A sprinkler nozzle is a device attached to a water delivery system, such as a pipe or flexible hose, to regulate the flow of water. Sprinkler nozzles attached to most plumbing systems, fire sprinkler systems and irrigation systems are fixed and automatic. Those attached to flexible hoses are usually hand-held and manually operated.
Sprinkler nozzles are equipped with mechanisms that can adjust the flow of water from a single stream to a spray of droplets, depending on the need. A sprinkler nozzle installed on a fire safety system, for example, will be more effective if it disperses water into a spray of droplets that can cover a much wider ares than a single stream of water. Sprinkler nozzles attached to garden hoses, however, might be used for a wide variety of purposes, from garden irrigation to cleaning. A sprinkler nozzle installed on a garden hose, then, should be adjustable to deliver a wide variety of flows.
Fire sprinkler systems were invented in the United States in the 1870s to extinguish factory fires that were so destructive of life and property. Although they were successful at extinguishing fires, they were costly to install. The manufacturers then worked with insurance companies to persuade them to lower fire insurance rates for factories with a fire sprinkler system. The reduced insurance premiums gave factory owners an incentive to make the investment of installing fire sprinklers. Since then, fire sprinklers have become standard equipment in most construction.
The sprinkler nozzle on a modern fire safety system can be closed or open, depending on the type of system. An open system is simply a set of pipes and nozzles that directs water to particular locations when water is sent into the system, either by opening a valve or connecting the system to an outside water source. A closed system is pressurized; that is, water is in the pipes, under pressure, and will be forced out of the system when any of the sprinkler nozzles is opened. The sprinkler nozzles on a fixed system are automatic. When the temperature reaches a certain point, a mechanism is triggered that automatically opens the valve, releasing the water.
Closed systems are generally preferable because they're automatically activated by high heat They're also selectively activated; of all the nozzles in a system, only those actually exposed to high heat will open. Thus, only those locations in jeopardy will be soaked. Open systems, by contrast, generally require human intervention to activate, and upon activation, water is dispersed from all sprinkler nozzles, whether the immediate area is in jeopardy or not.
Irrigation systems use fixed sprinkler nozzles on both stationary and traveling systems. Stationary, or solid-set, systems generally involve systems of pipes, hoses and nozzles, buried or above-ground, with the nozzles aimed at the area to be covered. In systems designed for landscaped areas, the piping is usually buried and the nozzles are designed to be recessed below the surface until forced above-ground by the pressure of the water when the system is activated. Traveling irrigation systems are commonly seen on larger farms, and are made of a superstructure of pipes and hoses, topped by a series of sprinkler nozzles. These structures have wheels that gradually propel the entire device over the area to be covered.
A wide variety of hand-held sprinkler nozzles is available for use with flexible hoses. Some are made for use in applications in factories and other industrial environments, while others are designed for use in household environments, for such tasks as gardening and washing. Some are cylindrical in shape, constructed of brass, and water flow is adjusted by simply twisting the nozzle portion. Others are somewhat pistol-shaped and have a trigger mechanism to adjust the volume of water flowing through the nozzle, and a plastic dial to adjust the shape of the flow from a fine mist to a single stream.
Another popular household sprinkler nozzle attaches to a garden hose and is then inserted in the ground by means of a spike, with the nozzle itself remaining above-ground. When water flows through the nozzle, it's deflected into a spray that's best for irrigating lawns or gardens. These nozzles can be adjusted to regulate the area covered, from a small arc to a full circle.