Before designing your SureFire SLR system, it is critical to understand the function of resistance fittings and why they are important to your machinery.
Each resistance fitting is a fixed (non-adjustable component designed for one-way delivery of a precise quantity of oil to a bearing or surface.
Also, the amount of oil delivered to each bearing point is apportioned by the resistance fitting, not the pump. The lubricator controls the volume of oil available for overall system consumption.
Each lubrication point on the machine must have an assigned resistance fitting. The size of the resistance fitting depends upon the calculated oil requirement for that bearing and relative proportioning ratios of the rest of the system.
Bijur refers to the resistance fittings used with automatci cyclic systems as meter units. Each meter unit is shipped with a fixed orifice, a moving pin, and an internal check valve. The valve insures precise discharge without loss of system priming between operating cycles. The orifice and pin size create the metering rate.
The proportioning devices used with continuous systems are called control units. Each control unit proportions a continuous rate of flow and does not contain a check valve. The rate of flow at each point is controlled by the size of the spiral opening in the control unit.
Both types of Bijur resistance fittings (meter and control units) may be mounted in any position without affecting operation.
Selecting the Right Resistance Fitting
All Bijur resistance fittings have been designed to provide the proper amount of resistance to the flow of oil as it passes through it. The amount of resistance determines the amount of lubricant which each point receives. If the proper size fittings are selected, measured amounts of lubricant will provide adequate protection for your machinery.
It is important to specify the proper size resistance fitting for each point in the system since both "over" and "under" lubrication can seriously affect machine operation and life. All Bijur resistance fittings are clearly marked for type of mounting and rate of flow.
Mounting the Resistance Fitting
Both meter units and control units may be installed in any of three basic configurations:
- Straight - Mounted at the bearing
- Tee Junction - Mounted at the bearing
- Junction - Removed from the bearing friction point.
Each type proportioning unit is engineered to deliver a predictable and repeatable flow of oil to a bearing point regardless of its distance from the lubricator or pump.
Flow Rate Versus Flow Valuve
Flow rate is a designation assigned to a resistance fitting and is stamped on the body of the unit. It describes the relative oil flow from the unti. Each numeric increases double flow delivery from the unit. An arrow designating direction of flow is also stamped on every resistance fitting.
Flow value is simply a numeric designation used to refer to the oil permitted to flow through the resistance fitting. The value is relative and does not correlate to either volumetric discharge or amount of discharge on a unit/time basis. Flow value is designated by the Greek letter F (phi).
The provides a convenient method of sizing pumps and resistance fittings in the system.