Notes on Installation
Cleanliness is a priority when installing mechanical seals. Dirt particles on the seal faces or O-Rings can cause instant leakage and even damage the seal faces.
All DEPAC seal shipments contain installation and operating instructions with corresponding drawings for the seal. Operating instructions should obviously be read and appropriate measures taken before installing a seal.
Above all it is important to check that the installation dimensions match the related seal dimensions.

Sleeve Edges
All edges or shoulders on sleeves and shafts, over which a seal must be pushed during installation, have to be clean of burrs and should be chamfered to no less than 25 to 30 ° x 3 mm (0.12"). O-Rings or other elastomers, which for installation reasons need to slide over such edges or shoulders, are very sensitive and must be protected accordingly from damage during installation.

Face Protection
Single seals which are delivered with a special wax protective coating on their faces must be cleaned so that no trace of this wax remains. The special wax leaves a slightly oily film on the face, which is useful when starting the seal. However, no dust or dirt particles must be allowed to stick to this oily film during installation. This can cause leakage or damage to the faces.

Set Screws
An anti-loosening agent (e.g. Loctite 241) should be applied to the set screws, which tighten the seal to the shaft or sleeve, and to the connecting bolts, which tighten the seal gland to the equipment housing.
To prevent the mechanical seal from slipping on the shaft or sleeve at operating pressures of 15 bar or higher, it is recommended to drill the shaft or sleeve where the set screws are to be tightened.

Secondary Seals
Silicon grease or silicon oil should be applied to secondary seals (0-Rings, wedges, etc.) for easier installation.  Conventional mineral oil products should be avoided because some elastomers are not resistant to such oils.  Important: No oil or grease of any kind is allowed to be used on elastomer bellows seals. Only soapy water is permitted as an installation aid on such seals.

Welded Bellows / Rolled Bellows
Please note that welded and rolled bellows seals must not be overcompressed during installation. This could cause a pressure set which would reduce the calculated spring rate and causes the seal to fail. These seals have to be assembled with a mounting tool, which bridges the bellows and applies the thrust directly to the parts to be installed. These mounting tools are either delivered with the seal or should be prepared accordingly.

Double Mechanical Seals
The barrier chamber on double mechanical seals must be carefully vented.  Seals in DEPAC series 321,326 and 365 have special venting devices incorporated as standard, which should be used accordingly when filling the seal chamber. Dry running of mechanical seals must be avoided at all cost.
With double mechanical seals, particularly in applications on agitators to seal off gases or non-lubricating media, the barrier fluid pressure should be higher than the pressure of the gas or medium in order to guarantee lubrication of the inner pair of faces.

Springs
If mechanical seals with single springs (conical springs) are used, the direction of the spring winding has to correspond with the direction of the shaft rotation. For this reason it is important when selecting seals to check if they are dependent on the direction of rotation or independent of it. The drawings on the right indicate the necessary spring winding direction in relation to the direction of the shaft rotation.

A set of springs (individual springs equally spaced around the circumference) should be selected if possible. Sine springs (and "super sine" springs) have a steeper spring rate (characteristic curve). Even little wear leads accordingly to a large loss of contact pressure. Seal life is artificially shortened by springs of this type.

Shaft-Sleeve OD Tolerances
The surface precision of the shafts or sleeves on which mechanical seals are installed should comply with DIN h6 tolerances.