US Patent 9121251 Valve for hydraulic fracturing through cement outside casing

A valve for use in fracing through cement casing in a well allows for flow of cement down the well during the cementing process and in the open position allows for fracing fluid to be directed through the cement casing for fracturing the formation adjacent the valve. The valve is constructed so as to reduce the likelihood of the valve to jam as a result of cement or other foreign material.