What is the use of filter optional parts

What is the use of filter optional parts

    On the filter optional parts,the internal automatic drain and external automatic drain is used to filter out the mixture of oil,water and dust filter automatically discharged,reducing human factors affecting system filtration efficiency.Differential pressure gauge,differential pressure meter,electronic differential pressure indicator is used to guide replacement the cartridge time.Liquid level indicator is used to indicate how many internal filter oil,water,dust and pollutants(working condition monitoring internal automatic drain and guidance manually sewage).