Mother's Day is a celebration honoring mothers and celebrating motherhood, maternal bonds and the influence of mothers in society. It is celebrated on various days in many parts of the world, yet most commonly in March, April, or May.
Coils, rings, and corrugated ribbon are the common forms of packing used in valves. The form of packing to be used in repacking a particular valve will depend on the valve size, application, and type. Packing materials will be discussed in more detail later in this chapter.
Like valve guides, there are two types of valve seats â integral and insert. Integral seats are part of the casting. Insert seats are pressed into the head and are always used in aluminum cylinder heads. Most pre-1978 integral seats are soft cast iron.