Agilent Varian VHS-4 Air Cooled Diffusion Pump Heater Clamp PN 88164301 This is a replacement heater clamp for the Agilent Varian VHS-4 Air Cooled Diffusion Pump. 1 required per pump.

Agilent Varian VHS-4 Ceramic Insulator for Cold Cap, Diffusion Pump Replacement Part Agilent Varian Part Number 699006025 These Agilent Varian VHS-4 ceramic insulators are OEM Agilent Varian replacement parts for the VHS-4 diffusion vacuum pumps, having Agilent Varian part number 699006025. These ceramic insulators are used as a spacer between the jet assembly and the cold cap (please see the center photograph above and item #20 in the illustration below).

Agilent Varian VHS-4 Extended Cold Cap, Mexican Hat, Diffusion Vacuum Pump Replacement Parts Agilent Varian Part Number F6898301 These Agilent Varian VHS-4 extended cold caps are OEM Agilent Varian replacement parts for the VHS-4 diffusion vacuum pumps. The extended cold cap is sometimes referred to as a Mexican Hat due to its shape. There are two types of cold caps, standard and extended. The type of cold cap used will influence factors, such as, oil backstreaming and final pumping speed of the diffusion pump. For example, the Extended Cold Cap is an option that fits inside the VHS-4, VHS-6, and VHS-10 pumps in place of the standard cold cap. It stops backstreaming as effectively as an optically dense baffle, yet it retains 80% of the pump’s speed. Residual backstreaming is so low that it cannot be measured by the American Vacuum Society’s standard collection method. For removal installation procedures of cold cap see page 37 of instruction manual PDF below. These extended cold caps are OEM original Agilent Varian replacement parts with part number F6898301, see item #16 on (diagram exploded view & parts illustration) below.

Varian VHS-4, VHS-6 and VHS-250 Old-Style Diffusion Vacuum Pump Bottom Heater Cover These Varian Varian VHS-4, VHS-6 and VHS-250 diffusion vacuum pump replacement bottom heater covers are made of Aluminum and are direct replacements. The heater cover protects the bottom of the diffusion pump and the heater assemble. Other diffusion pump accessories are available on this web site.

Varian VHS-4 Old-Style Diffusion Pump Thermal Overload Switch Aluminum Cover Box These Varian VHS-4 diffusion vacuum pump replacement thermal overload switch covers are made of aluminum. They also include the replacement mounting hardware. The thermal switch is used to protect the diffusion pump from over heating which typically occurs from lack of cooling water.

Agilent Varian VHS-6 & VHS-4 Diffusion Pump Replacement Standard Cold Cap.Agilent Varian PN 86488301 These Agilent Varian VHS-6 and VHS-4 diffusion pump standard cold caps are a replacement part that can be installed at the customer’s location. There are two types of cold caps, standard and extended. The type of cold cap used will influence factors, such as, oil backstreaming and final pumping speed of the diffusion pump. For example, the Extended Cold Cap is an option that fits inside the VHS-4, VHS-6, and VHS-10 pumps in place of the standard cold cap. It stops backstreaming as effectively as an optically dense baffle, yet it retains 80% of the pump’s speed. Residual backstreaming is so low that it cannot be measured by the American Vacuum Society’s standard collection method. For location of the cold cap please see item #1 on diagram exploded view & parts illustration shown below. For removal installation procedures of cold cap see page 37 of instruction manual PDF below. These standard cold caps are OEM original Agilent Varian replacement parts with part number 86488301.