A useful mud pump liner inspection record connects the component, the inspection method and the acceptance reference. A note saying “bore checked” leaves the next person unable to tell what was checked or why the liner was accepted. This guide proposes a record format for maintenance planners and parts buyers; it does not prescribe a workshop measurement procedure or a universal wear limit.
Separate the tool result from the service decision
NOV publishes a dedicated MISSION liner bore gauge flyer, document JIG 23-RT-AO-0431, copyright 2023. It describes a size-specific wear-checking tool and its own rejection indication. That indication belongs to the specified tool and application. It should not be transferred to an unrelated gauge or interpreted as a dimensional tolerance for every liner. Read the manufacturer flyer.
The checklist below is an editorial recommendation for documenting an inspection. It is not an additional NOV requirement. Obtain the applicable liner instructions and the gauge instructions before selecting a method. Physical access and inspection should be performed by qualified personnel after the equipment has been isolated and depressurized under the site procedure.
Identify what was actually inspected
Record the pump asset identifier and the liner position within the pump. Include the liner marking, nominal size and drawing or part reference when available. If a marking cannot be read, record it as unreadable and attach a photograph. Do not silently replace missing identification with a number copied from another cylinder.
Keep the nominal size separate from the observed result. The nominal size identifies the intended component; an inspection documents its present condition using a defined method. A nominal-size entry alone does not show that the component meets its service criteria.
For equipment listed in the NOV 14-P-220 product directory, use the actual installed liner records to establish the inspection reference. The directory link helps identify the pump family; it does not certify that a particular gauge or replacement liner is suitable.
Use a repeatable inspection record
- Component: asset identifier, cylinder position, liner marking and nominal size.
- Reference: applicable drawing or manual, revision and the exact acceptance clause.
- Instrument: tool type, identifier, size or range, and calibration or verification status as applicable.
- Method: procedure reference, inspected locations and orientation where the approved method requires them.
- Observation: original reading with units, or the tool-specific pass/fail indication; attach photographs when useful.
- Decision: accepted, rejected or held for review, together with the reviewer and date.
Where a method produces a pass/fail indication, record that indication directly. Do not convert it into an invented diameter. Where it produces numerical readings, retain the original values and units instead of keeping only an average. Note any repeated measurement and the reason for repeating it. The responsible inspector should decide how the results relate to the applicable criteria.
Resolve an incomplete or conflicting result
A blank acceptance-reference field is a documentation gap, not evidence of a pass. Keep the component on hold for technical review until the applicable criterion is available. Similarly, if two records disagree, first compare the component identity, method, tool and measurement locations. Different methods may produce records that cannot be compared directly.
An acceptable bore result should not be expanded into a statement that every feature of the liner is satisfactory. Record visible damage separately and refer it to the responsible inspector. This article does not authorize continued operation, repair machining or reuse based solely on a bore check.
Turn the finding into a clear parts enquiry
When replacement is required, attach the inspection record to the enquiry and state which item is being requested. Distinguish a replacement liner from an inspection gauge. Include the applicable drawing reference and ask the supplier to confirm the proposed item against the installed configuration.
Retain the technical reply with the inspection record. A reply confirming nominal size is narrower than a reply confirming the full component specification. Resolve any remaining difference before treating the proposal as technically accepted. Availability and delivery arrangements belong in the actual enquiry; this guide makes no supply commitment.
Source and scope
The manufacturer source is the NOV MISSION Liner Bore Gauges flyer. The record fields and enquiry workflow are general documentation recommendations. No model-specific wear tolerance, service interval or component interchangeability has been established here.
FAQ
Does a bore gauge result prove that a liner can return to service?
It documents one inspection result. The responsible inspector must apply all relevant component criteria and the equipment procedure before deciding on return to service.
Should a pass/fail gauge result be recorded as a diameter?
No. Record the indication supplied by that method. A numerical diameter requires a measurement method that actually provides it, with the appropriate units and reference.
What if the acceptance limit is missing?
Record the missing reference and hold the decision for technical review. Do not invent a limit from nominal size or copy one from another pump model.