4.2.3.4 Accessories

Dust separators (SAS or DFT)

If the process produces dust, a dust separator must be installed upstream of the pump since particles result in increased wear and clog up the lubrication circuit. There are various types available to fit the connection flange on the pump.

Condensate separator (KAS or CT)

Condensates can form in the inlet and outlet lines of vacuum systems when pumping down vapors and these can result in corrosion as well as adversely affect the properties of the lubricant. To protect the pump against these condensates, we recommend providing a condensate separator in both the inlet and outlet lines.

Oil mist separator (ONF or OME)

Oil mist separators, also known as oil mist filters, are fitted to the outlet port of rotary vane pumps. They prevent the air from being contaminated by the oil mist that the pump discharges in greater or lesser quantities, depending upon the operating pressure. The separator consists of a cylindrical filter element and a plastic or aluminum housing with an oil collection chamber.

Oil return system (ORF or ODK)

The purpose of oil return systems is to collect and return the atomized pump oil. They are used for all applications involving a high discharge of operating fluid from the rotary vane pump, particularly in high pressure applications or frequent cyclical operation. The use of an oil return system lowers the operating costs and increases process stability, especially where special oils are used in fluorine and nuclear technology. The oil used in the oil mist separator is collected in a volume and returned to the vacuum pump.

Zeolite trap (ZFO or ST)

A zeolite trap uses adsorption to prevent the backflow of hydrocarbons from rotary vane vacuum pumps to vacuum components or vessels on the inlet side. The adsorption agent can be regenerated by baking it out. The regeneration intervals will depend upon the process concerned.

Catalytic trap (URB)

A catalytic trap prevents the backflow of hydrocarbons from single- or two-stage rotary vane vacuum pumps. This is accomplished through catalytic incineration of hydrocarbons at an operating temperature of 250°C to form CO₂ and water vapor. The oxygen that is admitted into the process chamber through periodic venting suffices for self-regeneration. This means that the regeneration intervals are independent of the process in question. Water cooling is required for direct installation of the traps on the inlet ports and/or for use on single-stage rotary vane pumps.

Activated carbon filters (FAK)

Activated carbon filters are used if a wide range of chemicals are present. These include hydrogen sulfide, cyanide, mercury, ammonia, sulfur oxide, nitrous gases, as well as vaporous solvents, acids and alkaline solutions. The activated carbon filters are supplied with a first filling. This filling is replaceable. The service life of the filling is dependent upon the process involved.

Mechanichal and chemical oil filter (OFM, OFC or DE)

The chemical oil filter is interposed in the oil circulation systems of rotary vane pumps. This oil filter strains off dust or particulate matter reaching the operating fluid from the process. In addition, the chemical oil filter adsorbs corrosive substances from the oil. This reduces pump wear and enhances the service life.

Nitrogen cold trap (KLF or LNT)

Nitrogen cold traps are inserted between the vacuum system and the rotary vane pump. They freeze out condensable media from the process gas flow. Rotary vane pumps can be effectively protected from chemical or solvent attack in this way. These traps are available in a standard aluminum version or in a corrosion-resistant stainless steel version. Coolant use and service life depend on the particular application.

When evacuating cryogenic vessels, a cold trap can also protect the vacuum chamber from backflowing operating fluid vapors from the rotary vane pump.

Automatic gas ballast valve (AGB)

The automatic gas ballast valve is the electrical, remote-controlled version of the manual gas ballast. It consists of an electromagnetic valve (closed when currentless) which allows gas to be fed into the high pressure stage of the pump. The automatic gas ballast can be connected to a neutral gas source. The automatic valve should be used if used frequently or if there is restricted access to the pump.

Oil level monitoring (OLS)

An oil level monitoring device is fitted directly to the rotary vane pump between the oil tank and the sightglass. If a large number of pumps need to be monitored or if the pump is installed in an operating environment which is difficult to access, the oil level monitoring system allows the pump to be conveniently monitored.

For selected types of pumps, operations monitoring units are available which monitor either one or more operating parameters of the rotary vane pump. This includes the oil pressure, oil level, the temperature of the operating fluid and the outlet temperature.

Figure 4.4: Accessories for rotary vane pumps

Figure 4.5: Operating principle of a diaphragm vacuum pump