An oil field is a region with an abundance of oil wells extracting petroleum (crude oil) from below ground. Pigging has been used for many years to clean larger diameter pipelines in the oil industry. Pigging in the maintenance of pipelines refers to the practice of using pipeline inspection gauges or 'pigs' to perform various operations on a pipeline without stopping the flow of the product in the pipeline. Pigging can be used for almost any section of the transfer process between, for example, blending, storage or filling systems. Pigging systems are already installed in industries handling products as diverse as lubricating oils, paints, chemicals, toiletries, and foodstuffs. Pigs are used in lube oil or painting blending: they are used to clean the pipes to avoid cross-contamination, and to empty the pipes into the product tanks. Usually pigging is done at the beginning and at the end of each batch. Packing hooks are designed to make removal of packing from stuffing box easy. Its flexible design allows access around obstructions and in hard-to-get-at areas. The advantage of these hooks is that it possesses replaceable tips. If the tips break it can be replaced rather than disposing of the entire tool.
A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed fuels such as aerosol gasoline, ethanol, and liquefied petroleum gas by means of an electric spark. Spark plugs have an insulated central electrode which is connected by a heavily insulated wire to an ignition coil or magneto circuit on the outside, forming, with a grounded terminal on the base of the plug, a spark gap inside the cylinder. Spark plugs may be used in furnaces where a combustible mixture should be ignited. Roller chain is the type of chain most commonly used for transmission of mechanical power on bicycles, motorcycles, and in industrial and agricultural machinery. It is a simple, reliable, and efficient means of power transmission. Roller chains are used in low- to mid-speed drives at around 600 to 800 feet per minute; however, at higher speeds, around 2,000 to 3,000 feet per minute, V-belts are normally used due to wear and noise issues. Many automobile engines use roller chains which traditionally drive the camshaft(s) off the crankshaft, generating less noise than a gear drive as used in very high performance engines, and offering more durability than the timing belt frequently used on more modern engines.