invention, a method of operating a valve includes: holding a valve member in an open position with a locking mechanism; heating a shape memory material of a shape memory actuator with fluid flowing through the actuator, wherein the shape memory actuator is operatively connected to the valve member and the locking mechanism; when a temperature of the shape memory material reaches or exceeds a predefined temperature, actuating the shape memory actuator thereby causing the locking mechanism to release the valve member; and after actuating the shape memory actuator, moving the valve member to a closed position.

According to another aspect of the invention, a fuel tank inerting system includes: a fluid circuit connected to a fuel tank; an inert-gas generator in the fluid circuit upstream of the fuel tank; and a mechanically-operable over temperature shutoff valve in the fluid circuit upstream of the fuel tank; wherein the over-temperature shutoff valve has a shape memory actuator that is configured to sense a temperature of fluid in the fluid circuit, and wherein when the fluid temperature causes the shape memory actuator to reach or exceed a predefined temperature, the shape memory actuator is configured to activate the shutoff valve to close, thereby restricting fluid flow to the fuel tank. The following description and the annexed drawings set forth certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features according to aspects of the invention will become apparent from the following detailed description when considered in conjunction with the drawings.

Brief Description of the Drawings

The annexed drawings, which are not necessarily to scale, show various aspects of the invention.

Fig. 1 is a schematic view of an exemplary inerting system having an exemplary mechanically-operable over-temperature shutoff valve according to an embodiment of the invention.

Fig. 2 is a schematic view of another exemplary inerting system having the exemplary mechanically-operable over-temperature shutoff valve according to an embodiment of the invention

Fig. 3 is a top plan view of the exemplary mechanically-operable over temperature shutoff valve.

Fig. 4 is a cross-sectional side view of the mechanically-operable over temperature shutoff valve taken about the line 4-4 in Fig. 3, in which the valve is shown in an exemplary locked and open state.

Fig. 5 is a cross-sectional top view of the mechanically-operable over temperature shutoff valve taken about the line 5-5 in Fig. 4, in which the valve is shown in the exemplary locked and open state.

Fig. 6A is a perspective view of an exemplary locking sleeve of the mechanically-operable over-temperature shutoff valve.

Fig. 6B is a front view of the locking sleeve.

Fig. 6C is a side view of the locking sleeve.

Fig. 6D is a top view of the locking sleeve.

Fig. 6E is a cross-sectional top view of the locking sleeve taken about the line 6E-6E in Fig. 6C.

Fig. 6F is a cross-sectional side view of the locking sleeve taken about the line 6F-6F in Fig. 6D. Fig. 7 is a cross-sectional side view of the mechanically-operable over temperature shutoff valve from Fig. 4, now shown in an exemplary released and closed state.

Detailed Description

The principles and aspects of the present invention have particular application to fuel tank inerting systems for aircraft applications, and thus will be described below chiefly in this context. It is understood, however, that the principles and aspects of this invention may be applicable to other systems in which it is desirable to provide a mechanically-operable valve that is configured to actuate by sensing the temperature of fluid flowing through the valve, and more particularly such a valve that utilizes a shape memory actuator that actuates at a predefined temperature.

Referring to Fig. 1 , an exemplary fuel tank inerting system 100 is shown. Generally, the inerting system 100 includes a fluid circuit 102 that receives a flow of supply gas, such as bleed air from an aircraft engine, and passes this supply gas through an air separation module 104 to separate the supply gas into nitrogen-enriched air (NEA) and oxygen-enriched air (OEA). The nitrogen- enriched air portion of the separated gas is passed to the fuel tank 106 to enhance the amount of inert air in the ullage. The system 100 also includes a supply gas cooling system 108 and one or more temperature monitoring and shutoff control systems 110, 112 that are configured to prevent overly hot air from entering the fuel tank 106, as discussed below.

In exemplary embodiments, the fluid circuit 102 of the inerting system 100 includes an inlet 114 that is fluidly connected to a source of the supply gas, such as the bleed air from the aircraft engine. The fluid circuit 102 may be formed by one or more fluid passages, conduits, or other suitable structures in a well- known manner. As shown, after the supply gas enters through the inlet 114, the supply gas is passed through the cooling system 108, which includes a chiller 116 that is configured to cool the supply gas at an upstream portion of the fluid circuit 102. The chiller 116 may include a heat exchanger through which the supply gas flows, and cooling air may flow over the heat exchanger to cool the supply gas flowing through the heat exchanger. The cooling system 108 also includes a temperature control device 118 which co-operates with the chiller 116 and is operably coupled to a controller 120 to regulate the temperature of the fluid exiting the chiller 116. The temperature control device 118 may be a motor operated butterfly valve, for example.

As shown, a filter 122, such as a paper filter, may be provided

downstream of the cooling system 108 for removing particulate matter from the supply gas prior to the gas entering the air separation module (ASM) 104.

The air separation module 104 is located in the fluid circuit 102

downstream of the cooling system 108 and upstream of an outlet 124 of the fluid circuit 102 that is fluidly connected to an inlet of the fuel tank 106. In a known- manner, the air separation module 104 may include a separation medium, such as a hollow-fiber membrane, or any other known medium or apparatus that is configured to separate the supply gas into nitrogen-enriched air and oxygen- enriched air. Essentially, the air separation module 104 may include any device that performs the function of separating nitrogen-enriched air from supply air. In this manner, the air separation module 104 is one exemplary form of an inert-gas generator that generates nitrogen-enriched air from the supply air. As shown, the oxygen-enriched air (OEA) may be discarded, and the nitrogen-enriched air (NEA) may pass downstream through the outlet 124 and into the ullage of the fuel tank 106 to enhance the amount of inert gas in the ullage to reduce volatility. It is understood that other embodiments may include different configurations of the inerting system which may utilize other forms of inert-gas generators, such as pressure swing adsorption systems or catalytic inerting systems.

In the illustrated embodiment, the inerting system 100 includes two temperature monitoring and shutoff control systems 110, 112, including a primary shutoff control system 110 and a secondary shutoff control system 112. Each of the shutoff control systems 110, 112 are configured to prevent the supply gas from flowing downstream to the air separation module 104 and/or the fuel tank 106 in the event that an over-temperature condition of the supply gas is determined by the system(s) 110, 112. The primary shutoff system 110 includes an electronically-controlled shutoff valve 126, such as a pilot-operated solenoid valve, that is operably coupled to the controller 120 to receive command signals to open or close the valve 126. The primary shutoff valve system 110 also includes a temperature sensor 128, such as a device that operates based on an RTD (resistance temperature detector) sensing element, or any other suitable device, that measures the temperature of the supply gas (e.g., downstream of the chiller 116) and communicates the measured temperature to the controller 120. When the controller 120 detects that the measured temperature of the supply gas is greater than an acceptable high-temperature limit, the controller 120 sends a command signal to the electronically-controlled (e.g., solenoid) valve 126 causing the valve to close and shutoff the supply of gas downstream to the fuel tank 106. It is understood that the inerting system 100 can also be configured such that the controller 120 sends command signals to shutoff both electronically-controlled valves 126, 130 for redundancy when it detects the greater than acceptable high-temperature limit.

In the illustrated embodiment, the secondary shutoff system 112 has a nearly identical construction to that of the primary shutoff system 110 and is utilized for redundancy in the inerting system 100. As shown, the secondary shutoff system 112 has an electronically-controlled shutoff valve 130 that is fluidly connected in the fluid circuit 102 downstream of the filter 122 and includes a temperature sensor 132 configured to sense temperature of the fluid upstream of the air separation module 104. The dissimilarities in the two electronically- controlled shutoff valve systems 110, 112 are primarily due to the physical design peculiarities in the two electronically-controlled shutoff valves 126, 130 and the base resistance value difference in the two temperature sensors 128, 132. These dissimilarities are intentionally built into the inerting system design to reduce the risk of common mode failures.

As shown in Fig. 1 , the exemplary fuel tank inerting system 100 also includes an exemplary mechanically-operable valve 10. In exemplary

embodiments, the mechanically-operable valve 10 is a mechanically-operable over-temperature shutoff valve (MOTSOV) that may be operable independently of any electronic controller and may provide autonomous over-temperature detection and flow shutoff functionality for the inerting system 100. More particularly, as discussed in further detail below, the mechanically-operable shutoff valve 10 includes a shape memory actuator that is configured to sense an over-temperature condition of the fluid flowing through the valve and thereby actuates a locking mechanism to deploy a valve member to close the valve during the over-temperature event.

In the illustrated embodiment, the MOTSOV 10 is installed in the fluid circuit 102 downstream of the secondary shutoff system 112 and upstream of the ASM 104 and/or the outlet 124 of the fluid circuit 102 (e.g., upstream of the fuel tank 106). In this manner, the MOTSOV 10 serves as a backup to the primary and/or secondary electronically-controlled valves 126, 130 to shut off the supply of gas to the fuel tank 106 in the event of an over-temperature condition. It is understood, however, that other configurations of the inerting system 100 may be employed, such that the MOTSOV 10 may be located in other portions of the fluid circuit 102 upstream of the outlet 124 to the fuel tank 106, as may be desirable for particular applications.

One problem addressed by the exemplary mechanically-operable over temperature shutoff valve 10 is that, unlike the electronically-controlled shutoff systems 110, 112, the MOTSOV 10 is not susceptible to malfunction due to high- intensity radiated field (HIRF) effects.

The electromagnetic HIRF environment exists because of the

transmission of electromagnetic RF energy from radar, radio, television, and other ground-based, shipborne, or airborne RF transmitters. Aircraft flying near these transmission sources may be subject to HIRF. HIRF can affect any electronic and digital systems onboard the aircraft, causing affected systems to operate erratically. The environment inside a microwave oven while in operation is one extreme example of an HIRF environment.

For example, a single HIRF event may cause multiple inerting

components involved in the over-temperature detection and shutdown function (e.g., temperature sensors 128, 132, valves 126, 130, and/or controller 120) to temporarily or permanently malfunction so as to prevent the valves 126, 130 from shutting off as they should when an actual over-temperature event occurs.

It is also conceivable that an HIRF event could inadvertently drive the closed shutoff valves 126, 130 to open when they are supposed to remain closed to block downstream flow of over-temperature air. The exemplary mechanically- operable over-temperature shutoff valve 10, on the other hand, may operate autonomously without any interaction with any controller (neither that of the inerting system 100 nor of the aircraft) and thus provides the inerting system 100 a degree of immunity from possible loss of over-temperature shutoff functionality due to an HIRF event affecting the primary and/or secondary valves 126, 130.

Another problem addressed by providing the exemplary mechanically- operable over-temperature shutoff valve 10 in the inerting system 100 is that the valve 10 operates under a different principle than the electronically-controlled valve systems 110, 112, which helps to minimize the possibility of a common mode failure. For example, the temperature sensors 128, 132 of the primary and secondary valve systems 110, 112 may be identical in their operating principles. Both sensors 128, 132 may employ the same temperature sensing technology and have similar electrical properties and operating characteristics. The two valves 126, 130 also may be identical in their operating principles. For example, both electronically-controlled shutoff valves 126, 130 may be pilot operated by a solenoid, such that both valves 126, 130 have similar electrical properties and mechanical makeup. Because of these similarities, any weaknesses of operation due to the shared design concept and/or common manufacturing in the similar parts which make up the temperature sensors 128, 132 and/or the valves 126, 130 could cause a common mode failure in the sensors 128, 132 and/or valves 126, 130, thereby negating the redundancy assumptions made in the inerting system architecture. The controller 120, which may have two parts that are configured to operate the two electronically-controlled valves 126, 130, also may be subject to common mode failures due to similar components used.

Accordingly, providing the exemplary mechanically-operable over-temperature shutoff valve 10 provides another layer of redundancy for over-temperature detection and flow shutoff functionality in the event of a common mode failure of the primary and secondary valves 126, 130, the primary and secondary temperature sensors, 128, 132, and/or the two parts of the controller 120.

Turning to Fig. 2, another exemplary embodiment of a fuel tank inerting system 200 is shown. The inerting system 200 is substantially similar to the above-referenced inerting system 100, and consequently the same reference numerals but indexed by 100 are used to denote structures corresponding to the same or similar structures in the inerting systems 100, 200. In addition, the foregoing description of the inerting system 100 is equally applicable to the inerting system 200, except as noted below. Moreover, aspects of the inerting systems 100, 200 may be substituted for one another or used in conjunction with one another where applicable.

As shown in the illustrated embodiment, the inerting system 200 is substantially similar to the inerting system 100, except that the MOTSOV 10 replaces the secondary shutoff valve 130. In this manner, the inerting system 200 utilizes the primary shutoff system 210 for over-temperature detection and flow shutoff function, and the MOTSOV 10 serves as the secondary shutoff system 212 for over-temperature detection and flow shutoff function in the system 200. The MOTSOV 10 may be significantly smaller than the

electronically-controlled valve 130, such that elimination of the electronically- controlled valve 130 and other shutoff system components (e.g., temperature sensor 132) may result in a significant size and weight savings for this inerting system 200.

Referring particularly to Figs. 3-5 and 7, an exemplary embodiment of the mechanically-operable valve 10 is shown. Generally, the valve 10 includes a valve body 12, a valve member 14 that is movable in the valve body 12, a locking mechanism 16 that is configured to hold the valve member 14 in a position relative to the valve body 12, and a shape memory actuator 18 that is configured to actuate the locking mechanism 16 to thereby release the valve member 14 when a temperature of the shape memory actuator 18 reaches or exceeds a preset temperature, as will be discussed in further detail below.

The valve body 12 includes an inlet 21 , an outlet 20, and a fluid passage 22 extending between the inlet 21 and the outlet 20. In exemplary embodiments, the valve body 12 extends along a longitudinal axis 23 and has a generally cylindrical construction. As shown, the valve body 12 includes a first connector 25 toward the inlet 21 side of the valve body 12, and a second connector 24 toward the opposite outlet 20 side of the valve body 12, which are utilized for connecting the valve 10 in a fluid circuit, such as the exemplary fluid circuit(s) 102, 202 of the inerting system(s) 100, 200. As shown in the illustrated embodiment, the valve body 12 may have a multi-piece construction, in which an inlet portion 27 of the valve body 12 is coupled to an outlet portion 26 of the valve body 12, such as via threads or any other suitable coupling. A seal 28, such as an O-ring seal, may be provided at the connection between the inlet portion 27 and outlet portion 26 of the valve body 12. The multi-piece

construction of the valve body 12 may facilitate assembly of the components within the valve body 12. However, it is understood that the valve body 12 also could be a unitary construction, as would be understood by those having ordinary skill in the art.

The valve member 14 is disposed within the valve body 12 and is slidably movable along the longitudinal axis 23 between an open position for allowing fluid flow through the valve body 12 (as shown in Fig. 4, for example), and a closed position for closing the fluid flow path through the valve body 12 (as shown in Fig. 7, for example). The valve member 14 may be any suitable type of valve member that is configured to move toward and away from a valve seat 30 in the valve 10 for opening or closing the fluid flow path through the valve body 12. In the illustrated embodiment, for example, the valve member 14 is configured as a poppet having a head portion 32 with a sealing surface 33 that is configured to sealingly engage the valve seat 30 formed by an inner surface of the valve body 12. As shown, the sealing surface 33 may include a molded elastomeric seal on the head portion 32 of the valve member 14.

In exemplary embodiments, the valve member 14 has a hollow main body portion 34 with radially inward surfaces that define an internal chamber 36. The internal chamber 36 opens toward the inlet end 21 of the valve 10, and thus forms a portion of the fluid passage 22 through which fluid flows from the inlet 21 to the outlet 20 of the valve body 12 (or vice versa, as shown with the directional flow arrows F). As shown, the valve member 14 includes a plurality of

circumferentially spaced orifices 38 that extend radially through the body portion 34 of the valve member 14, which enable fluid to flow through the internal chamber 36 and across the orifices 38 toward the outlet 20 (or vice versa) when the valve member 14 is in the open position. The orifices 38 are located at an intermediate portion 40 of the valve member 14 in front of the sealing surface 33 of the valve member 14, such that when the valve member 14 is in the closed position, the sealing surface 33 of the valve member 14 engages the valve seat 30 and prevents fluid flow through the body portion 34 via the orifices 38 of the valve member 14. Also as shown in the illustrated embodiment, the valve member 14 may include an axially rearward portion 42, such as an extension 42 or tail portion, that extends axially rearward of the head portion 32. The rearward extension 42 may be configured to attach to a portion of the shape memory actuator 18, as discussed in further detail below.

The valve 10 also includes a biasing member 44 for the valve member 14 that is configured to engage and urge the valve member 14. In the illustrated embodiment, the biasing member 44 is a spring that is disposed in a spring chamber 46, which is formed as an annular gap between the inlet and outlet portions 27, 26 of the valve body 12. As shown in the illustrated embodiment, the biasing member 44 is interposed between a radial shoulder 48 of the valve member 14 and shoulder 49 the valve body 12. In this manner, the biasing member 44 is configured to urge the valve member 14 toward the closed position (as shown in Fig. 7, for example) as will be discussed in further detail below.

The locking mechanism 16 is configured to move between a locked state for holding the valve member 14 in position relative to the valve body 12, and a release state for releasing the valve member 14 thereby enabling the valve member 14 to move relative to the valve body 12. In exemplary embodiments, the locking mechanism 16 is movable relative to both the valve member 14 and the valve body 12 and may be any suitable locking mechanism for effecting the hold or release of the valve member 14 in the valve 10. In the illustrated embodiment, for example, the locking mechanism 16 includes an axially movable locking sleeve 50 that cooperates with one or more radially movable locking elements 52. Generally, when the locking sleeve 50 is moved axially to its locked position (as shown in Fig. 4, for example), each locking element 52 is configured to move radially to its locked position to engage the valve body 12 and valve member 14, and to interfere with the relative axial movement between valve body 12 and valve member 14, thereby holding the valve member 14 in position. On the other hand, when the locking sleeve 50 is moved to its release position (as shown in Fig. 7, for example), each locking element 52 is configured to move radially to its release position to disengage from the valve body 12 and/or the valve member 14 to permit relative axial movement between the valve body 12 and valve member 14, thereby enabling the valve member 14 to move within the valve body 12.

In the illustrated embodiment, the one or more locking elements 52 include one or more locking balls (also referred to with reference numeral 52) that cooperate with the locking sleeve 50 to cause the ball(s) 52 to protrude into or retract from (a) circumferential groove(s) 54 in the valve body 12. As shown in the illustrated embodiment, the locking sleeve 50 is movable along the longitudinal axis 23 to slide within the internal chamber 36 of the valve member 14. When the locking sleeve 50 is in its locked position (Fig. 4, for example), an outer surface 55 of the locking sleeve 50 supports the locking ball(s) 52 at a radially outward position such that the locking ball(s) 52 protrude through aperture(s) 56 in the body 34 of the valve member 14 and into the locking groove 54 of the valve body 12, thereby causing an interference that holds the valve member 14 relative to the valve body 12. On the other hand, when the locking sleeve 50 is in its release position (Fig. 7, for example), the locking ball(s) 52 retract radially inwardly into a circumferential groove 58 of the locking sleeve 50 such that the locking ball(s) 52 disengage from the locking groove 54 in the valve body 12, thereby releasing the valve member 14 by enabling axial movement of valve member 14 relative to valve body 12.

As shown, the valve 10 further includes a biasing member 60 for biasing the locking sleeve 50. In the illustrated embodiment, the biasing member 60 is a spring that is disposed within a spring chamber 61 that is formed as an annular gap between an axially rearward end portion 62 of the locking sleeve 50 and the main body portion 34 of the valve member 14. The biasing member 60, being interposed between the locking sleeve 50 and the valve member 14 in the illustrated embodiment, is configured to urge the locking sleeve 50 to axially extend relative to the valve member 14 (e.g., telescopically extend from the internal chamber 36) such that the locking sleeve 50, and thereby the locking element(s) 52, are urged toward their respective locked positions. As discussed in further detail below, the biasing member 60 for the locking sleeve 50 is configured to cooperate with the shape memory actuator 18 so that the force exerted by the shape memory actuator 18 when actuated is sufficient to overcome the biasing force generated by the biasing member 60, thereby allowing the locking sleeve 50 to move to its release position.

Referring to Figs. 6A-6F, the exemplary locking sleeve 50 is shown in further detail. As shown, the locking sleeve 50 has a generally cylindrical main body 63 that extends along a longitudinal axis between a forward end portion 64 and a rearward end portion 62. The forward end portion 64 includes an inlet opening 66, and the rearward end portion 62 includes an outlet opening 65 for allowing fluid flow entering inlet 21 to flow through the inside of the locking sleeve 50, then through the orifices 38 of the valve member 14 and exit the outlet 20 of the valve 10. In exemplary embodiments, the rearward end portion

62 has a reduced diameter that is configured to cooperate with radially inward surfaces of the valve member 14 to form the spring chamber 61 for containing the biasing member 60. As shown, an intermediate portion 67 of the main body

63 provides an abutment 68 for engaging the biasing member 60, and also includes the circumferential groove 58 that receives the locking element(s) 52 when the locking sleeve 50 is in its release position.

As shown in Figs. 6A-6F, the forward end portion 64 of the locking sleeve 50 may include one or more axially extending notches 69 that are configured to receive a pin 70 or other suitable abutment for restricting movement of the locking sleeve 50 beyond the pin 70. As shown in Fig. 4, for example, the pin 70 is supported by the valve member 14 and allows linear movement of the locking sleeve 50 relative to the valve member 14, but restricts the locking sleeve 50 from extending away from the valve member 14 when the pin 70 is received within the notches 69 of the locking sleeve 50. In exemplary embodiments, the forward end portion 64 of the locking sleeve 50 also includes an axially forward portion 71 , such as an extension 71 or bridge portion, that extends axially forward toward the inlet 21 of the valve body 12. The axially forward extension 71 of the locking sleeve 50 may be configured to attach to a portion of the shape memory actuator 18, as discussed in further detail below.

Referring again particularly to Figs. 4 and 5, the shape memory actuator 18 is shown operatively coupled to the locking mechanism 16 and the valve member 14, and the shape memory actuator 18 is configured to move the locking mechanism 16 to its release position when the shape memory actuator 18 is actuated. The shape memory actuator 18 may be any suitable actuator that includes a shape memory material that is configured to change shape, and thereby actuate, when a temperature of the shape memory material reaches or exceeds a predefined temperature. In exemplary embodiments, the shape memory actuator 18 includes a heat sensing portion 72 in thermal

communication with the fluid flowing through the valve. In the illustrated embodiment, for example, the heat sensing portion 72 of the shape memory actuator is disposed in the fluid flow path of the valve body 12 and/or fluid circuit 102, in which this heat sensing portion 72 is configured to sense the temperature of the fluid. When the shape memory material of the actuator 18 is heated by the fluid via the heat sensing portion 72 to the predefined transition temperature of the material, or above, the shape memory material will change shape, thereby actuating the shape memory actuator 18 and causing the locking mechanism 16 to move to its release state, which releases the valve member 14.

Generally, shape memory materials have a current form (shape), and a stored permanent form (shape). Once the stored permanent (memory) form has been set, the current (temporary, non-memory) form may be changed by a process of deforming the material while below the material’s transition

temperature. Optionally, some shape memory materials may change the current (temporary) form by heating the material, deforming the material, and then cooling. The shape memory material will then maintain that current (temporary) form until the material is heated sufficiently (e.g., at or beyond the material’s transition temperature) to cause it to return to its permanent (memory) form, unless otherwise constrained. Because of the clear and decisive nature in which a shape change occurs with shape memory materials, and the predictive manner in which the mechanical properties change, such shape memory materials may be particularly useful for the temperature sensing and actuating of the

mechanically-operable valve 10, such as when used as an over-temperature shutoff valve in the exemplary inerting system(s) 100, 200 described above.

In exemplary embodiments, the shape memory material of the actuator 18 includes a shape memory alloy material that responds to a temperature change by transitioning from one phase (e.g.,. Martensite) to another phase (e.g., Austenite) at a precise transition temperature. In such shape memory alloy materials, the Martensitic phase of the material typically corresponds to the temporary form of the material, and the transformation to Austenite at the transformation temperature corresponds to the permanent form of the material.

It is understood, however, that other shape memory materials may be utilized, such as shape memory polymer materials, as would be understood by those having ordinary skill in the art.

In exemplary embodiments, the shape memory alloy material of the actuator 18 is made of Nitinol (a nickel-titanium alloy composed of roughly equal atomic percentages). Nitinol is a commercially-available and commonly used form of shape memory alloy, which is available in various forms (wire, bar, sheet, etc.) by several manufacturers, such as Dynalloy (Irvine, CA), Memry (Bethel, CT), and Toki Biometal (Tokyo, Japan). As discussed above, a notable characteristic of Nitinol as a shape memory alloy material is the ability of the material to be deformed to a temporary shape when cold, and to restore to its permanent (memory) shape when the material is heated to above its phase transition temperature. Nitinol alloys can be made to have a phase transition temperature anywhere between -10°C to 100°C, or greater. However, most commonly available Nitinol alloys are configured to have their transition temperature at 70°C or 90°C, or any temperature in the range therebetween. Below the phase transition temperature (Martensitic phase), the alloy has a low yield strength and can be easily deformed into any shape. At or above the phase transition temperature (Austenitic phase), however, the alloy restores to its original (memory) shape and behaves super-elastically.

In exemplary embodiments, the shape memory actuator 18 is operatively coupled to both the locking sleeve 50 and the valve member 14 to allow the locking sleeve 50 to extend away from or to cause it to retract toward the valve member 14 depending on the configuration of the shape memory actuator 18. For example, the shape memory material of the actuator 18 may be configured to have its permanent (memory) shape correspond to the release state of the valve 10 (as shown in Fig. 7, for example), and its temporary shape correspond to the locked state of the valve 10 (as shown in Fig. 4, for example). More particularly, in the illustrated embodiment, when the shape memory material of the actuator 18 is in its temporary shape, it yields to the force exerted by the biasing member 60 and allows the locking sleeve 50 to extend from the internal chamber 36 of the valve member 14 to support the locking elements 52 in the locked state to hold the valve member 14 in position. When the shape memory material of the actuator 18 is heated via the fluid flowing through the valve 10 to the material’s predefined transition temperature, the shape memory material will have a shape memory force that tends to cause the shape memory material to reconfigure toward its permanent shape, thereby causing the locking sleeve 50 to retract into the internal chamber 36 with the locking elements 52 retracting to the release state of the locking mechanism 16, thereby permitting movement of the valve member 14.

In the illustrated embodiment, the shape memory actuator 18 is formed by a wire that is made of the shape memory material. As shown, the wire (also referred to as the actuator wire 18) is connected to the axially rearward

extension 42 of the valve member 14 on one side of the actuator wire 18, and to the axially forward extension 71 of the locking sleeve 50 on the other side of the actuator wire 18. More particularly, the axial end portions 74, 75 of the actuator wire 18 may be coupled to the locking sleeve 50 and the valve member 14, such that at least a majority, and preferably the entirety, of the shape memory material (and/or the heat sensing portion 72) is exposed to the fluid flow path in the valve body 12. As shown in the illustrated embodiment, the shape memory material may constitute at least a majority, and preferably the entirety of the actuator wire 18, such that most or all of the wire 18 is in the fluid flow path. Such

configuration provides more uniform heating of the shape memory material of the actuator 18. The configuration of the actuator wire 18 stretched linearly between the valve member 14 and the locking sleeve 50 also may provide a more predictable shape change and shape memory force for actuating the actuator 18 when heated beyond the transition temperature.

Referring particularly to Figs. 4 and 7, an exemplary method of operating the valve 10 will now be described in further detail. In the illustrated

embodiment, when the valve 10 is assembled with the actuator wire 18 installed for a normal operating condition of the valve 10, the actuator wire 18 is stretched in tension between the axially forward extension 71 of the locking sleeve 50 and the axially rearward extension 42 of the valve member 14 (as shown in Fig. 4). The actuator wire 18 may be connected to the locking sleeve 50 and the valve member 14 by any suitable means, such as fastening, adhering, welding, swaging, or the like. In the illustrated embodiment, for example, the actuator wire 18 is attached with one of its axial end portions 75 extending through an aperture 76 in the axially forward extension 71 of the locking sleeve 50 (shown in Fig. 6A and 6E, for example), and the other axial end portion 74 of the actuator wire 18 extending through an aperture 78 in the axially rearward extension 42 of the valve member 14. Each of the exposed end portions 75, 74 are received into respective crimp sleeves 77, 79 which are then mechanically deformed

(crimped) to secure the actuator wire 18 in its predetermined position with respect to the locking sleeve 50 and valve member 14. The process of crimping which involves mechanical joining of two or more items by use of metal deformation is well known in the art.

As shown in Fig. 4, when the actuator wire 18 is stretched in tension, the locking sleeve 50 extends relative to the valve member 14 to its locked position. The biasing member 60 of the locking sleeve 50 is biased toward extending the locking sleeve 50 away from the valve member 14, thereby holding the actuator wire 18 in tension. As discussed above, in the illustrated locked state, the locking sleeve 50 supports the locking elements 52 in the radially outward position to protrude through the apertures 56 in the valve member 14 and into the locking groove54 of the valve body 12, thereby interfering with the relative movement between the valve member 14 and valve body 12. This holds the valve member 14 in its open position in the normal operating state, such as to allow fluid to flow through the valve 10 and into the air separation module 104, 204 and/or fuel tank 106, 206 when used in the inerting systems 100, 200, for example.

In the illustrated embodiment, the actuator wire 18 is made of shape memory alloy material, such as Nitinol, and when stretched to provide a normal operating (e.g. open) state of the valve 10, the actuator wire 18 is in its temporary shape and has a Martensitic phase. When the temperature of the fluid passing through the fluid passage 22 of the opened valve 10 increases, the fluid heats the actuator wire 18 that is disposed within the fluid passage 22.

When the actuator wire 18 is heated via the fluid to its transition temperature or above, the actuator wire 18 transforms from the Martensitic phase to the

Austenitic phase, which causes the actuator wire 18 to return to its permanent (memory) shape, which in the illustrated embodiment causes shortening of the actuator wire 18.

As shown in Fig. 7, when the actuator wire 18 is actuated by heating via the temperature of the fluid to shorten the actuator wire 18 to its permanent (memory) shape, the shape memory force of the actuator wire 18 is greater than the biasing force of the biasing member 60 of the locking sleeve 50, which causes the locking sleeve 50 to retract into the internal chamber 36 of the valve member 14. When the locking sleeve 50 is retracted into the internal chamber 36 to its release position, the locking elements 52 are urged into the recessed groove 58 of the locking sleeve 50, thereby disengaging the locking elements 52 from the locking groove 54 in the valve body 12 and releasing the valve member 14. When the valve member 14 is released, the biasing member 44 of the valve member 14 urges the valve member 14 to engage the valve seat 30, thereby closing the valve 10. In this manner, the shutoff functionality of the valve 10 is automatically activated by actuation of the shape memory actuator 18 by heating the actuator wire 18 to its predefined transition temperature, or above, via the increasing temperature of the fluid.

In one non-limiting example, the actuator wire 18 is made of Nitinol and is approximately 3 inches in length with a diameter of .015 inches. When the actuator wire 18 is installed pre-loaded (stretched) to 3% strain, the wire 18 will be installed pre-stretched using 1.77 pounds of force which is less than the biasing force provided by the biasing member 60 of the locking sleeve. When heated to above the phase-shift transition temperature (e.g., 90°C, for example), the actuator wire 18 will contract and generate the shape memory force. For example, the actuator wire 18 will restore to the original length by contracting 0.09 inches (3 inches x 3% strain) and in so doing will generate about 4.42 pounds of force, which is greater than the biasing force (e.g., spring force) provided by the biasing member 60 of the locking sleeve 50.

In exemplary embodiments, after the valve 10 has been actuated due to a high-temperature event, resetting of the valve 10 back to its normal operating condition will require a maintenance action. To restore the valve 10 into the normal operating state, the valve 10 may be removed from the system (e.g., inerting system 100) and the valve member 14 pushed toward the open position against the biasing force of the valve biasing member 44 until the locking mechanism 16 activates the locked state to hold the valve member 14 in the open position. In such an embodiment, the shape memory material of the actuator 18 may have a one-way memory effect, such that after the shape memory material cools after being heated to its transition temperature, the shape memory material remains in its permanent shape until deformed again.

An exemplary fuel tank inerting system 100, 200 and an exemplary mechanically-operable valve 10 have been disclosed herein. As discussed above, the inerting system that incorporates the self-contained mechanically- operated valve 10 may operate independently of any electronic controller to provide autonomous over-temperature detection and flow shutoff functionality. The mechanically-operable valve 10 also may provide the inerting system immunity to losing shutoff functionality due to a common mode failure or a high- intensity radiated field (HIRF) effect.

In exemplary embodiments, the mechanically-operable valve 10 may be installed in lieu of or in addition to an existing secondary electronically-controlled shutoff valve in a fuel tank inerting system. The mechanically-operable valve 10 may employ a shape memory material, such as a shape memory alloy, for over temperature sensing and actuating of its locking mechanism 16 to release the valve member 14 in the event of the over-temperature event, as discussed above. In exemplary embodiments, the shutoff valve 10 in its normal operating state will only be shut off by an actual occurrence of an over-temperature event, such that no external tampering or unauthorized manipulation from outside of the valve 10 can lead to the valve shutting off inadvertently. This helps to prevent any unauthorized disabling of the inerting system.

Several advantages of the exemplary inerting system 100, 200 and/or the exemplary valve 10 described herein include, but are not limited to, one or more of the following:

Size and Weight Advantage - The exemplary mechanically-operable shutoff valve may be significantly smaller and lighter than existing electronically- controlled (e.g., pilot operated solenoid) shutoff valves. When the MOTSOV replaces such an electronically-controlled shutoff valve, there can be significant weight and space savings for the inerting system. When the MOTSOV is added in addition to the secondary shutoff valve, the addition may have very low weight and space impact.

Stand Alone Operation - The MOTSOV may provide a stand-alone over temperature detection and shutoff functionality to the inerting system, in which the MOTSOV does not require interfacing with a controller, temperature sensor(s), and/or the electronically-controlled valve(s) of the inerting system to operate.

Immune to Common Mode Failures - Possibility of a loss of over temperature detection and shutoff functionality due to a common mode failure may be alleviated in an inerting system that incorporates the MOTSOV. The MOTSOV may operate on an entirely different temperature sensing technology, and its valve mechanisms significantly differ from those of existing electronically- controlled shutoff valves.

Immune to HIRF - Possibility of a loss of over-temperature detection and shutoff functionality due to a H IRF event may be alleviated in an inerting system that incorporates the MOTSOV. This is because the MOTSOV may be entirely mechanical in nature which makes it impervious to H IRF or any other

electromagnetic effects.

Higher Reliability - The MOTSOV may have higher reliability than the overall reliability achievable by a temperature shutoff system that includes a temperature sensor, controller, and an electronically-controlled shutoff valve.

Low Cost - An inerting system that incorporates the MOTSOV may be lower in cost than a conventional inerting system incorporating more than one electronically-controlled shutoff valves due to a simpler construction and ease of manufacturing of the MOTSOV.

Testability - The functionality of the MOTSOV may be tested by using a heat gun to create a simulated over-temperature condition to test the valve for its over-temperature shutoff response. Alternately, an abbreviated form of test may be conducted by manually triggering the valve to shut off by pushing the locking sleeve toward its release position. While exemplary forms of the inerting system 100, 200 and/or

mechanically-operable valve 10 have been described above, it should be apparent to those having ordinary skill in the art that alternative configurations also could be employed. For example, although the valve 10 has been described above as a shutoff valve that is opened in a normal operating condition and then is caused to close when the shape memory actuator is actuated by an over-temperature event, the valve 10 could be constructed as a bypass valve, for example, that is closed in its normal operating position and is actuated to open during an over-temperature event. Alternatively or additionally, the valve 10 may be constructed such that the shape memory material of the actuator 18 has its temporary shape corresponding to the release state of the locking mechanism 16, and the permanent shape corresponding to the locked state of the locking mechanism 16. The shape memory actuator 18 of the valve 10 may provide linear actuation as described above, or the actuator may provide rotational or pivotable actuation, or the like. In addition, the shape memory actuator 18 of the valve may have a shape memory material with a one-way or two-way shape memory effect.

It is also understood that exemplary embodiments may include different configurations of the inerting system which may utilize other forms of inert-gas generators other than an air separation module, such as pressure swing adsorption systems or catalytic inerting systems. In a catalytic inerting system, for example, ullage gas is drawn from the fuel tank, reacts the gas stream in a catalytic converter, cools the gas stream, removes the water, and returns the inert products of the reaction back to the fuel tank without the need for bleed air or attachment to the aircraft pneumatic system. Such a recirculating catalytic inerting system is effectively a closed-loop architecture, and the exemplary mechanically-operable valve 10 could be located in the closed-loop fluid circuit at any location upstream of an inlet of the fuel tank.

According to an aspect of the invention, a valve includes: a valve body having an inlet, an outlet, and a fluid passage extending between the inlet and the outlet; a valve member that is movable in the valve body between an open position, in which the valve member is configured to open the fluid passage for permitting fluid flow therethrough, and a closed position, in which the valve member is configured to close the fluid passage for restricting fluid flow therethrough; a locking mechanism that is movable relative to the valve body and the valve member, the locking mechanism being configured to hold the valve member in a position relative to the valve body when the locking

mechanism is in a locked state; and a shape memory actuator operatively coupled to the locking mechanism and to the valve member; wherein the shape memory actuator is configured to actuate when a temperature of the shape memory actuator reaches or exceeds a predefined temperature, such that actuation of the shape memory actuator causes the locking mechanism to release the valve member thereby enabling the valve member to move relative to the valve body.

Embodiments of the invention may include one or more of the following additional features, alone or in any combination.

In some embodiments, when the locking mechanism is in the locked state, the valve member is held in the open position; and wherein when actuation of the shape memory actuator causes the locking mechanism to release the valve member, the valve member is moved to the closed position.

In some embodiments, the valve member is configured as a poppet.

In some embodiments, the valve further includes a biasing spring that biases the valve member toward the closed position.

In some embodiments, the valve member has a hollow body portion that defines an internal chamber, and the valve member has at least one orifice extending through the body portion of the valve member to communicate fluid into the internal chamber.

In some embodiments, the locking mechanism includes a locking sleeve that is axially movable relative to the valve body, and the locking mechanism includes a locking element that is radially movable relative to the valve body.

In some embodiments, when the locking mechanism is in the locked state, the locking element engages the valve body and the valve member to interfere with the relative axial movement of the valve body and the valve member, thereby holding the valve member in the position.

In some embodiments, when the locking mechanism is in a release state caused by actuation of the shape memory actuator, the locking element disengages from the valve body and/or the valve member to permit relative axial movement of the valve body and the valve member, thereby enabling the valve member to move from the position.

In some embodiments, the locking mechanism includes a locking sleeve and a locking element that cooperates with the locking sleeve.

In some embodiments, when the locking mechanism is in the locked state, the locking sleeve is in a locked position, the locking sleeve in its locked position being operative to hold at least one locking element at a locked position such that the locking element protrudes radially outwardly through an aperture in a body portion of the valve member and into a locking groove in the valve body, thereby holding the valve member relative to the valve body.

In some embodiments, when the locking mechanism is in a release state caused by actuation of the shape memory actuator, the locking sleeve is axially moved to a release position, the locking sleeve in its release position enabling radially inward movement of the locking element for disengagement from the locking groove in the valve body, thereby releasing the valve member by enabling movement of the valve member relative to the valve body.

In some embodiments, the locking sleeve has a groove that enables the radially inward movement of the locking element when the locking sleeve is in the release position.

In some embodiments, the locking sleeve is slidably movable within an internal chamber of the valve member.

In some embodiments, the valve further includes a biasing member that biases the locking sleeve toward its locked position.

In some embodiments, the shape memory actuator comprises a shape memory material, the shape memory material having a heat sensing portion in thermal communication with fluid flowing through the fluid passage when the valve is in use.

In some embodiments, heating of the shape memory material via the heat sensing portion to a temperature that reaches or exceeds the predefined temperature causes the shape memory actuator to actuate.

In some embodiments, the shape memory actuator has a shape memory force when the shape memory actuator is actuated, the shape memory force being greater than a biasing force of a biasing member of the locking

mechanism, such that actuation of the shape memory actuator causes the locking mechanism to transition from the locked state to a release state.

In some embodiments, the shape memory actuator includes a shape memory material, and a majority of the shape memory material is disposed in the fluid passage of the valve.

In some embodiments, the shape memory actuator includes an actuator wire that includes a shape memory material.

In some embodiments, when the locking mechanism is in the locked state, the actuator wire is maintained in tension between the locking mechanism and the valve member.

In some embodiments, when the actuator wire is heated to the predefined temperature, the shape memory material changes shape and causes the actuator wire to shorten, thereby drawing respective axial ends of the locking mechanism and the valve member closer together.

In some embodiments, the valve body extends in an axial direction and has a valve seat; wherein the valve member is configured as a poppet slidably disposed in the valve body for opening and closing the valve by engaging the valve seat; wherein the locking mechanism includes a locking element and a locking sleeve; wherein the shape memory actuator includes an actuator wire comprising a shape memory material; the valve further including a poppet spring that biases the poppet to the closed position; wherein: the locking element is configured to hold the poppet in the open position under normal operating conditions; the locking sleeve is slidably disposed within the poppet, the locking sleeve being configured to release the locking element to activate the valve; the actuator wire is configured to shorten when a temperature of the shape memory material reaches or exceeds the predefined temperature, the actuator wire extending axially through the poppet and locking sleeve and being supported at a first end by the poppet and at a second end by the locking sleeve; the actuator wire is maintained in tension by a locking sleeve spring, and when the actuator wire shortens as a result of the temperature of the shape memory material reaching or exceeding the predefined temperature, the locking sleeve retracts relative to the poppet against the force of the locking sleeve spring, thereby releasing the locking element and allowing the poppet spring to urge the poppet to the closed position.

According to another aspect of the invention, a valve includes: a locking mechanism; a spring-biased poppet that is configured to be held in position by the locking mechanism in a normal operating state; and a shape memory actuator operatively coupled to the locking mechanism; wherein the shape memory actuator is configured to deactivate the locking mechanism thereby releasing the poppet when a temperature of the shape memory actuator reaches or exceeds a preset temperature.

In some embodiments, the locking mechanism includes a locking sleeve slidably movable within the poppet, and at least one locking element that is radially movable between lock and release positions to hold or release the poppet.

According to another aspect of the invention, a fuel tank inerting system includes: a fluid circuit having an outlet for connecting to a fuel tank; an inert-gas generator, such as an air separation module, in the fluid circuit upstream of the outlet; and a mechanically-operable over-temperature shutoff valve in the fluid circuit upstream of the outlet, wherein the mechanically-operable over temperature shutoff valve is the valve according to one or more of the foregoing aspects or embodiments.

According to another aspect of the invention, a fuel tank inerting system includes: a fluid circuit connected to a fuel tank; an inert-gas generator in the fluid circuit upstream of the fuel tank; and a mechanically-operable over temperature shutoff valve in the fluid circuit upstream of the fuel tank; wherein the over-temperature shutoff valve has a shape memory actuator that is configured to sense a temperature of fluid in the fluid circuit, and wherein when the fluid temperature causes the shape memory actuator to reach or exceed a predefined temperature, the shape memory actuator is configured to activate the shutoff valve to close, thereby restricting fluid flow to the fuel tank.

In some embodiments, the mechanically-operable over-temperature shutoff valve is the valve according to one or more of the foregoing aspects or embodiments. According to another aspect of the invention, a method of operating a valve, includes: holding a valve member in an open position with a locking mechanism; heating a shape memory material of a shape memory actuator with fluid flowing through the actuator, wherein the shape memory actuator is operatively connected to the valve member and the locking mechanism; when a temperature of the shape memory material reaches or exceeds a predefined temperature, actuating the shape memory actuator thereby causing the locking mechanism to release the valve member; and after actuating the shape memory actuator, moving the valve member to a closed position.

It is to be understood that terms such as“top,”“bottom,”“upper,”“lower,” “left,”“right,”“front,”“rear,”“forward,” “rearward,” and the like as used herein may refer to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference. Furthermore, the terms“upstream,”“downstream,”“inlet,” or “outlet” refer to the arrangement of components along a fluid flow path, as viewed in Fig. 4, for example, which is done realizing that fluid may flow in either direction through the valve.

An“operable connection,” or a connection by which entities are“operably connected,” as used herein is one in which the entities are connected in such a way that the entities may perform as intended. An operable connection may be a direct connection or an indirect connection in which an intermediate entity or entities cooperate or otherwise are part of the connection or are in between the operably connected entities.

A“controller” as used herein may include all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The controller may include, in addition to hardware, code that creates an execution environment for the computer program in question

Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e. , that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.