Eccentric screw pump<\/strong><\/td>Descriptive term emphasizing the rotor’s eccentric motion<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nAll four terms refer to exactly the same pump configuration: one rotor, one stator, eccentric motion, progressive cavities. Understanding this equivalence is the first step in resolving the “PC pump vs screw pump” confusion.<\/p>\n\n\n\n
3. Are Progressive Cavity Pumps and Screw Pumps the Same Thing?<\/h2>\n\n\n\n This is the question at the heart of the search query: is a progressive cavity pump the same thing as a screw pump? The answer requires both a short version and an explanation.<\/p>\n\n\n\n
Short answer:<\/strong> A progressive cavity pump is<\/strong> a screw pump \u2014 specifically, a single-screw pump. It is one type within the broader screw pump family. The relationship is one of category and member<\/strong>: all progressive cavity pumps are screw pumps, but not all screw pumps are progressive cavity pumps.<\/p>\n\n\n\nTable: Progressive Cavity Pump vs Screw Pump \u2014 Relationship Clarification<\/strong><\/p>\n\n\n\nQuestion<\/th> Answer<\/th><\/tr><\/thead> Is a PC pump a screw pump?<\/td> Yes<\/strong> \u2014 it is a single-screw pump<\/td><\/tr>Are all screw pumps PC pumps?<\/td> No<\/strong> \u2014 twin-screw and triple-screw pumps are also screw pumps<\/td><\/tr>Can I use the terms interchangeably?<\/td> Sometimes<\/strong> \u2014 only when the context clearly refers to a single-screw configuration<\/td><\/tr>Which term is “correct” in a specification?<\/td> Both can be correct<\/strong> \u2014 but “progressive cavity pump” or “single-screw pump” is unambiguous<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nWhy the Confusion Exists: A Brief History<\/h3>\n\n\n\n The terminology confusion has roots in the parallel development of screw pump technology on different continents:<\/p>\n\n\n\n
\nNorth America (1930s):<\/strong> Ren\u00e9 Moineau invented the progressive cavity pump design. The term “progressive cavity pump” became the standard terminology in North American water, wastewater, and industrial markets, later popularized through the Moyno brand.<\/li>\n\n\n\nEurope (parallel development):<\/strong> European manufacturers, particularly in Germany and Scandinavia, developed multi-screw pump configurations (twin and triple-screw) for oil, marine, and hydraulic applications. In these markets, “screw pump” became the umbrella term for all rotary screw-type positive displacement pumps.<\/li>\n\n\n\nGlobalization effect:<\/strong> As international engineering firms, EPC contractors, and global equipment suppliers cross-pollinated markets, both terms entered common use \u2014 often without the clarifying context of which specific screw configuration was intended.<\/li>\n<\/ul>\n\n\n\nWhat “Screw Pump” Can Mean: Four Possibilities<\/h3>\n\n\n\n When someone says “screw pump” without qualification, they could be referring to any of the following:<\/p>\n\n\n\n
Table: The Meanings of “Screw Pump” \u2014 Possible Pump Types<\/strong><\/p>\n\n\n\nPump Type<\/th> Also Known As<\/th> Key Identifier<\/th> Common Industries<\/th><\/tr><\/thead> Single-screw pump<\/strong><\/td>Progressive cavity pump, PC pump, mono-pump<\/td> Elastomer stator, eccentric rotor<\/td> Water\/wastewater, sludge, oil & gas, chemical, food<\/td><\/tr> Twin-screw pump<\/strong><\/td>Two-screw pump, timed screw pump<\/td> Non-contacting metal screws, external timing gears<\/td> Oil transfer, tank stripping, multiphase, marine<\/td><\/tr> Triple-screw pump<\/strong><\/td>Three-screw pump<\/td> One drive + two idler screws, clean fluids only<\/td> Lubrication, hydraulics, fuel injection<\/td><\/tr> Archimedes screw pump<\/strong><\/td>Screw pump (archaic\/open-channel context)<\/td> Large-diameter inclined screw, open channel flow<\/td> Wastewater lift stations, irrigation, low-head drainage<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nNote: Archimedes screw pumps are a completely different pump category \u2014 a low-head, high-volume open-channel conveying device unrelated to the positive displacement screw pumps used in process industries. They are included here only because they occasionally create terminology confusion in wastewater and civil engineering contexts.<\/em><\/p>\n\n\n\nIn water, wastewater, and general industrial applications, “screw pump” most commonly defaults to a single-screw\/progressive cavity pump. In oil and gas, marine fuel handling, and hydraulic applications, “screw pump” more often refers to twin or triple-screw configurations. Always verify the intended meaning against the application context.<\/p>\n\n\n\n
4. What Are the Different Types of Screw Pumps?<\/h2>\n\n\n\nUnderstanding where the progressive cavity pump fits within the screw pump family requires a clear view of all family members. The table below provides a concise comparison of the three main screw pump configurations.<\/p>\n\n\n\n
Table: Screw Pump Family \u2014 Type Comparison<\/strong><\/p>\n\n\n\nFeature<\/th> Single-Screw (PC Pump)<\/th> Twin-Screw<\/th> Triple-Screw<\/th><\/tr><\/thead> Number of screws<\/strong><\/td>1 rotor + 1 stator<\/td> 2 parallel screws<\/td> 1 drive + 2 idler screws<\/td><\/tr> Contact between screws?<\/strong><\/td>Yes \u2014 rotor contacts stator<\/td> No \u2014 screws are non-contacting<\/td> Yes \u2014 drive screw contacts idlers<\/td><\/tr> Sealing mechanism<\/strong><\/td>Rotor-stator interference fit<\/td> Precision clearance between screws and housing<\/td> Precision clearance between screws<\/td><\/tr> Pressure capability<\/strong><\/td>6\u201312 bar (up to 120 m head)<\/td> Up to 40+ bar<\/td> Up to 200+ bar<\/td><\/tr> Viscosity range<\/strong><\/td>20\u20131,000,000+ cSt<\/td> 1\u2013100,000 cSt<\/td> 1\u20135,000 cSt<\/td><\/tr> Solids handling<\/strong><\/td>Excellent<\/td> Poor \u2014 requires clean fluid<\/td> None \u2014 clean lubricating fluids only<\/td><\/tr> Gas handling<\/strong><\/td>Moderate (up to ~20%)<\/td> Excellent (up to 100% slugs)<\/td> Poor<\/td><\/tr> Shear<\/strong><\/td>Very low<\/td> Low to moderate<\/td> Moderate<\/td><\/tr> Stator?<\/strong><\/td>Yes \u2014 elastomer, consumable<\/td> No \u2014 all metal<\/td> No \u2014 all metal<\/td><\/tr> Common applications<\/strong><\/td>Sludge, slurries, crude oil, food, chemicals<\/td> Fuel transfer, tank stripping, multiphase<\/td> Lubricating oil, hydraulics, fuel injection<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nThe PC Pump’s Position in the Family<\/h3>\n\n\n\n The progressive cavity pump is the only screw pump configuration that uses an elastomer stator. This design choice defines its entire application profile: it sacrifices pressure capability and dry-run tolerance (relative to all-metal twin and triple-screw designs) in exchange for unparalleled solids handling and ultra-high-viscosity capability. It is the screw pump for difficult fluids<\/strong> \u2014 fluids that are too thick, too abrasive, too fibrous, or too shear-sensitive for any other rotary pump type. Unlike centrifugal pumps, which rely on kinetic energy and lose efficiency at high viscosity, progressive cavity pumps are positive displacement devices that maintain stable volumetric efficiency across their entire viscosity range.<\/p>\n\n\n\n5. How Does API 676 Define Progressive Cavity Pumps and Screw Pumps?<\/h2>\n\n\n\n When terminology is ambiguous in everyday use, industry standards provide the authoritative reference. For screw pumps in industrial service, the primary governing standard is API 676 \u2014 “Rotary Positive Displacement Pumps.” Single-screw and progressive cavity pumps are additionally covered by ANSI\/HI 3.1-3.5 standards, which provide application-specific guidance for progressive cavity pump selection and testing.<\/p>\n\n\n\n
API 676 and ANSI\/HI Classification<\/h3>\n\n\n\n API 676 classifies rotary positive displacement pumps into distinct categories. Under this standard, screw pumps are one of the recognized rotary PD pump types, and they are subdivided by screw configuration:<\/p>\n\n\n\n
\nSingle-screw pump<\/strong> = Progressive cavity pump (API 676 primarily covers twin and triple-screw pumps for petroleum service; single-screw\/PC pumps are comprehensively addressed by ANSI\/HI 3.1-3.5)<\/li>\n\n\n\nTwin-screw pump<\/strong> \u2014 covered in detail by API 676 for petroleum applications<\/li>\n\n\n\nTriple-screw pump<\/strong> \u2014 covered in detail by API 676 for clean fluid, high-pressure service<\/li>\n<\/ul>\n\n\n\nWhat This Means for Your Procurement<\/h3>\n\n\n\n Engineers at Changyu Pump, based on over 20 years of experience navigating international pump specifications, offer this guideline: when writing or responding to a technical specification, use “single-screw pump” or “progressive cavity pump” for maximum clarity. If the specification uses “screw pump” without qualification, always request written clarification on whether the intended configuration is single, twin, or triple-screw. If the supplier cannot provide a clear answer on screw configuration, proceed with a technical evaluation of the fluid characteristics rather than relying on the supplier’s terminology \u2014 this is itself a warning sign. A five-minute clarification during bidding prevents a five-figure correction during commissioning.<\/strong><\/p>\n\n\n\nOther Relevant Standards<\/h3>\n\n\n\nStandard<\/th> Relevance<\/th><\/tr><\/thead> API 676<\/strong><\/td>Primary standard for twin and triple-screw pumps in petroleum and natural gas service<\/td><\/tr> ANSI\/HI 3.1-3.5<\/strong><\/td>Comprehensive standard for progressive cavity\/single-screw pump selection, testing, and application<\/td><\/tr> ISO 9001<\/strong><\/td>Quality management \u2014 baseline manufacturing certification<\/td><\/tr> ASTM D471<\/strong><\/td>Elastomer compatibility testing \u2014 critical for stator material selection<\/td><\/tr> ISO 15136<\/strong><\/td>Downhole PC pumps for artificial lift \u2014 uses “PCP” (progressive cavity pump) terminology<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n6. What Are the Key Technical Differences Between PC Pumps and Other Screw Pumps?<\/h2>\n\n\n\nWhile a PC pump is<\/strong> a screw pump, the performance characteristics of a single-screw\/PC pump differ substantially from twin-screw and triple-screw alternatives. These differences explain why the distinction matters \u2014 even though the terms overlap.<\/p>\n\n\n\nPerformance Profile: PC Pump vs Twin-Screw Pump<\/h3>\n\n\n\n Since twin-screw pumps are the second most common screw pump configuration (and the one most often confused with PC pumps in procurement errors), the direct comparison is instructive.<\/p>\n\n\n\n
Table: PC Pump (Single-Screw) vs Twin-Screw \u2014 Key Technical Differences<\/strong><\/p>\n\n\n\nParameter<\/th> PC Pump (Single-Screw)<\/th> Twin-Screw Pump<\/th> Why It Matters<\/th><\/tr><\/thead> Solids<\/strong><\/td>Handles particles (size depends on pump geometry); abrasive slurries<\/td> Requires clean fluid; particles damage clearances<\/td> If your fluid contains grit, sand, or catalyst \u2014 PC pump only<\/td><\/tr> Gas<\/strong><\/td>Up to ~20% gas fraction<\/td> Up to 100% transient gas slugs<\/td> Tank stripping and multiphase \u2192 twin-screw<\/td><\/tr> Pressure<\/strong><\/td>6\u201312 bar<\/td> Up to 40+ bar<\/td> High-pressure injection \u2192 twin-screw<\/td><\/tr> Viscosity ceiling<\/strong><\/td>> 1,000,000 cSt<\/td> ~100,000 cSt<\/td> Polymer melts, heavy crude \u2192 PC pump<\/td><\/tr> Shear<\/strong><\/td>Very low<\/td> Low to moderate<\/td> Polymers, emulsions \u2192 PC pump<\/td><\/tr> Maintenance<\/strong><\/td>Stator replacement (predictable)<\/td> Gear and bearing maintenance<\/td> PC pump maintenance is simpler<\/td><\/tr> Dry-run tolerance<\/strong><\/td>None<\/td> Limited (minutes)<\/td> Intermittent dry-run risk \u2192 twin-screw<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nThe fundamental design trade-off: PC pumps use an elastomer stator that handles solids at the cost of pressure and dry-run tolerance. Twin-screw pumps use all-metal non-contacting screws that handle gas and pressure at the cost of solids intolerance. This is why clarifying which “screw pump” is being specified is not a semantic exercise \u2014 it determines whether the pump survives the application.<\/p>\n\n\n\n
7. When Should You Use “Progressive Cavity Pump” vs “Screw Pump”?<\/h2>\n\n\n\n Beyond the technical relationship, there is a practical question: in real-world engineering and procurement situations, which term should you use \u2014 and how should you interpret the term when others use it?<\/p>\n\n\n\n
Formal vs Informal Settings<\/h3>\n\n\n\nSetting<\/th> Recommended Term<\/th> Rationale<\/th><\/tr><\/thead> Technical specification \/ datasheet<\/strong><\/td>“Progressive cavity pump” or “Single-screw pump”<\/td> Unambiguous; leaves no room for misinterpretation<\/td><\/tr> RFQ \/ inquiry<\/strong><\/td>“Progressive cavity pump (single-screw type)”<\/td> Clarifies the exact configuration in commercial documents<\/td><\/tr> Contract \/ purchase order<\/strong><\/td>Match the specification exactly<\/td> Do not substitute terms in binding documents<\/td><\/tr> Email \/ informal discussion<\/strong><\/td>Either term is acceptable if context is clear<\/td> “Screw pump for sludge” clearly means PC pump<\/td><\/tr> Supplier meeting<\/strong><\/td>Clarify at the outset: “By screw pump, we mean single-screw\/progressive cavity”<\/td> Prevents the most common procurement error<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nIndustry Preferences<\/h3>\n\n\n\n Different industries have developed different default terminologies over decades of practice:<\/p>\n\n\n\nIndustry<\/th> Default Term<\/th> Notes<\/th><\/tr><\/thead> Water & wastewater<\/strong><\/td>Progressive cavity pump \/ PC pump<\/td> North American standard; “screw pump” may be confused with Archimedes screw<\/td><\/tr> Oil & gas (upstream)<\/strong><\/td>Screw pump \/ PCP (progressive cavity pump)<\/td> “PCP” is common for downhole applications per ISO 15136<\/td><\/tr> Oil & gas (downstream)<\/strong><\/td>Screw pump<\/td> Often refers to twin or triple-screw for clean fuel\/lube services<\/td><\/tr> Chemical processing<\/strong><\/td>Progressive cavity pump<\/td> Emphasis on chemical compatibility and metering accuracy<\/td><\/tr> Food & beverage<\/strong><\/td>Progressive cavity pump \/ PC pump<\/td> Sanitary designs; “screw pump” less common<\/td><\/tr> Marine<\/strong><\/td>Screw pump<\/td> Typically refers to twin-screw for fuel and cargo handling<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nRegional Differences<\/h3>\n\n\n\nRegion<\/th> Common Usage<\/th><\/tr><\/thead> North America<\/strong><\/td>“Progressive cavity pump” is dominant in water, wastewater, and general industry<\/td><\/tr> Europe (German-speaking)<\/strong><\/td>“Exzenterschneckenpumpe” (eccentric screw pump) or “Mono-Pumpe”<\/td><\/tr> Europe (UK\/Ireland)<\/strong><\/td>“Progressive cavity pump” and “screw pump” used interchangeably<\/td><\/tr> Middle East<\/strong><\/td>“Screw pump” dominates in oil and gas specifications<\/td><\/tr> Asia-Pacific<\/strong><\/td>Mixed usage; “screw pump” is common, “PC pump” growing in water sector<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nThe Golden Rule<\/h3>\n\n\n\n When you receive a document that says “screw pump,” do not assume. Ask one clarifying question: “Is this a single-screw\/progressive cavity pump, or a twin-screw pump?” If the supplier cannot provide a clear answer on screw configuration, that is itself a warning sign \u2014 proceed with a technical evaluation of the fluid characteristics rather than relying on the supplier’s terminology. This five-second question has prevented countless procurement errors in Changyu Pump’s experience.<\/p>\n\n\n\n
8. What Are Changyu Pump’s Progressive Cavity Pump Products?<\/h2>\n\n\n\nChangyu Pump manufactures the G-type single-screw pump \u2014 a rotary positive displacement pump that is, by all three common names, a progressive cavity pump, a single-screw pump, and a member of the broader screw pump family. The G-type series is designed for the applications where PC pump technology is the required choice: high-viscosity fluids, abrasive slurries, shear-sensitive media, and solids-laden process streams.<\/p>\n\n\n\n
Key Terminology for Changyu G-Type<\/h3>\n\n\n\n When you see the Changyu G-type described in any of the following ways, it refers to the same pump:<\/p>\n\n\n\n
![\"Progressive](\"https:\/\/changyupump.com\/wp-content\/uploads\/2026\/06\/Progressive-Cavity-Pump-vs-Screw-Pump-Whats-the-Difference.webp\")
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<\/figure>\n\n\n\n![\"Progressive](\"https:\/\/changyupump.com\/wp-content\/uploads\/2026\/05\/Screw-pump-1-1024x768.webp\")
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