Design Features and Role in Compressor Operation
The valve plate is the most heavily loaded consumable in the valve assembly. In one hour of operation, the FL24 or FL40 plate undergoes tens of thousands of flex cycles. Three parameters are critical simultaneously:
- 47 mm length and 10 mm width — determine the valve port coverage area and opening force. A deviation of even 0.5 mm causes incomplete sealing or sticking
- 0.35 mm thickness — sets the plate’s stiffness and therefore the valve opening pressure. A thicker plate raises opening pressure and reduces output; a thinner one fails quickly from fatigue cracking
- Steel grade — plates are manufactured from special valve strip steel with a high fatigue strength limit; using ordinary spring steel reduces service life by a factor of 3–5
Compatibility: Which Compressors It Fits
| Compressor model | Drive type | Pressure, bar | Plates per head |
|---|---|---|---|
| FL24 | Direct / belt | 8 / 10 | to be confirmed by configuration |
| FL40 | Direct / belt | 8 / 10 | to be confirmed by configuration |
⚠️ Before ordering, confirm the plate count for your specific head configuration with the Acvatron engineer — by compressor serial number or a photo of the valve assembly: +373 22 503-580.
Signs of Valve Plate Wear: When Replacement Is Needed
The plate fails in two ways — gradual fatigue wear or sudden fracture. Both have characteristic symptoms:
- Discharge pressure drop of 15–25% below rated value — the plate no longer seals the port fully
- Increased time to reach pressure — the FL24 or FL40 runs longer than usual before the pressure switch cuts out
- Overheating of the cylinder head — hot compressed air flows back through the damaged plate
- Metallic rattling in the valve assembly — a broken fragment striking the seat or retainer
- Sudden pressure loss during operation — a sign of a fully fractured plate
⚠️ Critical: a fragment of broken valve plate entering the cylinder destroys the piston and liner within minutes. If you hear metallic rattling — stop the compressor immediately and disassemble the head.
Procedure for Replacing Valve Plates on FL24 / FL40
- Preparation — isolate the compressor, bleed the receiver to zero pressure, allow the head to cool.
- Removing the valve cover — unscrew the cover bolts in a cross pattern, evenly. Remove the cover, springs, retainers and old plates. Lay out all parts in order — correct sequence matters during reassembly.
- Inspecting the seat and bore — examine the valve seat surface. If wear exceeds 0.1 mm, lap with 14–28 µm grit paste. Deep scoring is grounds for replacing the valve plate body.
- Fitting new plates — install the 47×10×0.35 mm plates strictly onto the locating pins or orientation marks. No misalignment or offset is permitted — the plate must sit flat along its full length. Do not lubricate the plate’s working surface.
- Reassembly and verification — assemble the head with new gaskets, tighten the cover bolts to the torque specified in the FL documentation. Run unloaded for 20 minutes — monitor head pressure and temperature.
Related Parts for a Complete FL24/FL40 Valve Assembly Service
When replacing the plates, we recommend renewing the entire valve set at the same time:
- Valve plates 47×10×0.35 mm — this item (full set for all valves in the head)
- Valve assembly gasket — seal between the valve plate body and the cylinder head
- Valve springs — after 3,000+ operating hours, springs lose their tension
- Piston rings — if oil consumption or blow-by into the crankcase is observed at the same time
Check availability with Acvatron managers: +373 22 503-580.
Related Parts for Scheduled Remeza LB50/LB75 Maintenance
| Part no. | Description | Interval |
|---|---|---|
| R 21125026 | Large valve plate, 100×19 mm | On condition, every 500–1000 h |
| R 21125014 | Small valve plate (set of 2) | Together with the large plate |
| 21124004 / 21124019 | Complete valve assembly (plate) | On seat wear or total failure |
| R 21145004 | Piston ring set D.80 mm LB50/75 | Every 2000–3000 h |
| R 21177010 | Air filter cartridge D.66×62 mm LB50/75 | Every 300–500 h |
Expert Opinion
“The valve plate is the cheapest consumable in a compressor and at the same time the most critical in terms of failure consequences. On the FL24 and FL40 I recommend replacing the plates preventively every 2,000–3,000 operating hours, without waiting for symptoms. The cost of a set of plates is incomparably lower than the cost of repairing the piston group after a fragment of a broken plate has entered the cylinder. The 0.35 mm thickness is critical: I have seen compressors where 0.4 mm plates were fitted during repair ‘because they were on hand’ — after 400 hours the pressure dropped again, because the valve simply couldn’t open fully at the required pressure.”
Vitali Bolucevschi, Lead Engineer at Acvatron.md
FAQ
❓ Can plates of a different size be used if the correct one is out of stock?
No. A thickness deviation of even 0.05 mm changes the valve opening pressure and the plate’s service life. A length or width deviation causes incomplete port coverage or mechanical sticking. Use only plates with the exact dimensions of 47×10×0.35 mm.
❓ How many valve plates does one FL24 or FL40 compressor need?
This depends on the number of cylinders and the valve assembly configuration. A typical two-cylinder head requires 4 to 8 plates (2–4 per cylinder, for intake and discharge). Confirm the exact quantity from a photo of your head or the serial number with the Acvatron manager.
❓ How should spare valve plates be stored correctly?
In their original packaging or wrapped in oiled paper, laid flat horizontally, free of mechanical load. Plates with a thickness of 0.35 mm deform even under their own weight if stacked vertically. Optimal storage period — no more than 3 years: valve steel loses its spring tension during prolonged storage under temperature and humidity fluctuations.
Reviews
Clear filtersThere are no reviews yet.