The only operating costs involved in producing the vacuum are for electrical energy and oil for the pumps. Vacuum ... Cryogenic pumps using surfaces refrigerated to liquid hydrogen temperatures (20Ad K.) or below are also employed. The lowanbsp;...
|Title||:||Powder metallurgy equipment manual|
|Author||:||Samuel Bradbury, Powder Metallurgy Equipment Association|
|Publisher||:||Metal Powder Industry - 1986|