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.
In 1801, he became chief justice of the U.S. Supreme Court, serving until his death, on July 6, 1835, in Philadelphia, Pennsylvania. Early Life. Chief Justice John Marshall was born on September 24, 1755, in rural Fauquier County, near Germantown on the Virginia frontier. He was the first of 15 children born to Thomas Marshall and Mary Randolph Keith.