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.
Thurgood Marshall was the first African-American Supreme Court Justice in the United States, and was one of the 20 th century's most influential Civil Rights advocates, having been responsible for ending segregation in schools. Thurgood Marshall was born on July 2 nd , 1908, in Baltimore, Maryland, to Norma Marshall, a kindergarten teacher, and William Marshall, a railroad porter. Thurgood was a good student and graduated from high school a year early, going on to attend Lincoln University where he graduated with honors majoring in American literature and philosophy.