A liner change is an opportunity to document the condition of the adjacent wear plate. A work order that says only “liner replaced” leaves the next maintainer without a record of the sealing face that was exposed. This guide offers a focused inspection record for NOV Type P equipment; it does not provide a dismantling procedure or a dimensional acceptance standard.
What the original reference says
NOV booklet 25-101131, pages 8 and 11, calls for examining the wear-plate face when changing a liner, particularly when moving to a smaller bore. It directs replacement for fluid cutting or severe erosion where the new packing will sit. A previously used plate must retain its original seal-facing side if reinstalled; it must not be reversed.
Apply those statements only with the current manual and drawing for the installed assembly. Inspection access must be arranged by authorized personnel after shutdown, energy isolation and verified pressure release under the site's procedure. Do not loosen pressure-containing parts to investigate a suspected leak while the pump is operating.
Define the inspection question
Ask whether the intended packing location has been assessed, rather than simply whether the plate looks clean. Identify the proposed liner and packing from approved equipment documentation. A photograph of a convenient exposed area should not be labelled as evidence for a different contact area.
The following workflow is editorial guidance for recording evidence. It introduces no additional OEM rejection limits, repair methods or interchangeability claims.
Wear-plate record checklist
- Record the asset tag, pump model, serial number and cylinder position.
- Identify the relevant assembly drawing and manual revision.
- Record the removed liner identification and the proposed replacement identification separately.
- Identify the intended packing contact area using the applicable drawing or a qualified maintainer's annotated sketch.
- Describe the observed surface condition and its location; distinguish the observation from a proposed cause.
- Attach a permitted overview photograph and a closer view with a clear location reference.
- Record whether the plate is new or previously used, and how its original orientation was established.
- Name the person responsible for the disposition and link the follow-up work order.
Use “not assessed” for an inaccessible area. Do not turn missing photographs, uncertain orientation or incomplete identification into a default pass. Keep any measurements with their method and governing acceptance document; this article supplies no depth, roughness or flatness tolerance.
Keep component decisions separate
A liner-bore measurement and a wear-plate surface assessment belong to different entries. Link the liner bore inspection record when both are performed, but do not use an acceptable liner reading as approval of the adjacent plate.
The NOV 12-P-160 and NOV 14-P-220 catalogue pages help locate the equipment family. Confirm individual part identification against the installed assembly; a shared family designation does not verify a common plate or packing.
If the evidence is inconclusive, record the unresolved question and refer it to the responsible engineer or OEM service contact. Do not invent a polishing allowance or an alternative seal to close the work order. A parts request should carry the equipment identity and observed condition without claiming a diagnosis that has not been established.
Close with evidence of the disposition
Keep the inspection finding, authorized action and post-work verification as separate fields. Record the procedure used and the responsible person's decision about return to service. This makes it possible to distinguish “replacement requested” from “replacement completed and checked.” Retain unresolved findings with an owner rather than deleting them from the handover.
Source and scope
Primary reference: NOV, How to Treat Your Type P Triplex Mud Pump, 25-101131, ©2025, pages 8 and 11, accessed 23 September 2026. The short OEM summary above concerns inspection at liner changes, surface-condition replacement triggers and used-plate orientation. The documentation checklist and work-order structure are original editorial suggestions. They do not replace model-specific maintenance instructions or establish part compatibility.
FAQ
Does a satisfactory liner-bore measurement approve the wear plate?
No. Record the bore measurement and the plate assessment separately, each against its applicable criteria.
Can an old plate be reversed to present another face?
The cited NOV guidance prohibits reversing a used plate. If its original orientation is uncertain, record that uncertainty and obtain an authorized disposition.
Does this checklist provide a surface-damage tolerance?
No. Use the applicable OEM documentation and responsible engineering assessment. Do not assign a numerical limit from this article.
What belongs in a replacement request?
Include equipment and assembly identification, the intended liner and packing identification, the location of the finding, available evidence and the authorized disposition. Do not infer a kit number from appearance alone.