Patent Description:
A dry pipe sprinkler system or pre-action system comprises a fire suppression system that is typically used in structures and areas that are oftentimes unheated and subject to freezing temperatures. The dry pipe sprinkler system includes a network of pipes including branch lines servicing sprinkler heads, risers, and feed mains for delivering water from a water supply to the branch lines. Under normal conditions, this network of pipes contains a pressurized gas, such as air or nitrogen, which holds closed a dry pipe valve that connects the main supply pipes of main feeds of the sprinkler system to the water supply. When heat from a fire opens a sprinkler, the compressed gas is released from the system. The resulting drop in pressure causes the dry pipe valve to open, or trip, thereby releasing water into the main supply lines or main feeds.

When the network of pipes is filled with the pressurized gas and the ambient temperature lowers, condensate can collect in the network of pipes. If the condensate builds up in the system, then there is a risk that the condensate will freeze in the pipes. Freezing condensate can cause pipes to leak or burst, or inhibit the flow of water through the branch lines in the event of fire. For this reason, dry pipe systems often include one or more condensate collector arrangements (sometimes called an "auxiliary drain") which collect condensate from the network of pipes. These auxiliary drains are typically located at low points of the dry pipe system and usually include a drainage valve and a shut-off valve connecting the auxiliary drain to a low point. An auxiliary drain is drained of condensate by first closing the upper valve. This prevents pressurized gas from exiting the system when the auxiliary drain is being drained. The drain valve is then opened and condensate is drained from the auxiliary drain. Then the drain valve is closed again and the upper valve is reopened to again allow condensate to be collected.

A fully open or ruptured auxiliary drain will allow the compressed air inside of the dry system to rapidly vent. This will falsely trip the dry valve, allowing pressurized water to enter the dry portion of the system and a potentially damaging high flowrate will spill out of the open/broken auxiliary drain. In addition to occupant inconvenience, a compromised auxiliary drain can result in thousands of dollars in damage and repair costs plus, hours of maintenance/service time to restore the system to normal operation.

<CIT> discloses an assembly having an auxiliary drain with a level switch, housed in an insulated cabinet with a heater. The heater monitors the temperature in the cabinet and turns on and off as needed to keep the accumulated condensation in the auxiliary drain from freezing. When the amount of water collected reaches a certain volume the level switch will activate and an audible and/or visual alert can be given that the auxiliary drain needs attention. <CIT> presents a dehumidification device of air within a dry sprinkler system. The dehumidification device comprises a condensate collecting container with a discharge valve which may be opened when the fill level exceeds a limit value, and the collected condense is discharged. <CIT> relates to an apparatus for draining a sprinkler system, comprising a condensate reservoir for collecting condensation from a sprinkler system and a programmable controller for discharging the condensation collected in the sprinkler system.

One of the factors working against an automatically draining auxiliary drain is the fact that building code currently requires that the outlet of an auxiliary drain terminate in either a cap or a plug. Typically, auxiliary drains have been located throughout a structure with little concern for incorporated draining, basically a maintenance worker goes around with a bucket or if temperatures are warm enough just dumps the contents of the auxiliary drain out onto the floor of the structure, giving a distinct rust color staining on the floor and walls near the auxiliary drain. However, as systems become more sophisticated and the desire for automation increases, it is anticipated that relevant building codes will be altered or Authority Having Jurisdiction's (AHJ's) will allow auto draining as long as accommodations have been made to drain the water safely so as not to cause a potential slip-and-fall situation.

In accordance with the above, it would be desirable to have a system for maintaining integrity of a dry pipe system in a heated cabinet with a mechanical drain trap and a Y-strainer, and an optional a flow restrictor valve.

In accordance with an aspect, a system is disclosed for maintaining the integrity of a dry pipe sprinkler system, comprising: an auxiliary drain including a main collection pipe; a heater having a bracket configured to attach the heater to the main collection pipe of the auxiliary drain, the bracket including a deflector configured to direct heat from the heater onto the main collection pipe; and a self-draining apparatus configured to receive excess water from the auxiliary drain.

The self-draining apparatus includes: a Y-strainer in communication with a side port of an upper portion of the auxiliary drain, the Y-strainer configure to receive the excess water from the main collection pipe of the auxiliary drain; a drain trap arranged in parallel to the auxiliary drain and in communication with the Y-strainer, the drain trap having a float configured to release water from the drain trap upon the float lifting off a seat within the drain trap; and a drain tube extending from a lower portion of the drain trap and configured to receive the water released from the drain trap.

In accordance with an aspect not encompassed by the wording of the claims but considered as useful for understanding the invention, the self-draining apparatus includes a programmable logic controller configured to receive a signal from a level switch within the auxiliary drain when the excess water is detected in the main collection pipe of the auxiliary drain; and an automatic drain on a lower portion of the auxiliary drain, the automatic drain including a plurality of valves, each of the plurality of valves configured to receive signal from the programmable logic controller to release at least a portion of the excess water within the auxiliary drain though a drain pipe connected to the automatic drain.

In accordance with another aspect, a flow restrictor valve is disclosed, the flow restrictor valve comprising: a plunger configured to be held in an open position by a compression spring, the open position configured to allow a liquid or gas to flow through the flow restrictor valve and a closed position in which a flow of the liquid or gas generates a velocity sufficient to cause the compression spring to compress and engage an outer edge of the plunger with a seat of a retaining member to prevent the flow of the liquid or gas through the flow restrictor valve.

In accordance with a further aspect, a method is disclosed for maintaining the integrity of a dry pipe sprinkler system, comprising: providing an auxiliary drain including a main collection pipe; attaching a heater having a bracket to the main collection pipe of the auxiliary drain, the bracket including a deflector configured to direct heat from the heater onto the main collection pipe; and releasing excess water from the auxiliary drain with a self-draining apparatus, the self-draining apparatus configured to receive the excess water from the auxiliary drain.

Set forth below with reference to the accompanying drawings is a detailed description of embodiments of a system for maintaining integrity of a dry pipe system in a heated cabinet with a mechanical drain trap and a Y-strainer, or a programmable logic controller with automatic valves, and an optional flow restrictor valve and representing examples of the disclosed system for maintaining integrity of a dry pipe system in the heated cabinet with the mechanical drain trap and the Y-strainer, the programmable logic controller with the automatic valves, and the flow restrictor valve, wherein the embodiments including the programmable logic controller are not encompassed by the wording of the claims but considered as useful for understanding the invention.

In accordance with an exemplary embodiment, an auxiliary drain and/or condensate collecting system <NUM> is disclosed that can be either fully or semi-automated, and can reduce the possibility of human error inherent with the unskilled maintenance personnel typically tasked with maintaining the auxiliary drains. With current commodity type auxiliary drains there is no way of knowing how much condensation has accumulated and the drains lack the ability to alert personnel of their status and therefore to prevent freezing they require constant attention.

<FIG> is a front view of an auxiliary drain and/or condensate collecting system <NUM> in accordance with an embodiment disclosed here. <FIG> are a top view, a front view, and a side view of the cabinet <NUM> for the auxiliary drain and/or condensate collecting system <NUM> as shown in <FIG>. As shown in <FIG>, <FIG>, the system <NUM> includes a cabinet <NUM> comprised of a housing <NUM> with a door <NUM> hinged, for example, on a piano hinge <NUM>. In accordance with an exemplary embodiment, the housing <NUM> is configured to house an auxiliary drain <NUM>, a heater <NUM> having a deflector plate <NUM>, and a self-draining apparatus, for example, a mechanical drain trap <NUM>, a second drain line (i.e., drain tube) <NUM>, a Y-strainer <NUM>, and an electrical enclosure <NUM>.

The housing <NUM> and the door <NUM> may be made of steel and may be insulated with a foil faced foam board insulation to help retain heat. In accordance with an embodiment, the insulation has a thickness, for example, of ¼ inch to ¾ inch, for example ½ inch. (<NUM> inch = <NUM>) The housing <NUM> may include a plurality of tabs <NUM>, <NUM>, <NUM>, <NUM> (<FIG>) for mounting the housing <NUM> upon a concrete pillar, wall or other surface as may be desired or required. The door <NUM> can include a key lock <NUM> (<FIG>) and attendant latch <NUM> on the inside of door <NUM>.

Within housing <NUM>, the auxiliary drain <NUM> can be mounted to housing <NUM>, for example, with a pair of U-bolts. Extending from the top of housing <NUM> is input pipe <NUM>, which is connected in turn to a dry pipe sprinkler system (<FIG>). Upper valve <NUM> controls input pipe <NUM> which then leads into the auxiliary drain <NUM> (i.e., condensate collection area) via coupling <NUM>. As shown in <FIG>, a lower drainage valve <NUM> which, when opened, provides for drainage from the auxiliary drain <NUM> through drain pipe <NUM>. The drain pipe <NUM> may include a cap <NUM>, which can be, for example, secured or screwed (i.e., threaded cap) or other connection method onto the end of the drain pipe <NUM>.

In accordance with an exemplary embodiment, the input pipe <NUM> travels into the housing <NUM> via pass-through <NUM>, which can be sealed to prevent nuisances such as bees or other unwanted intruders from entering. There may or may not be a seal, a seal may be water resistant or proofed, other protections as known in the art, etc. may be used as desired in various embodiments. Drain pipe <NUM> travels through pass-through <NUM> which is also sealed in a similar manner to pass-through <NUM>. The cap <NUM> can be removed to drain the auxiliary drain <NUM>, desirably in an appropriate procedure that maintains pressurization, as is described, for example, in National Fire Prevention Association (NFPA) <NUM> guidelines.

In accordance with an embodiment, the cabinet <NUM> can include a thermometer <NUM> configured to display the temperature inside the housing <NUM> of the cabinet <NUM> though an external dial <NUM> (<FIG>) on the door <NUM>. In various embodiments that temperature may be monitored and an alarm be set to provide warning if the inside temperature fell below a predetermined level. That alarm may be local and/or be sent to a central location as desired. It should be noted that, although exemplary embodiments contain an auxiliary drain <NUM>, it might be desired in other embodiments to provide a retrofit embodiment to install around an existing auxiliary drain <NUM>.

In accordance with an exemplary embodiment, the auxiliary drain and/or condensate collection system <NUM> can include, for example, a mechanical version (<FIG>), which uses a Y-strainer <NUM> and a drain trap <NUM>. As shown in <FIG>, the drain trap <NUM> can be plumbed in parallel to the main collection pipe (i.e., main condensate collection pipe) <NUM> of the auxiliary drain <NUM> via a side port <NUM> on the main collection pipe <NUM>. As water condensation makes its way through the fire system and down to the auxiliary drain <NUM>, the level of condensation will increase until it reaches the side port <NUM> at which time the condensation will begin to spill over into the drain trap <NUM> after first passing through the Y-strainer <NUM>. In accordance with an embodiment, the Y-strainer <NUM> offers a layer of protection to help prevent suspended debris in the condensate from reaching and potentially clogging the drain trap <NUM>. When enough condensation accumulates in the drain trap <NUM> and Y-strainer <NUM>, a float inside the drain trap <NUM> will lift off of its seat allowing the accumulated water to exit out of the cabinet <NUM>. When enough water drains from the drain trap <NUM>, the float will reseat closing off the exit path and preventing the dry systems pressurized air from escaping the system. In accordance with exemplary embodiment, the amount of condensation being drained by the system <NUM> should be relatively minimal and, a secondary drain line <NUM> connected to a lower portion <NUM> of the drain trap <NUM> can be used, for example, in the form of flexible tubing or the like.

In accordance with an exemplary embodiment, this process will continually repeat as more condensate makes its way to the drain trap <NUM> or until the main collection pipe <NUM> of the auxiliary drain <NUM> is manually drained of condensate through the main drain <NUM>. Since the drain trap <NUM> and/or the Y-strainer <NUM> will maintain a certain amount of accumulated condensation, it can also be of vital importance that the drain trap <NUM> also be protected by the insulated and heated cabinet <NUM>, or else, the drain trap <NUM> would be subject to failure as a result of freezing.

In accordance with an exemplary embodiment, when the auxiliary drain <NUM> is almost completely full, and the drain trap <NUM> can allow relatively small amounts of water to drain from the system <NUM>, a level switch <NUM>, by way of a local buzzer light (i.e. an alarm) <NUM> can alert the user that the auxiliary drain <NUM> needs attention. In accordance with an embodiment, the drain trap <NUM> can provide a level of security to the system <NUM> that eliminates the need for immediate attention.

In accordance with an aspect, the system <NUM> can also include a cabinet heater <NUM> configured to be mounted directly to the main collection pipe <NUM> of the auxiliary drain <NUM>, which can rather easily be installed or removed because with a bracket design that is not tied to the electrical enclosure. Second, an orientation of the heater <NUM> can be used to maximize component life by vertically mounting the heater with a fan of the heater blowing upward into cabinet <NUM>. For example, the mounting bracket <NUM> can improve the orientation of the heater <NUM> in its position to maximize its effectiveness. In accordance with an exemplary embodiment, the mounting bracket <NUM> can include a deflector <NUM>, which directs the warm air flow coming from the heater <NUM> onto the main collection pipe <NUM>. For example, instead of simply warming the air inside of the housing <NUM> of the cabinet <NUM>, the deflector <NUM> of the mounting bracket <NUM> focuses the energy (i.e., heat) of the heater <NUM> onto the main collection pipe <NUM> thereby maximizing the heat transfer into the pipe <NUM>, which can help ensure that the condensate inside of auxiliary drain pipe <NUM> will remain liquid even in the coldest climates.

The cabinet <NUM> also includes an electrical enclosure <NUM>, which contains components for an alarm as well as other components such as circuit protection, a relay and terminal blocks. For example, a local light buzzer <NUM> can extend through recess <NUM> in the door <NUM> of the cabinet <NUM> and provides an audible sound, for example, a buzzer, and light (i.e., a flashing or solid red light) when the main collection pipe <NUM> of the auxiliary drain <NUM> is full of condensate. In other embodiments, it should be noted and as was described above, the alarm may trigger when varying amounts, or any at all, of condensate accumulates. The electrical enclosure <NUM> is at least a NEMA <NUM> enclosure in exemplary embodiments as set forth in the National Electrical Manufacturers Association Standards Publication <NUM>-<NUM>. Conduit (not shown) can provides power to the heater <NUM> and the local light buzzer <NUM>, which in exemplary embodiments is 120V and enters the housing <NUM> through a pass-through (not shown), which can be sealed similarly to the other pass-throughs <NUM>, <NUM>.

In accordance with an exemplary embodiment, the heater <NUM> can be sized appropriately, (for example, a <NUM> Watt (W) heater in tone exemplary embodiments), for example, to provide the interior of housing <NUM> with an air temperature of from approximately, for example, <NUM> to <NUM> (<NUM>°F to <NUM>°F), which may be set by thermostat, be preset, allow for setting during or after installation, be set from a central control area, etc..

It should be noted that exemplary embodiments may provide for centralized control as well, with the alarm settings, drainage, heater and other components being monitored and/or manipulated from a central location. Exemplary embodiments may include as well a test device to confirm the alarm and other components are working correctly, which may as well be local and/or activated and/or monitored from a central location.

<FIG> is front view of the cabinet <NUM> for the auxiliary drain and/or condensate collecting system <NUM> with the door open <NUM> in accordance with another exemplary embodiment not encompassed by the wording of the claims but considered as useful for understanding the invention. As shown in <FIG>, an electrical version of the system <NUM> as shown in <FIG> is disclosed that includes a programmable logic controller <NUM> housed within, for example, the electrical enclosure <NUM>, and a self-draining apparatus comprising an automatic drain <NUM> and a level switch within auxiliary drain <NUM> as disclosed above. In accordance with an exemplary embodiment, the automatic drain <NUM> can include one or more motorized ball valves configured to perform automated draining of an auxiliary drain <NUM>. As disclosed, condensate will slowly accumulate in the main collection pipe <NUM> of the auxiliary drain <NUM>. Eventually, the condensate level will reach the level switch <NUM> at the top of the main collection pipe <NUM>. When this happens, the float will lift as before but, in this case, the level switch <NUM> will close a set of electrical contacts which signal the programmable logic controller <NUM> that the main collection pipe <NUM> is full, which will start the automatic draining cycle of the system <NUM>, for example, with the automatic drain <NUM>. In accordance with an exemplary embodiment, the programmable logic controller <NUM> sequencing can help ensure every valve motion has either reached a fully closed or open position before continuing to the next step. While conducting the drain cycle, the programmable logic controller <NUM> can also activate a local light buzzer <NUM> (i.e., an alarm), and closes a pair of trouble contacts which signal a remote panel that the cabinet <NUM> is executing an automatic drain.

In accordance with an exemplary embodiment not encompassed by the wording of the claims but considered as useful for understanding the invention, once the drain cycle has successfully completed, the local light buzzer <NUM> turns off and the trouble contacts open. In order to also provide an indication that an automatic drain cycle has occurred, one of the electrical enclosure's cover lamps <NUM> can be configured to flash until the system <NUM> is manually reset. If, however, the cycle does not successfully complete, the local light buzzer <NUM> will continue to alarm and the trouble contacts will remain closed. Depending on the anomaly, certain lamps <NUM>, <NUM>, for, example, on the cover of the electrical enclosure <NUM> can flash to provide an indication as to the source of the issue.

The programmable logic controller <NUM> can also offers other, for example, a semi-automatic drain cycle, a drain override cycle and heater monitor. For example, if the end user wishes to drain condensate from the auxiliary drain <NUM> before the main collection pipe <NUM> is full, the user can simply press a drain pushbutton <NUM> provided for example on the cover of the electrical enclosure <NUM>. The programmable logic controller <NUM> can then execute an on demand drain cycle to safely empty its contents without any risk of accidentally opening or closing the valves in the wrong order. Therefore, accidentally tripping the sprinkler system can be prevented even for the most unskilled operator.

In addition, there may be an occasional need to simultaneously open both a system and drain valves, such as when the sprinkler system is being depressurized for service. In accordance with an embodiment, the programmable logic controller <NUM> can be configured to execute this drain override cycle when both cover pushbuttons <NUM>, <NUM> (i.e., drain valve pushbutton <NUM> and drain system pushbutton <NUM>) are simultaneously pressed and held, for example, for approximately two (<NUM>) seconds to four (<NUM>) seconds, perhaps more optimally, for example, for approximately three (<NUM>) seconds. Additionally, instead of a relay timer, the programmable logic controller <NUM> can be coded to activate the local light buzzer <NUM> and close the trouble contacts when the heater <NUM> has been continuously active for more than a few hours.

<FIG> is an illustration of a dry pipe sprinkler system <NUM> in accordance with an embodiment. The dry pipe sprinkler system <NUM> typically includes a network of pipes <NUM> which are in fluid communication with sprinkler heads (not shown). The network of pipes <NUM> is filled with a pressurized gas, e.g., air or nitrogen. As disclosed herein, the dry pipe sprinkler system <NUM> can be used, for example, in parking garages, manufacturing facilities, self-storage facilities, home center garden area and other similar location. As shown in <FIG>, the dry pipe sprinkler system <NUM> can include one or more auxiliary drain and/or condensate collecting systems <NUM> (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) as disclosed herein.

<FIG> are a front view and a side view, respectively of an auxiliary drain <NUM> with a flow restrictor valve <NUM> in accordance with an exemplary embodiment. As shown in <FIG>, a pair of valves <NUM>, <NUM>, for example, a first valve <NUM> (i.e., a system valve) and a second valve <NUM> (i.e., a drain valve) can be provided at an upper portion of the auxiliary drain <NUM> and at a lower portion of the auxiliary drain <NUM>, respectively. The first or system valve <NUM> comprises an inlet which communicates with the flow restrictor valve <NUM> and via the flow restrictor valve <NUM>, the pipes of the dry pipe system <NUM> (<FIG>).

In accordance with an embodiment, the first valve <NUM> can include a valve actuator <NUM> such as a lever or T-handle, which is arranged to rotate about an axis. For example, the first valve <NUM> can be a quarter-turn valve with the valve fully open when the valve actuator is aligned with a longitudinal axis of the first valve <NUM> and with the valve fully closed when the valve actuator has been rotated <NUM> degrees to position the valve actuator generally perpendicular to the longitudinal axis of the first valve <NUM>.

In accordance with an exemplary embodiment, the second valve <NUM> similarly has an inlet in communication with the auxiliary drain <NUM> and an outlet. The second valve <NUM>, like the first valve <NUM>, has a valve actuator <NUM> such as a lever or T-handle which is arranged to rotate about an axis. In an exemplary embodiment, the valve actuator <NUM> extends a predetermined distance from the axis. The second valve <NUM> may be a quarter-turn valve with the valve fully open when the valve actuator <NUM> is aligned with a longitudinal axis of the second valve <NUM> from the inlet to the outlet and with the valve fully closed when the valve actuator has been rotated <NUM> degrees to position the valve actuator generally perpendicular to the longitudinal axis of the second valve <NUM>.

<FIG> is a cross sectional view of the first valve <NUM> and the flow restrictor valve <NUM> along the line VI-VI in <FIG>. As shown in <FIG>, the flow restrictor valve <NUM> has a housing <NUM> and includes an inlet <NUM> and an outlet <NUM>. The housing <NUM> can have, for example, a cylindrical shape or a hexagonal shape. The inlet <NUM> may include a series of internal (e.g., female) threads <NUM> configured to receive a pipe end (not shown) from a pipe of dry pipe system <NUM>. The outlet <NUM> includes a series of external (e.g., male) threads <NUM> configured to be threaded into internal threads (e.g., female) threads of the first valve <NUM>. The inlet <NUM> being in fluid communication with the outlet <NUM> via an interior portion <NUM> of the cylindrical housing <NUM>.

As shown in <FIG>, a plunger (or shuttle) <NUM> is held in the open position by a compression spring <NUM> that allows the flow of a liquid or gas to pass through the valve <NUM> under typical operating conditions. In accordance with an exemplary embodiment, the typical flow rate of the liquid or gas in the system <NUM> is slow enough that it does not have enough velocity to overcome the spring's force so the plunger <NUM> remains in the open position as shown in <FIG>. If there is a break or unintended opening in the plumbing downstream of the flow restrictor valve <NUM>, the flow rate and velocity will suddenly increase. This large increase in velocity will result in a large increase in the force against the plunger <NUM>, overcoming the resistance of the spring <NUM> causing the plunger <NUM> to snap closed against a seat <NUM>, for example, within a fraction of a second. Once closed the plunger <NUM> can be held in the closed position by the now static pressure of the upstream liquid or gas.

<FIG> is a top view of a flow restrictor valve <NUM> in accordance with an embodiment. As shown in <FIG>, the flow restrictor valve <NUM> has an inlet <NUM> with a series of internal (e.g., female) threads.

<FIG> is a side view of the flow restrictor valve <NUM>. As shown in <FIG>, the flow restrictor valve <NUM> has a housing <NUM> and a series of external (e.g., male) threads <NUM> on the outlet end <NUM> of the valve <NUM>. In accordance with an exemplary embodiment, the external threads <NUM> are, for example, <NUM>" NPT (National Pipe Thread).

<FIG> is a bottom view of the flow restrictor valve <NUM>. As shown in <FIG>, the flow restrictor valve <NUM> allows condensate and/or water to flow through a plurality of openings <NUM> within the retaining member <NUM> to the outlet <NUM> of the flow restrictor valve <NUM>.

<FIG> is a cross sectional view of the flow restrictor valve <NUM> along the line VIII-VIII in <FIG> in the open position. The flow restrictor valve <NUM> includes an inlet <NUM> in fluid communication with an outlet <NUM>. The interior portion <NUM> of the valve <NUM> includes a retaining ring <NUM>, an accelerator <NUM>, a spacer <NUM>, an O-ring <NUM>, the plunger <NUM>, a pin <NUM>, and the spring <NUM>. The retaining ring <NUM> is located on an inner surface of the valve <NUM> and configured to retain the accelerator <NUM>, the spacer <NUM>, the O-ring <NUM>, the plunger <NUM> and the spring <NUM> within the interior portion <NUM> of the valve <NUM>. The spacer <NUM> is arranged between a lower edge (i.e., slightly smaller diameter passageway <NUM>) of the accelerator <NUM> and an upper edge of a retaining member <NUM> configured to house the plunger <NUM> and the compression spring <NUM>.

The retaining member <NUM> includes an inner annular side wall <NUM> and a base portion <NUM> having a plurality of openings <NUM> (<FIG>) configured to retain the spring <NUM> and allow condensate and/or water to reach the outlet <NUM>. The retaining member <NUM> also include an inner annular protrusion <NUM>, which extends upward from the base portion <NUM> and provides a platform <NUM> for the spring <NUM> to be compressed downward when the flow restrictor valve <NUM> is in a closed portion.

In accordance with an exemplary embodiment, the spring <NUM> can be enclosed in a protective shroud <NUM> formed by the downstream side <NUM> of the plunger <NUM>. Any contaminated liquid will move past this location and be prevented from depositing on the spring <NUM> because it is not in the condensate's flow path. In addition, the shroud <NUM> will naturally form a protective pocket of captured air which is an important feature because an auxiliary drain <NUM> may be allowed to overfill due to lack of maintenance. If the liquid level reaches the flow restrictor valve <NUM>, the spring <NUM> will remain dry because of this protective air pocket.

<FIG> is a cross sectional view of the flow restrictor valve <NUM> along the line IX-IX in <FIG> in the closed position. As shown in <FIG>, the accelerator <NUM> is an annular member having a slightly smaller diameter passageway <NUM> on a lower portion of the annular member and immediately upstream of the plunger <NUM>. The accelerator <NUM> has an upper diameter <NUM> that is greater than the lower diameter passageway <NUM> to accelerate a flow of water towards the plunger <NUM> to help ensure that the velocity immediately before the plunger <NUM> is high enough to guaranty the force generated is enough to close the plunger <NUM>. In accordance with an exemplary embodiment, any water moving toward the flow restrictor valve <NUM> during a rupture (or fully open AD) will be forced through this slightly restricted passageway <NUM> and naturally accelerate to the point of generating enough force to close the plunger <NUM>. While measurably smaller than the inside diameter of the pipe, the passageway <NUM> of the accelerator <NUM> is still large enough that it will not clog with condensate debris and since there are no sprinklers downstream of the auxiliary drain <NUM>, such that a reduced inside pipe diameter does not compromise the system <NUM>.

In accordance with an exemplary embodiment, the plunger <NUM> includes an upper platform <NUM> having a relatively flat upper surface, an annular side wall <NUM> having a relatively vertical surface parallel with the flow through the valve, a tapered side wall <NUM>, and an annular lower portion <NUM> having a hollow inner portion <NUM>, which is configured to receive and form the protective shroud <NUM> for the spring <NUM>.

As previously mentioned, the condensate which exists in a dry sprinkler system will likely contain corrosion and other clogging debris, which may necessitate the need for a relatively larger passageways through the flow restrictor valve <NUM>. In addition, the failure created by a freeze and break may not be as large as an open valve and it may not be a major rupture such as would be created from a severed natural gas line. In both cases there is a risk of not having enough velocity when needed to overcome the spring's force and close the flow restrictor valve <NUM>. In accordance with an exemplary embodiment, a lighter compression spring <NUM>, for example, which needs less force to close the plunger <NUM> can be used.

<FIG> is a detailed view of the section X of <FIG>. As shown in <FIG>, a sealing interface <NUM> between the plunger <NUM> and a seat <NUM> of the retaining member <NUM> is disclosed that is designed to be an edge contact. Instead of having the same tapered angle, the angle between a lower surface <NUM> of the plunger <NUM> and an upper edge <NUM> of the retaining member <NUM> can differ, for example, by a few degrees, for example, <NUM> degrees to <NUM> degrees, and more perhaps more optimally, <NUM> degrees to <NUM> degrees. In accordance with an embodiment, a taper <NUM> of the seat <NUM> of the retaining member <NUM> is at a steeper angle (i.e., greater angle) than a taper <NUM> of the plunger <NUM>. In accordance with an exemplary embodiment, the difference in tapers <NUM>, <NUM> of the seat <NUM> of the retaining member <NUM> and the plunger <NUM> can cause the sealing force to be focused on an outer edge portion <NUM> of the plunger <NUM> instead of distributing it across the entire sealing face, which not only creates a consistent level of contact force, but it also reduces the likelihood of contamination keeping the two parts from touching each other when there is a buildup on the face of the seat. In accordance with an exemplary embodiment, for example, the edge contact will knife through this debris because the force is focused on a relatively significantly smaller area.

Claim 1:
A system for maintaining the integrity of a dry pipe sprinkler system, comprising:
an auxiliary drain (<NUM>) including a main collection pipe (<NUM>);
a heater (<NUM>) having a bracket (<NUM>) configured to attach the heater (<NUM>) to the main collection pipe (<NUM>) of the auxiliary drain (<NUM>) the bracket (<NUM>) including a deflector (<NUM>) configured to direct heat from the heater (<NUM>) onto the main collection pipe (<NUM>); and
a self-draining apparatus (<NUM>) configured to receive excess water from the auxiliary drain (<NUM>), wherein the self-draining apparatus (<NUM>) comprises:
a Y-strainer (<NUM>) in communication with a side port (<NUM>) of an upper portion of the auxiliary drain (<NUM>), the Y-strainer (<NUM>) configure to receive the excess water from the main collection pipe (<NUM>) of the auxiliary drain (<NUM>);
a drain trap (<NUM>) arranged in parallel to the auxiliary drain (<NUM>) and in communication with the Y-strainer (<NUM>), the drain trap (<NUM>) having a float configured to release water from the drain trap (<NUM>) upon the float lifting off a seat within the drain trap; and
a drain tube (<NUM>) extending from a lower portion (<NUM>) of the drain trap (<NUM>) and configured to receive the water released from the drain trap (<NUM>).