Patent Publication Number: US-9415250-B2

Title: Dry sprinkler

Description:
RELATED APPLICATION 
     This application is a continuation-in-part application of application Ser. No. 13/722,571 filed on Dec. 20, 2012 and entitled “Dry Sprinkler.” 
    
    
     TECHNICAL FIELD 
     This disclosure relates to dry sprinklers that are used in fire protection systems in buildings and other structures, and more particularly to dry sprinklers having a flexible conduit that extends between a sprinkler head and a sprinkler valve. The dry sprinkler can be connected to a branch fluid supply line that distributes fire suppression fluid, such as water. 
     BACKGROUND 
     Dry sprinklers are used in fire protection systems to extinguish or suppress fires. Dry sprinklers can be connected to a fluid distribution system that is installed in buildings or other structures. The fluid distribution system is connected to a fluid supply, specifically water or another fire suppression fluid. Dry sprinklers usually include a sprinkler head and a rigid, inflexible conduit connecting the sprinkler head to a connector fitting on a branch fluid supply line. The conduit includes a valve that is positioned at the connector fitting end, and the valve remains closed under normal conditions so that no fluid enters the sprinkler conduit until the sprinkler is actuated to release the fire suppression fluid. Dry sprinklers have sprinkler heads that are equipped with a thermally responsive component that is designed to be activated in the event of fire. 
     The thermally responsive component of the fire sprinkler head rapidly triggers the valve to open and release fluid through the sprinkler to extinguish the fire. As the triggering mechanism, dry sprinklers usually employ a rigid, inflexible link member that is positioned between the valve and the fire sprinkler head and is pressed against the fire sprinkler head by the force of fluid that is incident on the valve. When the thermally responsive element reacts in response to a fire, the link member is pushed out of the way of the valve by the fluid pressure or gravity, which causes the valve to open. 
     SUMMARY 
     Dry sprinklers can be particularly useful in unconditioned (e.g., unheated) spaces such as attics, balconies, breezeways, and walkways, because the conduit of a dry sprinkler contains no fluid under normal conditions and there is therefore less risk of freeze breakages or other damage. Accordingly, in contrast to wet sprinkler systems, there is no need to take countermeasures to prevent freezing of the fluid in the sprinkler. For similar reasons, dry sprinklers are useful in spaces that are maintained under refrigerated (including freezing) conditions. 
     Installation of dry sprinklers can be difficult. During installation of the sprinkler system, the fluid distribution system is usually first installed, including the network of pipes with the branch fluid supply lines. Once the branch lines are installed, the installer determines the lengths of the dry sprinkler that is needed based on the distance from the desired sprinkler head location to the connector fitting on the branch line. The dry sprinklers are ordered at the specific length and configuration determined by the installer, and the dry sprinklers are then made-to-order and shipped to the installer, which can cause delays in construction of up to two weeks or more. Such delays are undesirable and can greatly increase construction expense. Alternatively, the system designer and/or specifications may mandate the sprinkler lengths. However, even in those circumstances, adjustments may have to be made in the field, which may cause undesired delays. 
     Also, once the branch line piping has been installed, it is difficult to move the location of the sprinkler head. Likewise, in some cases, the location of the sprinkler head will be limited by the construction based on where the branch line pipe can be installed. 
     According to one aspect, a dry sprinkler is provided that includes a fluid conduit that is configured to couple to a fluid supply, a valve that is positioned proximate to a first end of the conduit, the valve having a closed state that prevents fluid from the fluid supply from flowing through the conduit and an open state that allows fluid from the fluid supply to flow through the conduit, a fire sprinkler head positioned proximate to a second end of the conduit, the fire sprinkler head having a thermally responsive element that reacts to an elevated temperature condition, and an unbiased tie positioned within the conduit that is operably coupled to the valve, where the unbiased tie has at least an unengaged state and an engaged state. The unbiased tie is not biased towards the sprinkler head in the unengaged state, the reaction of the thermally responsive element to the elevated temperature condition causes the tie to change from the unengaged state to the engaged state, and changing the tie to the engaged state from the unengaged state allows the valve to change from the closed state to the open state. 
     According to another aspect, a dry sprinkler is provided that includes a flexible conduit that is configured to be coupled to a fluid supply, a valve positioned proximate to a first end of the conduit, the valve having a sealing member that is urged to a closed position in which fluid from the fluid supply is prevented from flowing through the conduit, the sealing member being movable to an open position in which fluid from the fluid supply flows through the conduit, a fire sprinkler head positioned proximate to a second end of the conduit, the fire sprinkler head having a thermally responsive element that is configured to react to an elevated temperature condition, an unbiased tie positioned within the flexible conduit and being present in the flexible conduit in a state such that the unbiased tie is not biased toward the fire sprinkler head, a first portion of the unbiased tie being operably coupled to the sealing member to urge it to the open position when the unbiased tie is engaged, an engagement action connected to the second portion of the unbiased tie, the engagement action being operably coupled to the thermally responsive element so that when the thermally responsive element reacts to the elevated temperature condition, the engagement action is triggered to apply tension to the unbiased tie thereby causing the tie to move the sealing member to the open position. 
     According to another aspect, a dry sprinkler is provided that includes a flexible conduit that is configured to be coupled to a fluid supply line, a valve positioned proximate to a first end of the conduit, the valve having a closed state in which fluid from the fluid supply is prevented from flowing through the conduit and an open state in which fluid from the fluid supply is allowed to flow through the conduit, an unbiased tie having a first portion that is operably coupled to the valve to open the valve when the unbiased tie is engaged, the unbiased tie being present in a state such that the tie is not biased toward the second end of the conduit, a sheath member that is located within the conduit and surrounds the unbiased tie over most of the length of the unbiased tie, and a fire sprinkler head positioned proximate to a second end of the conduit, the fire sprinkler head having a thermally responsive element that reacts to an elevated temperature condition. The unbiased tie is operably connected to the thermally responsive element so that the reaction of the thermally responsive element to the elevated temperature condition causes the tie to be engaged. 
     According to another aspect, a dry sprinkler is provided that includes a flexible conduit, a valve located proximate to a first end of the flexible conduit, a fire sprinkler head located proximate to a second end of the flexible conduit, an unbiased tie located within the flexible conduit and being present in a state such that the unbiased tie is not biased toward the fire sprinkler head, a first portion of the unbiased tie being operably coupled to the valve such that tensioning the tie allows the valve to move to an open position, and tensioning means for applying tension to the unbiased tie. 
     According to another aspect, a fire protection sprinkler system is provided that includes a network of pipes connected to a fluid supply, a control valve in fluid communication with the network of pipes and the fluid supply, the control valve configured to control the flow of fluid between the fluid supply and the network of pipes, at least one dry sprinkler fluidly connected to the network of pipes, the dry sprinkler including a conduit, a fire sprinkler head positioned proximate to the fluid outlet of the conduit, the fire sprinkler head having a thermally responsive element that reacts to an elevated temperature condition, a sprinkler valve positioned proximate the fluid inlet and having a closed state preventing flow of fluid through the conduit, and an open state allowing flow of fluid through the conduit, an unbiased tie positioned within the conduit and being present in the conduit in a state such that the unbiased tie is not biased toward the fire sprinkler head, a first portion of the unbiased tie being operably coupled to the sprinkler valve such that engaging the unbiased tie allows the valve to move to the open state, and an engagement action that is coupled to a second portion of the unbiased tie, and reaction of the thermally responsive element to the elevated temperature condition causes the engagement action to apply tension to the unbiased tie. 
     According to another aspect, a dry sprinkler is provided that includes a flexible conduit that is configured to be coupled to a fluid supply line, a valve positioned proximate to a first end of the conduit, the valve having a closed state in which fluid from the fluid supply is prevented from flowing through the conduit and an open state in which fluid from the fluid supply is allowed to flow through the conduit, an unbiased tie having a first portion that is operably coupled to the valve such that engaging the unbiased tie allows the valve to open, the unbiased tie being present in a state such that the tie is not biased toward the second end of the conduit, and a fire sprinkler head positioned proximate to a second end of the conduit, the fire sprinkler head having a thermally responsive element that reacts to an elevated temperature condition. The unbiased tie is operably connected to the thermally responsive element so that the reaction of the thermally responsive element to the elevated temperature condition causes the tie to be engaged. 
     According to another aspect, a dry sprinkler is provided that includes a flexible conduit that is configured to be coupled to a fluid supply, a valve positioned proximate to a first end of the conduit, the valve having a closed state in which fluid is prevented from flowing through the conduit and an open state in which fluid is allowed to flow through the conduit, an uncompressed tie having a first portion that is operably coupled to the valve such that engaging the uncompressed tie allows the valve to open, the uncompressed tie being present in a state such that it is not under compressive force, and a fire sprinkler head positioned proximate to a second end of the conduit, the fire sprinkler head having a thermally responsive element that reacts to an elevated temperature condition, wherein the uncompressed tie is operably connected to the thermally responsive element. 
     According to another aspect, a dry sprinkler is provided that includes a flexible conduit that is configured to be coupled to a fluid supply, a valve positioned proximate to a first end of the conduit, the valve having a closed state in which fluid is prevented from flowing through the conduit and an open state in which fluid is allowed to flow through the conduit, a substantially non-rigid tie having a first portion that is operably coupled to the valve such that engaging the non-rigid tie allows the valve to open, and a fire sprinkler head positioned proximate to a second end of the conduit, the fire sprinkler head having a thermally responsive element that reacts to an elevated temperature condition, wherein the non-rigid tie is operably connected to the thermally responsive element. 
     According to yet another aspect, a method of triggering a dry sprinkler in the event of a fire is provided, where the dry sprinkler includes (i) a conduit that is coupled to the fluid supply, (ii) a valve that is positioned proximate to a first end of the conduit and is urged to a closed state to prevent fluid from the fluid supply from flowing through the conduit, (iii) a fire sprinkler head that is positioned proximate to a second end of the conduit and includes a thermally responsive element that reacts to an elevated temperature condition, and (iv) a nontensioned tie that is operably coupled to the valve such that engaging the nontensioned tie allows the valve to open, and the method includes the steps of engaging the tie upon reaction of the thermally responsive element to the elevated temperature condition and applying tension to the tie at least until the valve opens and allows fluid from the fluid supply to flow through the conduit. 
     According to still another aspect, a method of installing a flexible dry sprinkler on a branch fluid line is provided. The method includes (i) providing a flexible dry sprinkler, which includes a flexible conduit, a valve disposed proximate to the inlet end of the flexible conduit, the valve having a closed state that prevents flow of fluid from the fluid supply through the conduit and an open state that allows flow of fluid from the fluid supply through the conduit, a fire sprinkler head positioned proximate to the outlet end of the conduit, the fire sprinkler head having a thermally responsive element that reacts to an elevated temperature condition, and a tie positioned within the flexible conduit, the tie having a first portion and a second portion, the first portion being operably connected to the valve to urge the valve to an open position when the tie is engaged, and the second portion being operably connected to the thermally responsive element to engage the tie when the thermally responsive element reacts to an elevated temperature condition, (ii) connecting the flexible dry sprinkler to the branch fluid line, (iii) bending the flexible conduit to locate the fire sprinkler head, and (iv) securing the flexible dry sprinkler in a fixed position with a bracket. The flexible dry sprinkler is installed on the branch line and secured with the bracket without engaging the tie and without opening the valve. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments are described in detail below with reference to the accompanying drawings in which: 
         FIG. 1  is a schematic diagram illustrating a fire protection sprinkler system; 
         FIGS. 2A-2C  are cross-sectional schematic diagrams of a flexible dry sprinkler according to one embodiment; 
         FIG. 3  is a cross-sectional schematic diagram of a rigid, inflexible dry sprinkler according to one embodiment; 
         FIG. 4  is a perspective view of a flexible dry sprinkler according to one embodiment; 
         FIG. 5  is an enlarged view of the second end section (fluid outlet) of the flexible dry sprinkler shown in  FIG. 4 ; 
         FIGS. 6A-6B  are cross-sectional views of the second end section shown in  FIG. 5  illustrating the dry sprinkler in a normal state ( FIG. 6A ) and illustrating the dry sprinkler in a state after the thermally responsive element reacts to an elevated temperature condition ( FIG. 6B ); 
         FIGS. 7A-7B  are cross-sectional views showing another embodiment of a flexible dry sprinkler in a normal state ( FIG. 7A ) and showing the flexible dry sprinkler in a state after the thermally responsive element reacts to an elevated temperature condition ( FIG. 7B ); 
         FIGS. 8A-8B  are cross-sectional views showing the second end of another embodiment of a flexible dry sprinkler in a normal state ( FIG. 8A ) and showing the second end of the flexible dry sprinkler in a state after the thermally responsive element reacts to an elevated temperature condition ( FIG. 8B ); 
         FIGS. 9A-9B  are cross-sectional views showing the second end of another embodiment of a flexible dry sprinkler in a normal state ( FIG. 9A ) and showing the second end of the flexible dry sprinkler in a state after the thermally responsive element reacts to an elevated temperature condition ( FIG. 9B ); 
         FIGS. 10A-10B  are cross-sectional views showing the second end of another embodiment of a flexible dry sprinkler in a normal state ( FIG. 10A ) and showing the flexible dry sprinkler in a state after the fire sprinkler head reacts to an elevated temperature condition ( FIG. 10B ); 
         FIG. 11A  is an exploded cross-sectional view showing the components of the first end section (valve and valve catch portion) of another embodiment of a dry sprinkler,  FIG. 11B  is a partial cross-sectional view illustrating the first end section of the dry sprinkler in a normal state, and  FIG. 11C  is a partial cross-sectional view illustrating the first end section of the dry sprinkler once the tie is engaged in response to an elevated temperature condition; 
         FIGS. 12A-12B  are partial cross-sectional views illustrating the first end section of another embodiment of a dry sprinkler in a normal state ( FIG. 12A ) and showing the first end section once the tie is engaged in response to an elevated temperature condition ( FIG. 12B ); 
         FIGS. 13A-13B  are partial cross-sectional views illustrating the first end section of another embodiment of a dry sprinkler in a normal state ( FIG. 13A ) and showing the first end section once the tie is engaged in response to an elevated temperature condition ( FIG. 13B ); 
         FIGS. 14A-14B  are cross-sectional views illustrating the first end section of another embodiment of a dry sprinkler in a normal state ( FIG. 14A ) and showing the first end section once the tie is engaged in response to an elevated temperature condition ( FIG. 14B ); 
         FIGS. 15A-15B  are partial cross-sectional views illustrating the first end section of another embodiment of a dry sprinkler in a normal state ( FIG. 15A ) and showing the first end section once the tie is engaged in response to an elevated temperature condition ( FIG. 15B ); 
         FIGS. 16A-16C  are cross-sectional views illustrating a flexible dry sprinkler with a tie sheath; 
         FIGS. 17A-17B  are cross-sectional views illustrating the second end of another embodiment of a dry sprinkler of this invention in a normal state ( FIG. 17A ) and illustrating the second end of the dry sprinkler in a state after the thermally responsive element reacts to an elevated temperature condition ( FIG. 17B ); 
         FIG. 18A  is a cross-sectional elevation view illustrating the first end section of another embodiment of a dry sprinkler of this invention in a normal state; and 
         FIGS. 18B and 18C  are cross-sectional, perspective views of the first end section illustrated in  FIG. 18A , illustrating the first end section in a normal state ( FIG. 18A ) and illustrating the first end section once the tie is engaged in response to an elevated temperature condition ( FIG. 18B ). 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The dry sprinklers provided by this disclosure can be used in connection with fire protection sprinkler systems that are installed in buildings or on other structures.  FIG. 1  is a schematic representation of an exemplary embodiment of a fire protection sprinkler system  10  that is installed in structure  12 . The fire protection sprinkler system  10  includes a fluid supply line  14  that is connected to a supply of fire suppressive fluid. The fluid supply can be a water source such as the water supply that is provided by municipalities, a water container, or a container containing a fire suppressive fluid other than water (e.g., fluid for a fire suppressive foam, powder or similar fire suppressant). 
     The fluid supply line  14  connects to a control valve  16  that controls fluid supply to a network of pipes  18 . The control valve  16  is in fluid communication with a main fluid supply line  17  that supplies fire suppression fluid to a plurality of branch lines  19  that extend from the main line  17 . Each of the branch lines  19  supplies the fire suppression fluid to a plurality of dry sprinklers  15 . In the event of a fire (or other similar elevated temperature event), the dry sprinklers  15  are configured to distribute the fire suppression fluid within the structure  12  to extinguish or suppress the fire. 
     Although  FIG. 1  illustrates the dry sprinklers  15  in a pendant position, the sprinklers can be configured in any position, including an upright, pendant or sidewall position. 
       FIGS. 2A-2C  are schematic diagrams illustrating a flexible dry sprinkler  250 . The dry sprinkler  250  is connected to branch line  272 . The dry sprinkler  250  includes a conduit  210  with a first end portion  225  and a second end portion  235 . A connector  275  fluidly connects the first end portion  225  to the branch line  272 . For example, the connector  275  can include a threaded opening to receive corresponding threads on first end portion  225  of the dry sprinkler  250 . 
     The connection of the dry sprinkler  250  to the branch line  272  forms a connection axis Y in the center of the branch line connector  275  along the length of the conduit  210  in its unbent shape (see e.g.,  FIG. 2A ). The conduit  210  has a length labeled as D LEN . 
     The dry sprinkler  250  can include a valve (not illustrated in  FIGS. 2A-2C ) positioned proximate to the first end  225  of the conduit  210 . As discussed in greater detail below, the valve has an open state that allows fluid to flow from the branch line  272  through the conduit  210  and a closed state that prevents fluid from flowing from the branch line  272  through the conduit  210 . This valve is sometimes referred to herein as a “sprinkler valve” to distinguish it from a main control valve, for example. 
     A fire sprinkler head  240  is coupled to the second end portion  235  of the dry sprinkler  250 . The fire sprinkler head is configured to react to the elevated temperature condition in the event of fire to trigger the valve to open. The fire sprinkler head  240  can be coupled to the conduit in any suitable way, for example, by connecting a threaded end of the sprinkler head to a threaded end of the conduit or by mechanically coupling the sprinkler head into the second end of the conduit. 
     The dry sprinkler  250  includes a tie  220  that is positioned within the conduit  210  in this embodiment. The tie  220  generally extends from the first end portion  225  of the conduit to the second end portion  235  of the conduit and operably connects to the valve to open the valve after the fire sprinkler head reacts to the elevated temperature condition. 
     The tie  220  has an unengaged state and an engaged state.  FIGS. 2A-2C  illustrate the tie  220  in an unengaged state, which is the state that the tie  220  is in when the valve is closed. As discussed in detail below, in the event of fire, thermally responsive element  242  of the fire sprinkler head  240  reacts and triggers an engagement apparatus (also referred to herein as an “engagement action”) that engages the tie  220  by applying a load to the tie  220 . The load is applied by the tie  220  to a valve catch. The valve catch allows the valve to move to an open state. The tie  220  thus has an “unengaged state” in which the tie is operably coupled to the valve but the valve remains closed, and an “engaged state” in which the tie is operative to open the valve, e.g., when a load is applied to the tie. Once the tie is engaged, the valve opens and can be maintained in an open state while the tie continues to be engaged, or the valve can be thereafter maintained in an open state even if the tie returns to an unengaged state. 
     The tie  220  can be characterized by one or more of the following:
         (a) In an unengaged state, the tie is unbiased such that it is not biased toward the sprinkler head (excepting, of course, by its own weight from the force of gravity) and/or the valve. The term “unbiased” describes a configuration in which no force is applied to the tie to urge it in the direction of the sprinkler head and/or valve. Thus, for example, fluid pressure that impinges on the valve does not apply a force to the tie to urge it towards the sprinkler head or valve, and there is likewise no mechanical device that urges the tie toward the sprinkler head or valve;   (b) In an unengaged state, the tie is not under any compressive force (likewise excepting gravitational forces), e.g., the tie is not pressed against a portion of the dry sprinkler by the fluid pressure that is incident upon the valve;   (c) In an unengaged state, the tie is not under tension, and in an engaged state the tie is under tension;   (d) In an unengaged state, the tie has substantially no rigidity;   (e) The tie cannot support its own weight and cannot support a bending stress;   (f) The tie can be bent entirely around a radius that is smaller than a cross-sectional dimension of the tie;   (g) The tie is flexible;   (h) The tie is relatively inelastic such that it does not stretch significantly in the engaged state (e.g., the tie can have an elastic modulus of from 100 MPa to 150 GPa, from 1 GPa to 50 GPa, and from 2 GPa to 10 GPa).       

     By way of example, the tie  220  can include a cord, a rope, a string, a loop, a chain, a chain-like member where chain link portions connect once the tie is engaged, a cable, a ribbon, a tube, a wire, a monofilament line, and a multifilament line. In the illustrated embodiments, the tie  220  is positioned entirely within the conduit. However, in some configurations, only a portion of the tie  220  can be positioned within the conduit or the entire tie  220  can be positioned outside of the conduit or in a sidewall of the conduit. 
     A first portion of the tie  220  can be connected to the valve catch and a second portion of the tie  220  can be connected to the engagement action. The tie  220  thus can extend from the valve catch to the engagement action, and typically extends along at least 40 percent of the length of the conduit  210 , at least 60 percent of the length of the conduit  210 , or at least 90 percent of the length of the conduit  210 . The tie is typically positioned to cross the midpoint of the conduit  210 . The size and cross-sectional dimension of the tie  220  are not particularly important so long as the tie is operable to open the valve within a desired response time. 
     As shown in  FIGS. 2B and 2C , the conduit  210  of the dry sprinkler  250  can be flexible. Providing a flexible conduit can have significant advantages. For example, whereas in a rigid, inflexible dry sprinkler, the location of the fire sprinkler head is fixed based on the length and shape of the dry sprinkler and the location and position of the connector  275 , in a flexible dry sprinkler, the location of the fire sprinkler head can be moved or variously oriented relative to the connector  275 , only limited by the length and flexibility of the conduit. Using a flexible dry sprinkler is also advantageous because the specific location of the fire sprinkler head can be varied even after the network of pipes is installed. In this regard, for rigid, inflexible dry sprinklers, the network of pipes is installed in a structure, the desired locations of the sprinkler heads are determined, and the dry sprinklers are selected so that the fire sprinkler heads are positioned at or near the desired locations. This can cause some construction delays based on the time it takes for the dry sprinklers to be ordered, fabricated and delivered. Also, the dry sprinklers are typically made-to-order. In contrast, by using flexible dry sprinklers, an installer or building contractor can keep sprinklers of discrete lengths on hand and can adjust the position and angle of the sprinkler head as need requires. This should reduce construction delays. Also, the dry sprinkler manufacturer can prefabricate and supply sprinklers of discrete dimensions based on anticipated need. 
     The flexible conduit  210  can be used with a tie  220  having one or more of the characteristics described above, and the tie  220  can be configured with the conduit  210  so that the tie  220  is not inadvertently engaged during installation. In this regard, the tie  220  can be configured so that the fire sprinkler head can be positioned and secured at the desired location without inadvertently engaging the tie  220  and opening the valve. 
     As shown in  FIGS. 2B and 2C , the second end of the flexible conduit  210  can be laterally displaced with respect to the first end of the conduit  210  by a distance D LAT . The distance of lateral displacement can be characterized as a portion or percentage of the length of the conduit (D LEN ). The flexible conduit  210  can therefore be characterized in that the second end of the conduit  210  can be laterally displaced with respect to the first end of the conduit at a distance corresponding to at least 5 percent of the length of the conduit  210 , at least 10 percent of the length of the conduit  210 , at least 30 percent of the length of the conduit  210 , from 30 to 95 percent of the length of the conduit  210 , or from 50 to 90 percent of the length of the conduit  210 . 
     As also shown in  FIGS. 2B and 2C , the flexibility of the conduit can further be characterized by comparing D LEN  with the vertical distance between the two ends of the conduit (D VERT ) when the sprinkler is in a bent state. The flexible conduit can be characterized in that the conduit is capable of bending such that D VERT  corresponds to 75 percent or more of D LEN , 50 percent or more of D LEN , or 10 percent or more of D LEN . 
     As shown in  FIG. 2C , the angle α is the angle that the conduit  210  can be bent to achieve a desired location and orientation of the sprinkler head. In this regard, the fire sprinkler head can be positioned and secured so that the fire suppression fluid exits the dry sprinkler  250  at any desired angle. For example, whereas a straight inflexible sprinkler is fixed with respect to the connection axis Y at an angle of 180°, the flexible dry sprinkler can be configured such that the sprinkler head axis X can be displaced relative to the connection axis Y at an angle (α) of from 20° to 160°, from 45° to 135°, and from 75° to 105°. 
     The tie  220  is provided in or along the conduit  210  with enough slack such that (i) the tie  220  has a free length that is greater than the length of the conduit  210  that extends between the points where the tie is attached in the dry sprinkler; (ii) the fire sprinkler head can be laterally displaced with respect to the first end of the conduit by the maximum combination distance and angle (e.g., the D LAT  distances and angles α discussed above) without a load being applied to the tie  220  that would open the valve. The presence of that slack in the tie  220  minimizes the risk that the valve will be accidentally opened when the sprinkler is transported, installed or used. 
     The flexible conduit  210  can include a flexible portion that comprises, for example, a corrugated tube, a hose, or a braided tube, which can be made from known materials including metal, rubber, etc. The flexible conduit  210  can include one or more flexible portions along at least 20 percent of the conduit length (D LEN ), along at least 40 percent of the conduit length, along at least 60 percent of the conduit length, along at least 80 percent of the conduit length, from 50 to 95 percent of the conduit length, or along its entire length. The flexible conduit  210  can have a low elasticity so that when it is bent into a desired position it maintains its bent shape and does not return to its original position. 
     In some embodiments, the flexible conduit  210  includes an inflexible portion proximate to the first end  225  (fluid inlet end) that surrounds the valve and enables the conduit to be connected to branch line  272 . The flexible conduit  210  can also include an inflexible portion that is proximate to the second end  235  (fluid outlet end) of the conduit that enables the fire sprinkler head to be connected to the conduit. The inflexible portion proximate to the second end  235  can also include a reducer that is formed to have at least one flat surface so that the second end of the conduit can be secured into place by affixing a bracket to the flat surface. The other end of the bracket can be affixed to a secure structure. The bracket and inflexible portion of the conduit can be configured so that the sprinkler head is secure and resists torsional forces. In general, the installation of the sprinkler system including the bracing should comply with applicable codes and guidelines that are used in this field. 
     The dry sprinklers can have discrete lengths of, for example, 1 ft., 2 ft., 4 ft., 6 ft., or any length there between. 
     In some embodiments, the dry sprinkler can be rigid and inflexible.  FIG. 3  illustrates an embodiment of an inflexible dry sprinkler  350  that includes a rigid, inflexible conduit  310 . The inflexible dry sprinkler is otherwise the same as the embodiment described in connection with  FIG. 2 , and the similar parts are identified with corresponding numbers. For example, the rigid, inflexible dry sprinkler  350  also includes an unbiased tie  320  that is depicted in an unengaged state in  FIG. 3 . The tie  320  is operably coupled to the thermally responsive element  342  of the sprinkler head  340  so that the tie becomes engaged when the thermally responsive element  342  reacts to an elevated temperature condition. Once the tie  320  becomes engaged, the valve opens and a fire suppression fluid is allowed to flow out of the sprinkler. 
       FIGS. 4-6B  depict an embodiment of a flexible dry sprinkler and illustrate the operation of the fire sprinkler head and the engagement action that engages the tie to cause the valve to open. 
     Referring to  FIG. 4 , the flexible dry sprinkler  450  includes a flexible conduit  410  that includes a flexible portion made of a metallic corrugated tube  412 . The flexible conduit  410  has a first end portion  425  and a second end portion  435 . The first end portion  425  includes a connector  428  with a threaded portion  421  that is configured to connect the dry sprinkler  450  to a branch line of a pipe network. The second end portion  435  of the flexible conduit has a reducer  438  that houses an engagement action  455  for engaging the tie  420  ( FIGS. 6A-6B ). A fire sprinkler head  440  is coupled to the second end portion  435 . The reducer segments of the flexible conduit can be inflexible. 
     Referring to  FIGS. 5-6B , the fire sprinkler head  440  is fitted into the second end of the conduit  410  in reducer  438 . The fire sprinkler head  440  includes a body  447  that defines an opening  449  extending therethrough, a thermally responsive element  442 , pip cap  448  and spacer  441  that are positioned in the opening  449 , arms  444  that extend from the body  447 , and a deflector  446  that is provided at the apex of the arms  444  to divert the flow of fluid laterally and downwardly when the sprinkler is activated. The thermally responsive element  442  can be, e.g., a glass bulb that breaks at a predetermined temperature or a fusible element that has a melting portion that melts at a predetermined temperature. Either of these reactions to the elevated temperature causes the pip cap  448  and spacer  441  to lose support and fall toward the deflector  446 . The thermally responsive element can be set to react to different elevated temperature conditions, and can react when the temperature reaches, for example, 135° F., 175° F., 250° F., 325° F., 400° F. or even higher. 
     In this embodiment, the thermally responsive element  442 , pip cap  448  and spacer  441  are operably coupled to the engagement action  455 . A tubular support  472  is supported by spacer  441 , which is in turn supported by the pip cap  448 . The tubular support  472  includes pin  470  that fits in the detent  459  of shaft  454 . 
     Shaft  454  is rotatably mounted in the flexible conduit  410 . That shaft  454  is rotatably biased in one direction with a torsion spring  456  that is provided on the outside of reducer  438  within housing  452 . In normal conditions, the pin  470  engages the detent  459  and prevents the shaft  454  from rotating. The shaft  454  includes a tie connection  457  that connects the tie  420  to the shaft  454 . 
       FIG. 6A  is a cross-sectional view of dry sprinkler  450  when the tie  420  is in an unengaged state and  FIG. 6B  is a cross-sectional view of the dry sprinkler  450  when the tie  420  is in an engaged state. The tie  420  illustrated in  FIGS. 6A-B  is a flexible string or a string-like member, such as a rope, ribbon or wire. In its unengaged state ( FIG. 6A ), the tie  420  is provided with slack, and is not biased in a direction toward the fire sprinkler head or in a direction toward the valve. As discussed in detail below, the tie  420  is operably coupled to the valve by a valve catch that is positioned proximate to the first end portion  425  ( FIG. 4 ) of the flexible conduit  410 . The valve catch (embodiments of which are described below in connection with  FIGS. 11A-15B ) is configured to cause the valve to move to an open state when the tie  420  is tensioned. 
     As shown in  FIG. 6B , in the event of a fire or other elevated temperature condition, when the thermally responsive element  442  reacts to the elevated temperature condition, the spacer  441  and the support  472  will move outwardly with respect to the conduit  410 , i.e., toward the deflector  446 . The pin  470  will disengage from the detent  459 , allowing the rotatably biased shaft  454  to rapidly rotate, thereby winding the tie  420  around the shaft  454 . This action will apply a load to the tie  420 , tensioning the tie  420  and causing the tie  420  to pull on the valve catch. The valve catch will then open the valve and fluid will flow through the conduit and out of the sprinkler head. 
     The engagement action that engages the tie  420  to apply a load thereto is not particularly limited to the disclosed embodiments. In general, the engagement action can store energy in the form of mechanical energy, potential energy, hydraulic energy, chemical energy, etc., and can release the energy to engage the tie and apply a load when the engagement action is triggered by the reaction of the thermally responsive element of the sprinkler head. Moreover, where the engagement action operates to apply tension to the tie, it may do so by winding (as in the embodiment shown in  FIGS. 4-6 ), pulling, or otherwise displacing the tie to apply tension. Additional structures that may be operable to engage the tie are illustrated in  FIGS. 7-10 , and still other structures would be understood to be operable by those of ordinary skill in this field. 
       FIGS. 7A and 7B  illustrate an embodiment where the engagement action includes a weight that applies a load to tie  720 . Similar to the previously described embodiment, the dry sprinkler  750  includes a flexible conduit  710  with a corrugated tube  712 . The flexible conduit  710  includes a second end portion  735  that is coupled to a fire sprinkler head  740 . The tie  720  is a string or string-like member that is provided with slack in its normal or unengaged state ( FIG. 7A ). 
     The engagement action  755  can include a weight to which one end of the tie  720  is connected. The weight is supported by plug  748  of the fire sprinkler head  740 . As shown in  FIG. 7B , when the thermally responsive element  742  of the fire sprinkler head  740  reacts to the elevated temperature condition by breaking, the spacer  748  and the engagement action  755  fall through the sprinkler head  740 . The weight of the engagement action  755  removes the slack of the tie  720  thereby applying tension to the tie and causing the valve that is positioned at the first end portion  725  to open. Opening the valve causes fluid  780  to flow downward from the valve, through the conduit and out of the fire sprinkler head. 
     The engagement action of a flexible dry sprinkler according to yet another embodiment is illustrated by  FIGS. 8A and 8B . The engagement action  855  is provided within the flexible conduit  810  and is located proximate to the second end portion  835  of the conduit. The engagement action  855  includes a compression spring  856 , detents  857 , a pin  854 , and bushing  858 . The pin  854  is a tie coupling member and is connected to an end portion of tie  820 .  FIG. 8A  illustrates the tie in an unengaged state and  FIG. 8B  illustrates the tie in an engaged state. 
     The flexible dry sprinkler can include a fire sprinkler head  840  at its second end, which includes a body  847  defining an opening  849  therethrough. The fire sprinkler head  840  further includes a thermally responsive bulb  842 , and a pip cap  848  and a spacer  841  that are positioned in opening  849 . 
     As can be seen, the spacer  841  supports the bushing  858 , which in turn supports the pin  854  that is connected to the tie  820 . The compression spring  856  is present in the conduit under compression between detents  857  and the bushing  858 , thereby biasing the bushing  858  and pin  854  toward the sprinkler head  840 . The tie  820  in this embodiment is a string or string-like member that is provided with slack in its unengaged state, and is not affected by the compression of the spring in this state. The tie  820  remains unbiased toward the fire sprinkler head until the thermally responsive element  842  reacts to an elevated temperature condition. 
     As can be seen in  FIG. 8B , when the thermally responsive element  842  of the fire sprinkler head  840  reacts to an elevated temperature condition, the bulb breaks, which causes the pip cap  848  and spacer  841  to lose support. The compression spring  856  pushes the bushing  858  and pin  854  downward, which rapidly removes slack from the tie, and applies a load to the tie to open the valve. 
       FIGS. 9A-9B  illustrate another embodiment of an engagement action  955 . In this embodiment, the engagement action  955  is provided within the flexible conduit  910  and is located proximate to the second end portion  935  of the conduit. Although flexible conduit  910  includes flexible portions so that the location of the sprinkler head can be positioned as discussed above, the portion of flexible conduit  910  illustrated in  FIGS. 9A-9B  is rigid and inflexible, which facilitates normal operation of the engagement action  955  when the conduit is bent. The engagement action  955  includes a compression spring  956 , cross support member  958 , extension rod  954 , pivot bar  914 , and bushing  972 . The tie  920  is connected to cross support member  958 .  FIG. 9A  illustrates the tie in an unengaged state and  FIG. 9B  illustrates the tie in an engaged state. 
     Similar to the  FIG. 8  embodiment, a fire sprinkler head  940  is provided at the second end, which includes a thermally responsive bulb  942 , and a pip cap  948  and a spacer  941  that are positioned in opening  949 . The spacer  941  supports the bushing  972 , which in turn supports the pivot bar  914 , which supports extension rod  954  and cross support member  958 . The compression spring  956  is present in the conduit under compression between detent  957  and the cross support member  958 . The compression spring  956  urges the cross support member  958  downwardly toward the fire sprinkler head  940 . 
     The tie  920  in this embodiment is a string or string-like member that is provided with slack in its unengaged state, and is not affected by the compression of the spring in this state. As shown in  FIG. 9A , the tie  920  remains unbiased toward the fire sprinkler head until the thermally responsive element  942  reacts to an elevated temperature condition. 
     Referring to  FIG. 9B , when the thermally responsive element  942  of the fire sprinkler head  940  reacts to an elevated temperature condition, the bulb breaks, which causes the pip cap  948  and spacer  941  to lose support. The compression spring  956  pushes the cross support member  958  and extension rod  954  toward the fire sprinkler head, which causes the bushing  972  to move downwardly in  FIG. 9B . Once the bushing  972  moves down, the pivot bar  914  rotates from a horizontal position that supports extension rod  954  ( FIG. 9A ) to a vertical position that does not support extension rod  954  ( FIG. 9B ). Once the pivot bar  914  rotates, the extension rod  954  is pushed into the interior of bushing  972  as shown in  FIG. 9B . This causes the cross support member  958  to move rapidly toward the sprinkler head, which removes slack from the tie  920  and applies a load to the tie  920  to open the valve. As compared to the  FIG. 8  embodiment, this embodiment can allow a greater amount of slack to be removed from the tie because the portion of the engagement action that is coupled to the tie can travel a farther distance in the  FIG. 9  embodiment. 
     The engagement action of a flexible dry sprinkler according to still another embodiment is illustrated in connection with  FIGS. 10A and 10B . 
       FIG. 10A  illustrates a cut-away view of the second end  1035  of the flexible dry sprinkler in a normal state when the fire sprinkler head  1040  has not reacted to an elevated temperature condition. In this embodiment, the engagement action  1055  includes a cross support member  1058  that is supported by a pin  1054  that is in turn supported by the pip cap  1048  of the fire sprinkler head  1040 . The cross support member  1058  is rotationally biased and under compression between detents  1057  and compression spring  1056 . The tie  1020  is connected to the cross support member and is an untensioned string or string-like member. 
     As shown in  FIG. 10B , when the thermally responsive bulb  1042  of the fire sprinkler head  1040  reacts to an elevated temperature condition, the pip cap  1048  and pin  1054  become unsupported, which causes the cross support member  1058  to rotate off of the detents  1057  and causes the compression spring  1056  to push the cross support member  1058  outwardly toward the fire sprinkler head  1040 . The movement of the cross support member  1058  toward the fire sprinkler head applies a load to the tie  1020 , thereby tensioning the tie  1020  and pulling on a valve catch to open the valve. 
     The engagement action of a dry sprinkler according to yet another embodiment of this invention is illustrated in  FIGS. 17A and 17B , engagement action  1855 . As with other embodiments discussed above, the engagement action  1855  is designed to be used with a reducer  1838  and a sprinkler head  1840  that includes a thermally responsive element  1842 , a pip cap  1848 , a spacer  1841 , and a body  1847 . The lower end of the conduit  1810  of the dry sprinkler is received and retained within the upper end of the reducer  1838 . 
     Also, the engagement action  1855  is designed to be used with a tie that is slidably encased by a sheath, as illustrated in  FIGS. 16A-16C  and discussed below. The sheath  1830  (and the tie  1820 ) can be offset from the vertical axis of the conduit  1810  and the reducer  1838 , at least at the junction of the conduit  1810  and the reducer  1838 . 
     An enlarged member, such as a cylinder  1896 , is affixed to the lower end of the sheath  1830 . The cylinder  1896  includes a circular groove  1893 . Similarly, an enlarged member, such as a cylinder  1895  with a circular groove  1892 , is affixed to the lower end of the tie  1820 . 
     The engagement action  1855  includes a tubular support cap or bushing  1872  defining an orifice  1873 , a compression spring  1856 , and a detent ring  1857  received in a slot or groove  1899  in the inner wall of the reducer  1838 . 
     The tubular support cap  1872  includes a circumferential ledge  1898  and a slot  1897 . The slot  1897  receives the cylinder  1895 . 
     When the dry sprinkler is in the inactive state with the thermally responsive element  1842  intact, the spacer  1841  supports tubular support cap or bushing  1872 . The compression spring  1856  is in compression between the circumferential ledge  1898  and the detent ring  1857 . The force of the compression spring  1856  is resisted by the thermally responsive element  1842 . 
     The cylinder  1896  is held in place as follows. The spring clip  1894  is placed in the groove  1893  of the cylinder  1896  such that the free ends of the spring clip  1894  are received between the detent ring  1857  and the top end of the compression spring  1856 . The force of compression spring  1856  pushes the free ends of the spring clip  1894  against the detent ring  1857 , and thus retains the spring clip  1894  and the cylinder  1896  in place. 
     In other embodiments, other apparatus and methods can be employed to retain the cylinder and the cable sheath in place. 
     The cylinder  1895  is “attached” to the engagement action  1855  by a spring clip  1891  and the force of the compression spring  1856  on the spring clip  1891 . Specifically, the spring clip  1891  is placed in the groove  1892  of the cylinder  1895  such that its free ends are received between the circumferential ledge  1898  and the lower end of the compression spring  1856 . The force of compression spring  1856  pushes the free ends of the spring clip  1891  against the circumferential ledge  1898 , such that the spring clip  1891  and the cylinder  1895  move with the circumferential ledge  1898 . 
     In other embodiments, other apparatus and methods can be employed to “attach” the cylinder and the lower end of the tie to the engagement action. 
     As shown in  FIG. 17B , when the thermally responsive bulb  1842  reacts to an elevated temperature condition, the pip cap  1848  and the spacer  1841  are no longer maintained in place by the thermally responsive bulb  1842 . The compression spring  1856  pushes the tubular support cap or bushing  1872  downward until the lower surface of the circumferential ledge  1892  of the tubular support cap  1872  engages the top surface of a ledge  1890  of the reducer  1838 . 
     Because the spring clip  1891  is affixed to the cylinder  1895  and the ends of the spring clip  1891  are fixedly received between the lower end of the compression spring  1856  and the circumferential ledge  1898 , the cylinder  1895  is also driven downward. The movement of the cylinder  1895  downward first tensions the tie  1820  and then causes the tie  1820  to open the valve at the uppermost end of the tie  1820 . The sheath  1930  remains largely stationary because it is retained between the detent ring  1957  and the top of the compression spring  1856 . 
     While, in this embodiment, the sheath  1830  and tie  1820  are attached to the engagement action  1855  by cylinders and spring clips, any other attachment mechanisms can be used to fixedly attach (1) the sheath to the engagement action (or the reducer or another component of the dry sprinkler) such that the sheath does not move when the engagement action is activated and (2) the tie to a component of the engagement action that moves when the engagement action is activated. 
     As discussed above, the first end of the tie in each of the above embodiments is operably coupled to the valve by a valve catch that is configured to allow or cause the valve to move to an open state and preferably maintain the valve in the open state once the tie is engaged. In general, the valve can be biased into a closed state (e.g., biased by interference or by mechanical energy) in which fluid does not flow through the valve. The valve has an open state in which the bias is removed and fluid is allowed to flow through the valve. The valve catch can be operable to translate the load applied to the tie to release the valve bias to open the valve, as well as to maintain the valve in an open position. Exemplary embodiments illustrating the operation of the valve and valve catch are described below in connection with  FIGS. 11A-15B . 
       FIGS. 11A-11C  illustrate the valve  1160  and valve catch  1170  according to one embodiment of a dry sprinkler. In this embodiment, both the valve  1160  and the valve catch  1170  are positioned proximate to the first end  1125  of the conduit  1110 . In dry sprinklers, the valve is generally positioned toward the first end (fluid inlet) of the sprinkler that is connected to the branch line. In the illustrated embodiments, the valve is positioned near the first end, which will allow the substantial majority of the dry sprinkler to be maintained in a dry state during normal operation (i.e., when the thermally responsive element remains intact, i.e., unreacted). 
       FIG. 11A  is an exploded view that illustrates the parts of the valve catch  1170  and the valve  1160 . The valve  1160  is located at valve opening  1181  near the first end of the conduit. As shown in  FIG. 11B , the valve opening  1181  is closed by the cap  1182  and sealing ring  1165 . The cap  1182  and valve housing  1167  are supported on pin  1187 . The valve catch  1170  includes valve catch housing  1190  that supports rotation pin  1186  and hook  1183 . The valve catch housing  1190  can be supported or secured within the conduit  1110  by any suitable structure. The valve catch housing  1190  includes an elongate groove  1192  that accommodates pin  1187 , and the pin  1187  is movable within the elongate groove  1192 . The groove  1192  extends in a direction along the length of conduit  1110 . 
     As can be seen in  FIG. 11B , when the valve is in the closed state, the pin  1187  is positioned at an upper end of the groove  1192 . When the valve is in the closed state, the pin  1187  is supported in the upper end of groove  1192  by a rotatable hook  1183 . The rotatable hook  1183  has a portion that extends underneath and contacts a lower portion of pin  1187  thereby supporting the pin  1187  and the cap  1182  in position that maintains the valve in a closed state. The hook  1183  is rotatably supported with respect to the housing  1190  about rotation pin  1186 . The hook  1183  includes a groove  1184  that extends along the perimeter of hook  1183  and guides the tie  1120  around the hook perimeter. 
       FIG. 11C  illustrates a state where tie  1120  is engaged by an engagement action in response to the thermally responsive element reacting to an elevated temperature condition. The engagement action applies a downward load to the tie  1120 . In that state, the tie  1120  causes the hook to rotate clockwise (from the perspective of  FIGS. 11B and 11C ) around rotation pin  1186 . When the hook  1183  rotates beyond a certain point, the pin  1187 , the housing  1167 , and the cap  1182  become unsupported in the upper portion of groove  1192  and are pushed downward (in  FIG. 11C ) by the force of gravity and/or the fluid pressure that is incident on the valve  1160 . This pushes the sealing member (cap  1182  and sealing ring  1181 ) out of valve opening  1181  and thereby moves the valve  1160  into an open position. As can be seen in  FIG. 11C , the cap  1182  can rotate 90 degrees by the force of torsion spring  1185 . The tie  1120  is thereby operably coupled to the valve to allow the valve to open when the tie is engaged. Forming the valve and the valve catch so that the cap rotates out of the way of the fluid can prevent the cap from becoming lodged within the conduit and can thereby prevent blockage of the fluid flow in the event of a fire. 
       FIGS. 12A-12B  are partial cut-out views illustrating a valve catch  1270  of another embodiment that is provided at a first end portion  1225  of a dry sprinkler.  FIG. 12A  illustrates the valve  1260  in a closed position and  FIG. 12B  illustrates the valve components in an open position. The valve  1260  includes cap  1282  and sealing ring  1265  that form a sealing member. The cap  1282  and sealing ring  1265  are rotatably supported on housing  1267  and are rotationally biased by torsional spring  1287 . 
     The valve catch  1270  includes a compression spring  1213 , retention ring  1257 , support balls  1233 , and outer housing  1277 . The support balls are positioned in groove  1235  and extend partially through housing  1277 . As can be seen in  FIG. 12A , the balls  1233  support the housing  1267 . The balls  1233  are held in place by retaining ring  1257  that is provided with groove  1234  to accommodate the support balls  1233 . The retaining ring  1257  can optionally be held in place by a compression spring  1213 . The retaining ring  1257  can also be held in place by sizing and arranging the balls  1233  and/or groove  1234  so that the balls are pressed against the retaining ring  1257  with sufficient force to hold it in place. The tie  1220  is connected to the retaining ring.  FIG. 12A  illustrates the sprinkler when the tie  1220  is in an unengaged state and when the valve catch  1270  has not been triggered. 
       FIG. 12B  illustrates the valve catch in an activated state. In  FIG. 12B , tie  1220  is tensioned in an engaged state and pulls the retaining ring  1257  with a force that overcomes the force of compression spring  1213 . The tie  1220  pulls the retaining ring  1257  downwardly, which releases support balls  1233 . Once the support balls  1233  are released, the housing  1267  moves downwardly which causes the cap  1282  and sealing ring  1265  to rotate 90 degrees from the force of torsion spring  1287 , thereby opening the valve. 
       FIGS. 13A-13B  are partial cut out views illustrating a valve catch  1370  that is provided at an end portion  1325  of a dry sprinkler.  FIG. 13A  illustrates the valve  1360  in the closed positions and  FIG. 13B  illustrates the valve  1360  in the open position. The valve components are similar to those in  FIG. 12 , and include cap  1382  that is rotatably supported on housing  1367 . The cap  1382  is rotatably biased by torsion spring  1387 . The valve catch  1370  includes pivot arms  1337  that have flange portions  1347 . The flange portions  1347  support the housing  1367  and keep the valve in a closed position. The pivot arms  1337  are provided on the outer circumference of housing  1377 , which includes holes or cutouts for receiving the flange portions  1347  at one end and the rotating end portions  1355  at the other end. The pivot arms  1337  are biased outwardly by the force of fluid pressure that presses the housing  1367  on the flange portions  1347  of the pivot arms  1337 . The pivot arms  1337  are held into place by retaining ring  1357 , which is supported by compression spring  1313 . The retaining ring  1357  is connected to the tie  1320 .  FIG. 13A  illustrates the sprinkler when the tie  1320  is in an unengaged state and when the valve catch  1370  has not been triggered. 
       FIG. 13B  illustrates the valve catch  1370  in an activated state when the tie  1320  is engaged. In  FIG. 13B , the tie  1320  is tensioned in an engaged state and pulls the ring  1357  downwardly. Once the ring  1357  is pulled down over the rotation ends  1355  of the pivot arms  1337 , the downward force from the housing  1367  on the flange portions  1347  of the pivot arms  1337  causes the rotation ends  1355  of the pivot arms  1337  to rotate outwardly from housing  1377 . This, in turn, causes the housing  1367  to move downwardly, which allows the cap  1382  to rotate by the force of torsion spring  1387 , thereby opening the valve. 
       FIGS. 14A-14B  are cross-sectional views illustrating a valve catch  1470  that is provided at a first end portion  1425  of a dry sprinkler  FIG. 14A  illustrates the valve  1460  in the closed position and  FIG. 14B  illustrates the valve  1460  in the open position. The valve components are similar to those in  FIG. 13 , and include cap  1482  that is rotatably supported on housing  1467  about pin  1488 . The cap  1482  is rotatably biased by a spring (not pictured). The valve catch  1470  includes a long pivot arm  1437  that rotates about pivot point  1456  and a short pivot arm  1438  that rotates about pivot point  1466 . The long pivot arm  1437  includes an end portion  1447  and the short pivot arm  1438  includes flange portion  1448 . The pivot arms  1437 ,  1438  are provided on the outer circumference of housing  1477 . When the valve  1460  is in the closed position, the end portion  1447  of the long pivot arm  1437  rests on the flange portion  1448  of the short pivot arm  1438  so that the long pivot arm  1437  is supported in a position that it extends transversely across the conduit  1410 . In this position, the long pivot arm  1437  supports the housing  1467  of the valve  1460 . The force of the fluid incident on valve  1460  applies a force on the housing  1467  and long pivot arm  1437 , which creates a rotation moment on the short pivot arm  1438 . 
     The valve catch  1470  includes retaining ring  1457 , which prevents the short pivot arm  1438  from rotating outwardly when the valve  1460  in a closed position. The retaining ring  1457  is supported by compression spring  1413 . The tie  1420  is connected to the retaining ring  1457 .  FIG. 14A  illustrates the sprinkler when the tie  1420  is in an unengaged state and when the valve catch  1470  has not been triggered. 
       FIG. 14B  illustrates the valve catch  1470  in an activated state when the tie  1420  is engaged. In  FIG. 14B , the tie  1420  is tensioned in an engaged state and pulls the ring  1457  downwardly. Once the ring  1457  is pulled down over the rotation ends of the short pivot arm  1438 , the force that the housing  1467  exerts on the long pivot arm  1437  causes the end of the short pivot arm  1438  to rotate outwardly from housing  1477 , which causes the long pivot arm  1437  to rotate clockwise from the perspective of  FIGS. 14A and 14B . This, in turn, causes the housing  1467  to move downwardly, which allows the cap  1482  to rotate 90 degrees about pin  1488 , thereby opening the valve. 
       FIGS. 15A and 15B  are cross-sectional views illustrating a valve catch  1570  that is provided at an end portion  1525  of a dry sprinkler.  FIG. 15A  illustrates the valve  1560  in a closed position and  FIG. 15B  illustrates the valve  1560  in an open position. In  FIG. 15A , the valve catch  1570  includes clip  1521 , lever  1551 , and main pivot  1533 . The cap  1582  and the sealing member  1565  are rotatably supported within the conduit by main pivot  1533 . The lever  1551  is rotatably supported with respect to the conduit  1510  at pivot point  1549 . In  FIGS. 15A and 15B , the pivot point  1549  is located on the cap  1582  so that the lever  1551  is pivotally connected to cap  1582  at pivot point  1549 . In a closed position, the cap  1582  is supported on the lever  1551  near pivot point  1549 . In an alternative structure, the pivot point  1549  can be a pin that is supported on the conduit inner wall, so that the lever  1551  does not pivot on the cap  1582 . 
     The lever  1551  includes an extending portion  1547  that is supported on notch  1546  of the sprinkler housing when the valve  1560  is in a closed state. On the other end, the lever  1551  includes a clip end  1562  that is held by clip  1521  when the valve  1560  is closed. The valve catch  1570  also includes a second clip end  1561  that is held by the clip  1521  when the valve  1560  is closed. The clip  1521  holds the lever  1551  in a horizontal position and prevents the lever  1551  from rotating about pivot point  1549 . The clip  1521  is connected to tie  1520 . 
       FIG. 15B  illustrates the valve catch  1570  in an activated state when the tie  1520  is engaged. In  FIG. 15B , the tie  1520  is tensioned in an engaged state and pulls the clip  1521  downwardly off of the clip ends  1561 ,  1562 . When the clip  1521  is removed, the lever  1551  rotates about pivot  1549  which causes the extending portion  1549  to lift off of the notch  1546 . This causes the cap  1582  to rotate about main pivot  1533  and open the valve. 
     The flexible dry sprinklers can optionally include a tie sheath as shown in  FIGS. 16A-16C . The flexible dry sprinkler  1650  can be provided with tie sheath  1630  that surrounds the tie  1620  over most of the length of tie  1620 . The tie sheath  1630  can optionally be positioned centrally within conduit  1610 . The tie sheath  1620  can be used to reduce the amount of slack that is created in tie  1620  when the flexible conduit  1610  is bent. Some slack may be desirable in the tie  1620  to prevent the tie  1620  from accidentally engaging and opening the valve when the conduit is bent or moved. However, when the conduit  1610  is bent to position the fire sprinkler head  1640 , the amount of slack in tie  1620  will generally increase because the distance that the tie  1620  is required to span within the conduit  1610  to extend from the valve catch at one end to the engagement action at the other end becomes shorter as the conduit  1610  is bent, whereas the free length of the tie  1620  of course remains the same. The tie sheath  1630  holds the tie  1620  centrally within conduit  1610  which reduces the amount of slack that is introduced into the tie  1620  when the flexible conduit  1610  is bent, and thus prevents the need to eliminate extra slack when the engagement action is triggered. 
     The tie sheath  1630  can be a hollow tubular member that extends within the conduit substantially from the valve catch to the engagement action. The tie sheath  1630  can extend substantially the length of the conduit, i.e., at least 80% of the conduit length. The tie sheath  1630  can have a cross-sectional dimension (e.g., diameter) that is less than half of the cross-sectional dimension of the flexible conduit  1610 . 
     As shown in  FIG. 16B , the tie sheath  1630  can be coupled to cross bar member  1632  that centrally positions the sheath  1630  within the conduit  1610  proximate to the second end  1635 . Similarly, as shown in  FIG. 16C , the tie sheath  1630  can be coupled to a second cross bar member  1634  that centrally positions the sheath  1630  within the conduit  1610  proximate to the first end  1625 . The tie sheath  1630  can be made of a flexible resilient material, e.g., a resilient polymer or rubber that maintains a constant length when the flexible conduit  1610  is bent by deforming/bending to accommodate the bends of the conduit  1610  as illustrated in  FIG. 16A . 
     As stated,  FIGS. 18A-19C  illustrate a valve catch of another embodiment of this invention, valve catch  1970 . The valve catch  1970  is designed to be used with a valve  1960  and an end cap  1950 . The end cap  1950  is attached to the top end of the conduit  1910 . 
     The end cap  1950  includes an internal fluid passageway  1952  and a top ring  1951  that extends inwardly. The top ring  1951  forms a valve opening  1981  and a ledge  1982 . 
     The valve catch  1970  is configured to alternatively (1) retain the valve  1960  such that it blocks the valve opening  1981  and (2) permit the valve  1960  to be moved from blocking the valve opening  1981 . The valve  1960  includes a cap  1962  and a sealing ring  1965 . The sealing ring  1965  engages the ledge  1982  when the valve  1960  blocks the valve opening  1981 . 
     The valve catch  1970  is also designed to be used with a tie that is slidably encased in a sheath, as illustrated by  FIGS. 16A-16C  and discussed above, such as a tie  1820  slidably encased in a sheath  1930 . An enlarged member, such as a cylinder  1931 , is affixed to the top end of the sheath  1930 , and an enlarged member, such as a cylinder  1921 , is affixed to the top end of the tie  1920 . 
     The valve catch  1970  includes a support  1901 , a threaded member  1902 , a horizontal support bar  1903  and a vertical support bar  1904  (the references to “horizontal” and “vertical” are in applications in which the dry sprinkler is a pendant dry sprinkler as shown in  FIGS. 18A-18C —the “horizontal” and “vertical” members may have different orientations in other applications). 
     The support  1901  includes a body  1905 , supporting arms  1906 , an orifice  1907 , an orifice  1908 , and an orifice  1909 . The supporting arms  1906  are integral with the body  1905  and extend upwardly and outwardly to engage the inner surface of the end cap  1950  and the lower surface of the ledge  1892 . 
     The threaded member  1902  threadedly engages the orifice  1907  and has a pointed end  1911 . The position of the threaded member  1902  can be adjusted relative to the body  1905  by rotating the threaded member  1902 . 
     The cylinder  1931  is received in the orifice  1908 . The cylinder  1931  includes a reduced diameter section  1932 . A spring clip  1933  is placed on the reduced diameter section  1932 . The free ends of the spring clip  1933  extend into the orifice  1909  to fixedly attach the cylinder  1931 , and thus the sheath  1930 , to the body  1905 . In other embodiments of this invention, the sheath can be attached to the valve catch by any other type of fastening mechanism 
     The horizontal support bar  1903  includes a circular opening  1925  at one end, and a groove  1926  and a dimple  1927  at the other end. The groove  1926  and the dimple  1927  are aligned, but in opposite faces of the horizontal support bar  1903 . 
     The cylinder  1921  includes a reduced diameter section  1922 . The reduced diameter section  1922  is received in circular opening  1925 , to affix the cylinder  1921 , and thus the tie  1920 , to the horizontal support bar  1903 . That is, the upper and lower surfaces of the end of the horizontal support bar  1903  that includes the circular opening  1925  engage the lateral faces of the cylinder  1921  that form the reduced diameter section  1922 . In other embodiments of this invention, the tie  1920  can be “attached” to the horizontal support bar  1903  by any other type of engagement mechanism. 
     The tip of the pointed end  1911  of the threaded member  1902  is received in the dimple  1927 . The bottom of the vertical support bar  1904  is received in the groove  1926 . 
     The vertical support rod  1904  extends between the horizontal support bar  1903  and the valve cap  1962 . The top end of the vertical support rod  1904  is received in a groove  1966  in the bottom of the valve cap  1962 . 
     When the valve catch  1970  retains the valve  1960  in the “closed” position, i.e., blocking the valve opening  1981  such that fluid cannot pass through the valve opening  1981 , there is a fluid force on valve  1960 . The horizontal support bar  1903  is held in place by being sandwiched between the pointed end  1911  of the threaded member  1902  and the lower end of the vertical support bar  1904 . 
       FIG. 18C  illustrates the valve catch  1970  when the tie  1920  is pulled downwardly. When the tie  1920  is pulled downwardly, the cylinder  1921  is pulled downwardly. The sheath  1930  remains in place, due to its connection to support  1901 . 
     Because the end of the horizontal support bar  1903  with the circular opening  1925  engages the cylinder  1921  by the engagement of the reduced diameter portion  1922  and the circular opening  1925 , the downward movement of the cylinder  1921  pulls that end of the horizontal support bar  1903  downward, which upsets the equilibrium at the other end of the horizontal support bar  1903 . That causes the vertical support bar  1904  to become dislodged. When the vertical support bar  1904  is dislodged, the valve cap  1962  is forced from its “closed” position by the fluid pressure on the valve cap  1962 , which permits fluid to flow through the valve opening  1981 . 
     A screen  1975  can be provided in the conduit  1910  to prevent the horizontal support bar  1903 , the vertical support bar  1904 , and/or the valve cap  1962  from passing through the conduit  1910 . 
     Each of the valves and valve catches described above can be used in connection with any other embodiment, including any of the engagement actions, ties and/or tie sheaths described above. The type of valve and valve catch is likewise not particularly limited, and a person of ordinary skill in the art would understand that alternative structures would be operable to control the flow of fluid through the conduit. Moreover, although the valve is illustrated to be positioned within the conduit, the valve can be configured to be placed outside of the conduit upstream of the fluid inlet end of the conduit, for example, within the branch line. 
     The dry sprinklers described herein can be used with fire suppression systems to provide fire protection in unheated or refrigerated spaces. In some embodiments, the portion of the dry sprinkler that is upstream of the valve can be “wet.” The portion of the dry sprinkler that includes the valve can be positioned in a heat-controlled space where the temperature is controlled so that it does not drop below a predetermined temperature. For example, the heat-controlled space can be controlled so that the temperature does not drop below 70° F., below 40° or below freezing. The “dry” portion of the sprinkler that is positioned downstream of the valve can be subjected to lower temperature conditions because there is no risk that the fire suppression fluid will freeze and rupture the conduit or otherwise disrupt the normal operation of the sprinkler. Thus, in some embodiments, the portion of the dry sprinkler that includes the fire sprinkler head is located in an unheated space where the temperature is not controlled. Such unheated spaces may include garages, attics, outdoor walkways, breezeways, parking garages, balconies, decks, loading docks, ducts, and the like. In still other embodiments, the portion of the dry sprinkler that includes the fire sprinkler head can be located in a refrigerated space where fire protection is desired (e.g., such as freeze lockers or walk-ins) and where temperatures are maintained at near or below a freezing temperature. 
     In other embodiments, the entire dry sprinkler can be located in unheated or refrigerated space if the flow of water is stopped upstream of the valve, e.g., at a main control valve. In this configuration, the entire sprinkler and connecting branch line remain dry and only the portion of the pipe network upstream of the control valve is wet. The control valve can then be triggered to open in the presence of a fire by a smoke detector or heat activated sensor. 
     While the disclosed dry sprinklers, sprinkler systems, methods of operation and methods of installing have been described in conjunction with exemplary embodiments, these embodiments should be viewed as illustrative, not limiting. It should be understood that various modifications, substitutes, or the like are possible within the spirit and scope of the disclosure.