Abstract:
Apparatus, methods, and articles of manufacture for maintaining the integrity or pressurization of a dry pipe sprinkler system by preventing damage to auxiliary drains from freezing temperatures are taught. An insulated, heated housing, which may be thermostatically controlled provides a controlled environment about an auxiliary drain, insulated and with a heater. An alarm may be used as well to provide warning if said auxiliary drain retains a predetermined amount of condensate and embodiments may be retrofit about an existing auxiliary drain or be provided with an auxiliary drain for installation upon a dry pipe sprinkler system.

Description:
FIELD OF INVENTION 
       [0001]    The present inventions relate to dry pipe sprinkler systems or pre-action systems and, more particularly, to auxiliary drains, also known as condensate collectors or drum drips. 
       BACKGROUND 
       [0002]    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. 
         [0003]    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 auxiliary drains, also known as condensate collector arrangements or drum drips which collect condensate from the network of pipes. These auxiliary drains are typically located at low points of the dry pipe system and made of a section of larger diameter pipe serving as a condensate collection area, with a smaller diameter pipe at the top and bottom, serving as supply and drain respectively. An upper valve functions as a shut-off valve and a lower valve as a drainage valve. 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 condensate collection area. Then the drain valve is closed again and the upper valve may be reopened to again allow condensate to be collected. 
         [0004]    Whether an auxiliary drain uses a two valve or other arrangement, it may itself be subject to freezing temperatures, and so be in danger of damage from the condensate it collects freezing and/or alternately freezing and thawing. Such damage could lead to failure of the drain and/or the entire system to which the drain is connected. The damage may be limited through a rigorous drainage schedule and/or insulation on the drain, but such measures may be less than ideal and/or poorly implemented. 
       SUMMARY 
       [0005]    The preferred embodiments provide apparatus, methods, and articles of manufacture for maintaining the integrity or pressurization of a dry pipe sprinkler system by preventing damage to auxiliary drains from freezing temperatures. A housing is used for providing a controlled environment about an auxiliary drain, insulated and with a heater. The housing is weather resistant and a locking door is provided for access to the auxiliary drain. 
         [0006]    The heater is thermostatically controlled so that it operates when the ambient temperature is below 40 degrees Fahrenheit. There are various entry ways or penetrations into the housing, for the dry pipe, power for the heater and the like, and these are sealed, minimizing penetration into the interior by nuisances such as bees or other unwanted intruders. 
         [0007]    An alarm, which may or may not include a trigger component as used herein, may be provided as well in order to provide warning if said auxiliary drain retains a predetermined amount of condensate. (for example, a float switch alone, a float switch connected to an alarm, etc.) Embodiments may, as well, provide a housing that is retrofit about an existing auxiliary drain or be provided with an auxiliary drain for installation upon a dry pipe sprinkler system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  shows a view of a preferred embodiment. 
           [0009]      FIG. 2  shows a side view of the embodiment of  FIG. 1 . 
           [0010]      FIG. 3  shows a front view of the embodiment of  FIG. 1 . 
           [0011]      FIG. 4  shows a side view of the embodiment of  FIG. 1 . 
           [0012]      FIG. 5  shows a view of another preferred embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0013]      FIG. 1  shows a preferred embodiment with open door  10 . Door  10  is hinged on piano hinge  15  and closes on housing  20 . Door  10  and housing  20  are made of steel and insulated with ½ inch thick foil faced foam board insulation provided to retain heat, as will be further described below. It should be noted that in this and other embodiments alternative construction may be used as well, all of which are intended to be within the scope of the inventions as defined in the claims herein. 
         [0014]    Tabs  21 - 24  are for mounting upon a concrete pillar, wall or other surface as may be desired, and turning briefly to  FIG. 5  a schematic of a dry pipe sprinkler system is seen as might be present on a floor of a parking garage or the like with embodiments shown at  1 - 6  depending from corners of the system. Returning to  FIG. 1 , key lock  25  and attendant latch  26  is shown on the inside of door  10 . Within housing  20 , auxiliary drain  30  is shown, and is mounted to housing  20  with top u-bolt  28  and bottom u-bolt  29 . Extending from the top of housing  20  is input pipe  31 , which is connected in turn to a dry pipe sprinkler system (not shown.) Upper valve  32  controls input pipe  31  which then leads into condensate collection area  33 . Also at the top of the condensate collection area  33  is float type level switch  35  which allows the unit to fill. As is further described below however if the unit does fill to a preset level, alarm  52  will be triggered. In this and other embodiments, the float type level switch  35  may be set so various levels of condensate may trigger an alarm. Of course, yet other embodiments may dispense with a float type level switch entirely, and an alarm be set to trigger with any amount of condensate. The alarm, it should be noted, may be pre-set, set upon installation, or set during operation, and be set locally and/or from a central location in various embodiments. 
         [0015]    Depending from condensate collection area  33  is lower drainage valve  34  which, when opened, provides for drainage from condensate collector  33  through drain  36 . 
         [0016]    Input pipe  31  travels into housing  20  via pass-through  41 , which, as had been described above, is 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  36  travels through pass-through  46 , which is also sealed in a similar manner to pass-through  41 . Cap  39  can be removed to drain the auxiliary drain  30 , desirably in an appropriate procedure that maintains pressurization, as is described for example in NFPA 25 guidelines. Although the preferred embodiments are within a locking cabinet, and it may not be desired to have an Anti-Trip device, e.g., a wire or plate, other embodiments may use an Anti-Trip device e.g., a wire or plate as desired. 
         [0017]    Thermometer  40  displays the temperature inside the housing  20  though its external dial (not shown.) 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 the preferred embodiments contain an auxiliary drain, it might be desired in other embodiments to provide a retrofit embodiment to install around an existing auxiliary drain. 
         [0018]    Electrical enclosure  50  contains components for an alarm as well as other components such as circuit protection, a relay and terminal blocks. The alarm  52  extends through recess  53  and provides an audible sound (e.g., buzzer) and light when the auxiliary drain 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 alarm enclosure  50  is at least a NEMA 4X enclosure in the preferred embodiments as set forth in the National Electrical Manufacturers Association Standards Publication 250-2003. 
         [0019]    Conduit  66  provides power to a heater (or heating element, the words are used interchangeably herein) (not shown here, see  FIG. 2 ) and alarm  52 , which in the preferred embodiments is 120V and enters the housing  20  through pass-through  67 , which is sealed similarly to the other pass-through  41  and  46 . 
         [0020]    Turning to  FIG. 2 , a side view of the embodiment of  FIG. 1 , a heater  65  is behind enclosure  50 . In the preferred embodiments, the heater is sized appropriately, (e.g., a 60 W heater in the preferred embodiments) and provides the interior of housing  20  with an air temperature of from 40 to 60 degrees F., which may be set by thermostat, be preset, allow for setting during or after installation, be set from a central control area, etc. 
         [0021]    It should be noted that 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. 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. The embodiment of  FIG. 1  shows a test pushbutton  54 , for example, for testing functionality of the alarm system. 
         [0022]    Turning briefly to  FIGS. 3 and 4 , a view of housing  20  with door  10  closed is seen.  FIG. 3  is a front view with thermometer  40 , alarm  52  and key lock  25  visible.  FIG. 4  is a side view of housing  20  with the door closed. 
         [0023]    The foregoing description is provided as an enabling teaching of the inventions in its currently known embodiments. Those skilled in the relevant art will recognize that many changes can be made to the embodiments described while still obtaining the beneficial results of the present inventions. It will also be apparent that some of the desired benefits of the present inventions can be obtained by selecting some of the features of the present inventions without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present inventions are possible and may even be desirable in certain circumstances and are a part of the present inventions. Thus, the following description is provided as illustrative of the principles of the present inventions and not in limitation thereof, since the scope of the present inventions is defined by the claims.