A ball check valve is one of several different types of valves designed to permit the flow of material in one direction only. This type of check valve typically utilizes a spring-loaded ball inside a valve body. When pressurized material flows through the valve in one direction, the ball rises to allow passage. If non-pressurized material begins to flow in the opposite direction, the ball lowers to stop the unwanted material. Ball check valves are one of the simplest forms of one-way valves and can be used for many different applications including fuel and water pumping systems.
A typical ball check valve consists of a round ball inside a two piece valve body. The interior walls of the valve body are usually conical to allow for precision seating. A check valve ball may be constructed of either metal or artificial ruby. Some types have a permanent valve body with replaceable inner components. The inner ball may be attached to a conical spring or allowed to move freely inside the valve body.
A spring-type ball check valve is typically employed as a means of controlling the directional flow of high pressure material through a pipeline. When pressurized material passes through the valve in a forward direction, the valve is opened by pushing the ball against the spring. Non-pressurized material flowing in the opposite direction is unable to move the ball and its passage is therefore blocked. Freely moving balls in check valves rely solely on material flow for activation. When low-pressure material flows in a forward direction, the ball is moved upward to allow passage; when material moves backward, the opposite action occurs.
Ball check valves are generally installed in small-capacity water, gas, or fuel supply systems. Although many different types of check valves are available, ball check valves are generally less expensive to purchase and repair. This type of valve is also frequently installed in small diameter piping systems. Check valves are generally used to maintain line pressure in a fuel, water, or gas supply system during pump inactivity. These valves are also utilized to prevent the main supply of material from becoming contaminated by backflowing material.
A specially designed double ball check valve is also manufactured for certain types of applications. This check valve contains two balls in the same valve body to ensure a complete shut-off of backflow. The double-ball design is particularly useful in preventing contaminated material from backflowing into the main supply. A series of two ball check valves is sometimes used to maintain adequate sedentary pressure in long sections of piping.