How to Select a Progressive Divider Block: Outlets, Metering Volume and Monitoring

The selection of a progressive divider block cannot be determined by outlet quantity alone. A technically appropriate configuration must also account for the lubricant demand of each point, the required metering volume, the number of discharges per lubrication event, the circuit arrangement and the required monitoring function.

In practice, two machines may contain the same number of lubrication points while requiring entirely different divider configurations. One machine may contain bearings with uniform lubricant demand, whereas another may include small bearings, loaded pins and large pivots that require several different delivery volumes.

A systematic progressive divider valve selection should therefore follow a defined engineering sequence:

Lubrication-point demand → Metering volume → Active outlet arrangement → Divider series → Monitoring method → Final configuration

Applying this sequence reduces the risk of selecting a divider with the correct number of physical ports but an unsuitable delivery pattern.

Establish the Lubrication-Point Schedule Before Model Selection

The first stage of divider selection is the preparation of a point-by-point lubrication schedule. This schedule defines the required delivery pattern and provides the basis for selecting the metering sections.

The required lubricant quantity should be based on the machine manufacturer's specification, a bearing or pin calculation, or a maintenance schedule validated under actual operating conditions. Divider displacement should be selected to reproduce an established lubrication requirement rather than to determine the requirement itself.

The point schedule should be supplemented by the following engineering information:

• Lubricant type, consistency grade and base-oil viscosity.
• Minimum startup temperature and normal operating-temperature range.
• Main-line and secondary-line lengths.
• Tube dimensions, hose sections and connection standards.
• Available mounting envelope and maintenance clearance.
• Criticality of individual lubrication points.
• Required visual indication or electrical feedback.

Engineering consideration: Lubrication points with substantially different operating intervals should be evaluated as separate zones. Attempting to compensate for a major interval difference only through metering-section displacement may result in an unnecessarily complex divider configuration.

Distinguish Outlet Quantity From Lubrication-Point Quantity

The number of physical outlet positions does not necessarily correspond to the number of independently supplied lubrication points.

In an integrated divider, each active outlet normally supplies one final lubrication line. In a modular divider, however, a metering section may provide two individual outlets or one combined outlet. In addition, an outlet from a primary divider may supply an entire secondary divider rather than a single bearing.

Three quantities should therefore be identified separately:

• Metering sections: The piston sections installed between the divider inlet and end blocks.
• Physical outlet positions: The available outlet locations on both sides of the metering sections.
• Active delivery lines: The lines connected to final lubrication points or secondary dividers.

A modular divider containing six metering sections may have twelve physical outlet positions. When two of these sections are configured as single-outlet sections, the completed assembly provides ten active delivery lines.

An unused outlet should not be closed by installing an arbitrary plug. A single-outlet configuration must use the approved metering section or the specified internal combining arrangement. Incorrect outlet closure may interrupt the progressive piston sequence or alter the intended delivery volume.

Determine the Required Metering Volume per Discharge

Machine lubrication requirements are generally specified as a volume per lubrication event, whereas divider performance is commonly stated as a volume per stroke or rated discharge at each outlet.

The required divider output may be calculated as follows:

Required output per discharge = Required point volume per event ÷ Number of rated discharges per event q_i = Q_i ÷ n

In this expression:

• Q_i represents the lubricant quantity required by point i during one lubrication event.
• n represents the number of rated divider discharges scheduled during the event.
• q_i represents the required output from the corresponding outlet during each discharge.

For a lubrication point requiring 0.24 cm³ during each lubrication event, the required divider output would be:

• 0.24 cm³ when one rated discharge is completed per event;
• 0.12 cm³ when two rated discharges are completed per event;
• 0.06 cm³ when four rated discharges are completed per event.

Adjusting the number of discharges may allow the required point volume to be matched with a standard metering section. This adjustment also changes pump operating duration and monitoring-signal counts. It must therefore be assessed as part of the complete lubrication-system design.

Control-system consideration: The definitions of divider stroke, detector signal and controller cycle should be confirmed before the PLC or lubrication controller is programmed. The divider should be sized according to its rated displacement, while the relationship between piston movement and electrical pulse output should be verified during commissioning.

PFM Metering Sections: T and S Configurations

The PFM series provides eight metering configurations for applications requiring different lubricant quantities at individual points.

The suffix T identifies a twin-outlet metering section. Each side supplies the stated output independently. The suffix S identifies a single-outlet section in which the section output is combined into one delivery line. The resulting delivery is twice the per-outlet value of the corresponding T section.

A PFM divider may contain between three and ten metering sections. The selected configuration must specify the number of sections, the number of active outlets and the sequence of the individual metering sections.

Consequently, an enquiry specifying only a ten-outlet divider does not provide sufficient information for final selection. A ten-outlet assembly supplying equal quantities requires a different section arrangement from a ten-outlet assembly supplying several volume groups.

Progressive-Divider Selection Example

The following example illustrates the preliminary selection of a PFM divider for ten lubrication points with four different delivery requirements. The calculation assumes one rated discharge from every active outlet during each lubrication event.

This arrangement contains eight metering sections and provides ten active delivery lines. A preliminary configuration description may be written as:

PFM-8/10-12T/12T/12S/12S/20S/20S/24S/24S-E

The theoretical total delivery during the assumed lubrication event is:

(4 × 0.12) + (2 × 0.24) + (2 × 0.40) + (2 × 0.48) Total theoretical delivery = 2.72 cm³

The calculated total provides a basis for reviewing pump capacity and expected operating time. The final system setting must also consider effective pump output under pressure, lubricant temperature, pressure loss, line expansion and the signal-counting method used by the controller.

The preliminary configuration is not a final production order code. Metering-section sequence, detector position, outlet orientation, thread specifications, tube dimensions and installation clearance must be confirmed on the approved technical drawing.

Comparison of PFB, PFMS, PFM and PFG Progressive Dividers

PFB is an integrated divider with a fixed output at each active outlet. PFMS, PFM and PFG use modular metering sections and are therefore better suited to applications requiring different lubricant quantities at individual points.

PFMS has a more compact body than PFM, while PFG uses a larger construction and provides a broader range of displacement configurations. The metering sections used by the three modular series are not interchangeable, and section designations should always be verified against the corresponding product data.

PFB for Uniform Delivery Requirements

PFB is generally appropriate when all lubrication points require the same delivery or a common multiple of the fixed 0.20 cm³ output.

For example, twelve points requiring 0.40 cm³ per lubrication event may be supplied by a twelve-outlet PFB completing two rated discharges per event, subject to confirmation of pump output, operating pressure and cycle duration.

The integrated construction simplifies the outlet arrangement. However, the specified outlet fittings, tube dimensions and connection details must be included in the order review.

PFMS for Space-Constrained Installations

PFMS is suitable for compact machinery, enclosed installations and lubrication panels with limited mounting length, provided that the available metering configurations correspond to the required delivery pattern.

Overall body length should not be the only selection criterion. Sufficient clearance must remain available for outlet fittings, tube bending, detector installation and future maintenance.

PFM for Mixed Point Demands

PFM provides a practical balance between physical size and metering flexibility. It is suitable for machines containing several groups of lubrication points with different lubricant requirements within the published PFM displacement range.

The defined T and S section options also allow the final outlet arrangement to be documented clearly and matched against a numbered machine lubrication drawing.

PFG for a Wider Displacement Range

PFG should be evaluated when the required difference between small-bearing demand and high-load pin or pivot demand cannot be accommodated efficiently by the smaller modular series.

Its broader range of metering configurations provides greater flexibility for unequal delivery requirements. The larger body dimensions must nevertheless be reviewed against the available mounting envelope and maintenance access.

Define the Required Monitoring Function

Divider monitoring should be selected according to equipment criticality, operating conditions and the information required by the maintenance system or machine controller.

PFM configuration requirement: The M visual indicator must be considered during selection of the metering stack. It is available only when the assembly includes a compatible 20T, 20S, 24T or 24S metering section.

Monitoring Capability and Technical Limitations

A piston detector confirms movement of the monitored divider piston. Because the individual pistons operate in sequence, a blocked outlet or stalled metering section will normally prevent completion of the progressive cycle.

This principle allows one monitoring device to provide effective confirmation of divider operation without installing a separate detector at every outlet.

The detector signal does not, however, provide direct confirmation that lubricant has entered every bearing. A disconnected, damaged or incorrectly routed secondary line may continue to provide an open discharge path and may not cause the divider to stop.

Critical applications should therefore combine divider-cycle monitoring with appropriate installation and maintenance measures:

• Permanent identification at both ends of each lubrication line.
• Mechanical protection for tubing exposed to impact or abrasion.
• Verification of lubricant discharge at every point during commissioning.
• Zone-level monitoring where rapid fault location is required.
• Point-level monitoring where the consequence of lubrication failure justifies it.

In a primary-secondary circuit, a detector installed on the primary divider may indicate that the system has stopped without identifying the affected secondary branch. Separate monitoring of important zones can reduce troubleshooting time and improve maintenance response.

Alarm Timeout Under Actual Operating Conditions

Divider cycle duration is influenced by lubricant consistency, temperature, line resistance, point backpressure and effective pump output.

A divider tested with warm grease under workshop conditions may operate considerably more slowly during a cold machine start. The alarm timeout should therefore be established according to the most demanding credible operating condition.

The timeout review should include:

• The specified lubricant at the minimum startup temperature.
• The longest and smallest-bore line in the circuit.
• The highest expected resistance at a lubrication point.
• Effective pump output at operating pressure.
• The required number of divider discharges per lubrication event.

An excessively short timeout may cause nuisance alarms. An excessively long timeout may delay the detection of an actual blockage.

Final Engineering Checks Before Part-Number Approval

The divider configuration should not be released for purchase until the following items have been reviewed:

• Lubricant type, consistency grade and minimum startup temperature.
• Main-line and secondary-line lengths.
• Tube dimensions, flexible-hose sections and fitting restrictions.
• Expected operating pressure and pressure-relief setting.
• Inlet thread, outlet fittings and tube outside diameter.
• Available mounting length and maintenance clearance.
• Detector voltage, output type, connector and cable length.
• Primary-divider, secondary-divider or direct-to-point function.
• Numbered outlet drawing corresponding to the machine lubrication points.

Maximum divider pressure represents a component operating limit rather than a preferred system pressure. A higher pressure rating does not compensate for unsuitable lubricant, excessive pipeline resistance, undersized tubing or an incorrect controller timeout.

Technical Information Required for an Accurate RFQ

A complete technical enquiry should include sufficient information to determine the divider series, metering sections, outlet configuration and monitoring method.

1. Total number of independently supplied lubrication points.
2. Required lubricant quantity at each point per event.
3. Lubrication interval or machine-cycle basis.
4. Lubricant specification and operating-temperature range.
5. Approximate main-line and secondary-line lengths.
6. Tube dimensions and connection standards.
7. Available divider mounting envelope.
8. Primary- or secondary-divider position in the system.
9. Required monitoring function and PLC input specification.
10. Planned spare outlets or future machine variants.

Outlet quantity alone permits only a preliminary estimate of divider body size. Final metering-section selection requires point-by-point lubricant quantities and the relevant operating conditions.

Frequently Asked Questions

How Is the Required Number of Progressive-Divider Outlets Determined?

The calculation should begin with the number of independently supplied final lubrication points. Single-outlet metering sections and primary-divider outlets supplying secondary dividers must then be considered. The number of active delivery lines may therefore differ from the number of physical outlet positions.

May an Unused Progressive-Divider Outlet Be Plugged?

An unused outlet should not be closed without reference to the approved divider configuration. A designated single-outlet section, internal combining arrangement or authorized closure method must be used. Incorrect closure may interrupt the progressive sequence or alter the specified delivery volume.

When Is PFB More Appropriate Than PFM?

PFB is appropriate when all lubrication points can accept the same 0.20 cm³-per-stroke delivery or a common multiple of that value. PFM is more appropriate when the point schedule requires several different delivery volumes that can be matched by its T and S metering sections.

Does One Piston Detector Confirm Operation of the Entire Divider?

A piston detector confirms completion of the monitored progressive sequence. It does not inspect every secondary line and does not directly verify that lubricant has entered each individual bearing.

Can Lubrication Points With Different Intervals Use the Same Divider?

Points with different intervals may share one divider only when their required lubricant quantities can be represented by a practical displacement ratio using the same operating schedule. Substantial interval differences are generally better managed through separate circuits or independently controlled zones.