With a pressure vacuum breaker, however, a drop in the pressure of the water enables the spring to snap the check valve shut. As soon as the water pressure drops, the check valve closes and backflow does not occur.n a pressure vacuum breaker, the water travels through a check valve and causes a poppet to raise up a guide into an air inlet. The air inlet also has a valve which ordinarily remains closed.
Peter Marshall was born Ralph Pierre LaCock on March 30, 1926, to Ralph and Jean LaCock, a show business family, in Huntington, West Virginia. Following his father's death when Marshall was a teenager, he moved to New York City to be with his mother, a costume designer.
George C. Marshall at VMI. George Catlett Marshall Jr. was born in Uniontown, Pennsylvania, on December 31, 1880, the fourth child of George Catlett Marshall and Laura Bradford Marshall. His father, a businessman, was distantly related to the U.S. Supreme Court chief justice John Marshall.