Nipple drinker watering systems are commonly used to provide water to poultry and other small animals. These watering systems involve the use of several branching water supply lines extending the interior length of a house, such as a poultry house. The water supply lines have numerous nipple drinkers attached thereto so that the poultry may obtain water by pecking at the nipples. Stand-tubes are typically provided at various locations along the length of the water supply lines, typically proximate to pressure regulators. The stand-tubes are generally clear and provide a visual indication, with the assistance of a float provided in the stand-tube, of the water pressure level (via water column) in the water supply line at their locations. In order to be effective, the stand-tubes must be able to vent to the outside environment.
Periodically, it may be necessary to flush the nipple drinker watering systems in order to clean out the watering system as material may build up in the watering lines over time due to, for instance, the introduction of sediment from the water source itself or from growers adding material to the water source, such as chlorine or medication. Such build-up of material in the watering system can interfere with proper water flow along the water supply line and may eventually contribute to the malfunction of the nipple drinkers. It may also be necessary to flush the nipple drinker watering systems in order to remove warmer water from the watering system. Removal of warm water from the watering system in order to replace it with cooler water has been found to increase consumption of water by poultry.
Due to the need to flush the systems, the stand-tubes have been outfitted with caps designed to try and prevent leakage out of the stand-tubes during a flushing operation, as well as to prevent the floats from being blown out of the stand-tubes in view of the increased water pressure in the system caused by the flushing. One example of such a cap is shown and described in U.S. Pat. No. 5,136,983. This cap, as well as others, however, have had their own problems. For instance, some caps have had problems with air lock being caused by the seal being formed when it should be allowing air to pass. Other caps have had problems with still allowing leakage to occur after the seal is formed. Other caps have had problems with forming the seal at lower water pressures (e.g., the seal may be formed in caps provided closer to the water source, where the water pressure is typically higher, but not in caps provided distal from the water source, where the water pressure is typically lower). Other caps have designs which allow for air flow both in and out of the assembly, but which allows for unwanted particles to enter the assembly which can cause contamination of the water and which can creates blockages in the cap, thereby potentially causing it to malfunction.
In view of the foregoing, there is a need for a breather cap assembly which overcomes all of the disadvantages of the prior art caps.