Less force is needed to fully close or open the valve, and valves are now less prone to leaking or sticking open. Modern valve design, however, protects both the valve stem seal and valve seat. ![]() Overtightening the valve when opening squeezes this piece, causing damage over time. The damage will cause it to leak, leading the user to overtighten it more. This seal is easily damaged if the valve is overtightened when closed. To compensate for the leak, divers would close the valve even more tightly, which would cause an even greater leak over time. In both cases the valve would start to leak either through the handwheel or out of the valve outlet. The second cause of damage was from closing the valve too tightly, which could affect a different seal located at the end of the handwheel’s inner part, called the valve seal or insert, by pressing it onto the seat. Divers feared that the valve would stick open and delay any ability to shut it off in an emergency. When forced beyond fully open, a seal inside the valve near the handwheel, called the valve stem seal or packing, would become damaged over time from being squeezed against the valve bonnet nut. Overtightening older valves could cause damage in two ways. In the past, valve designs were not as sophisticated as they are today. Have you ever wondered why this procedure was recommended? Is this practice still necessary? This is because of the fact that the habits slowly become a part of their lives.“Turn on your cylinder, and then close it one-quarter turn.” Many divers have heard this instruction during and after their scuba certification classes. It is often seen within the elderly that they are not open to making even small changes. The phrase is a literal meaning one and emphasizes on the fact that a habit becomes more and more ingrained into a person with time, whether good or bad. The first known citation in the United States is in an article by Benjamin Franklin printed in the London Chronicle in December 1758. But it is high time other take a chance to help granny out instead of it always just being my mom.Ī teacher – Gregory Y Titelman explains in his book America’s Popular Proverbs and Sayings that this phrase can be traced back to history before 1450. My grandmother expects my mother to press her feet every day, old habits die hard.She is stubborn about not taking any painkillers even though she has been through a major surgery. ![]() I have been going for a walk in the mornings for the last 10 years now and old habits die hard. ![]()
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