Selecting a replacement stator for a Moyno® progressive cavity pump requires more than matching the pump family. The pump model, element size, elastomer, fluid chemistry, temperature, abrasion level and operating conditions all affect stator selection. This guide explains the information maintenance and engineering teams should collect before choosing a compatible ACCA replacement stator.
What the Stator Does
The stator is the stationary element of a progressive cavity pump. Its internal geometry works with the helical rotor to form sealed cavities that progress from suction to discharge. Stator condition and elastomer selection directly influence sealing, developed pressure, efficiency and service life.
Signs a Stator May Need Replacement
- Loss of flow at an otherwise unchanged operating speed.
- Reduced ability to develop the required differential pressure.
- Increasing slip or declining volumetric efficiency.
- Visible elastomer wear, swelling, cracking, tearing or chemical attack.
- Performance that improves temporarily when speed is increased but cannot maintain the original duty point.
1. Identify the Pump Family and Model
Start with the complete pump model and any existing stator or element part number. ACCA supports replacement components for multiple Moyno families, including L-Frame, 500 Series, 1000 Series and 2000 Series pumps. For 2000 Series equipment, the Moyno 2000 nameplate and model-code guide can help decode the installed pump.
2. Select the Elastomer for the Fluid
Elastomer selection should be based on the actual process fluid rather than pump model alone. Chemical compatibility, temperature, oils or hydrocarbons, cleaning chemicals and abrasive solids can all change the appropriate compound. NBR, EPDM and fluoroelastomer materials serve different duties and are not interchangeable for every application.
Use the progressive cavity pump stator elastomer guide as an engineering starting point, then confirm the actual fluid composition and temperature before ordering.
3. Account for Abrasion, Solids and Operating Speed
Abrasive solids can accelerate wear at the rotor-stator interface. Pump speed, particle characteristics, solids concentration and the required pressure should therefore be considered together. Lower operating speed is often beneficial in abrasive service when the selected pump displacement can still satisfy the required flow.
For difficult services, review the abrasive-fluid speed guide and maximum particle-size guide.
4. Check Temperature and Chemical Exposure
Temperature affects elastomer properties and can change the interference between rotor and stator. Chemical exposure can cause swelling, hardening, softening or loss of mechanical properties. Provide both normal and maximum process temperature and identify all significant constituents, including cleaning or flush chemicals that may contact the stator.
5. Confirm Pressure and Stage Requirements
The required differential pressure and number of stages influence the load on the pumping element. Do not select a stator solely from flow rate. Confirm discharge pressure, suction conditions and the complete pump element configuration. The pressure-per-stage engineering guide explains how elastomer and abrasion affect practical stage loading.
Information to Provide for Stator Identification
- Complete pump model or nameplate information.
- Existing stator, rotor or element part number when available.
- Fluid name and composition.
- Normal and maximum temperature.
- Solids concentration, particle size and abrasiveness.
- Required flow rate and operating speed.
- Suction and discharge pressure.
- Existing elastomer compound, if known.
If you have only an existing part number, the Moyno cross-reference can help identify the corresponding ACCA replacement reference where a verified match is available.
From Selection to the Correct Model Page
This article is intended to help determine the correct stator specification. Once the pump family and model are known, use the appropriate model or series page in the Moyno pump parts directory for compatible rotors, stators, joint components and maintenance parts.
Moyno® is a trademark of its respective owner. ACCA Pumps is an independent manufacturer and supplier of compatible replacement components and is not affiliated with or endorsed by the original equipment manufacturer.
