NOV JWS-340 Special P-5 Valve Pump

The JWS-340 SPECIAL is a reciprocating three-cylinder pump engineered for intermittent high-pressure operations. Its core performance metrics-up to 340 horsepower rated power, a 5-inch (127 mm) stroke, and a maximum discharge pressure of 10,000 PSI (approximately 69 MPa)-enable it to effortlessly handle the most demanding well maintenance challenges. Unlike drilling mud pumps that require prolonged continuous operation, well maintenance pumps are designed to endure extreme pressure cycles in short bursts followed by downtime. This operational pattern imposes extreme fatigue resistance requirements on the pump, particularly on critical pressure-bearing components such as the hydraulic end and crankshaft. Consequently, the JWS-340 SPECIAL's design philosophy fundamentally focuses on maintaining structural integrity and operational reliability under high cyclic stress.

The Optimal Balance of Rigid and Vibration Reduction in the Power Frame Structure

Our JWS-340 SPECIAL pump features an integrated high-strength forged steel power end frame. Unlike the commonly used welded steel or cast iron frames in the industry, this forged steel frame offers unparalleled advantages.

• Exceptional structural rigidity: Unlike welded steel plate frames, the integrated forged frame eliminates welds as potential stress concentration points and weak links. When pumps generate significant reciprocating forces, the forged steel frame demonstrates superior torsional and bending resistance, ensuring precise alignment of the transmission system (crankshaft, pinion shaft). This critical alignment effectively reduces eccentric loading on gears and bearings, thereby significantly extending their service life.
• Optimized strength-to-weight ratio: While materials like ductile iron excel in vibration absorption, forged steel demonstrates significantly higher tensile and yield strengths than cast iron at equivalent weights. Our design achieves structural integrity while reducing the frame's weight, ensuring robustness without bulkiness, thus facilitating on-site installation and transportation.

Transmission System Engineering: Science of Smooth Power Transmission

The transmission system is the core of the power unit, and its design directly determines the pump's operational stability and durability. Through precision metallurgical techniques and gear design, we ensure efficient and reliable power transmission.

Metallurgical Process of Crankshaft and Pinion Shaft

We consistently employ forged alloy steel (42CrMo or modified 4340 alloy steel) for manufacturing crankshafts and pinion shafts. The forging process refines the metal's grain structure, eliminating potential internal shrinkage cavities and porosity in castings. This significantly enhances the material's fatigue strength and toughness, which is essential for crankshafts subjected to high-cycle cyclic loads.

The manufacturing process includes:

1. Precision machining: Key components like shaft necks undergo precision machining to ensure dimensional accuracy and surface finish.
2. Multi-stage heat treatment: The components are hardened by controlled quenching and tempering, while the core is kept tough and plastic to resist impact and prevent brittle fracture.

Gear System: Superiority of the Herringbone Gear

Our JWS-340 SPECIAL pump comes standard with either continuous-tooth or slotted helical gears (double bevel gears). Compared to traditional spur gears or single bevel gears, helical gears offer three key advantages:

• Steady and continuous power transmission: At any moment, multiple tooth pairs engage simultaneously, ensuring smoother torque transfer and effectively reducing operational noise and vibration.
• Elimination of axial thrust: The symmetrical V-shaped tooth profile of the herringbone gears ensures that axial forces generated during torque transmission are mutually neutralized. This fundamentally eliminates axial thrust on the pinion shaft and crankshaft bearings, preventing premature wear caused by excessive axial loads. As a result, the overall reliability and service life of the transmission system are significantly enhanced.
• Higher torque-carrying capacity: The helical gear transmits higher torque than a spur gear or bevel gear of the same size, as the load is distributed more evenly over a wider tooth surface.

Bearing System: Ensuring Long-term Operation

• Bearing configuration: At the main crankshaft bearing position, we select heavy-duty tapered roller bearings. This type of bearing is carefully chosen as it can simultaneously withstand significant radial loads from the connecting rod and potential axial loads, offering superior stability and load-bearing capacity compared to conventional straight roller bearings.

The hydraulic end, the pump's pressure-bearing component, directly determines operational success and cost efficiency through its performance and durability. We recognize that high-quality materials alone cannot withstand cyclic pressures up to 10,000 PSI. To address this, we integrate cutting-edge material science with proprietary manufacturing techniques to develop hydraulic end components featuring exceptional fatigue resistance and unparalleled reliability.

Design of integral forged steel: the pinnacle of pressure vessel

The hydraulic end of our JWS-340 SPECIAL pump features a monoblock design, forged from a single block of premium AISI 4130 or 35CrMo alloy steel. In high-cycle fatigue applications, this design outperforms split modular or cast hydraulic ends. The monoblock structure eliminates all connection welds, bolt holes, and mating surfaces between modules-key areas prone to stress concentration and fatigue crack initiation. By addressing these inherent weaknesses, we ensure maximum structural integrity of the hydraulic end under high-pressure cycling.

The unique manufacturing process creates unmatched fatigue life

Advantages of Autofrettage Process

The self-enhancing process is the core technology in our hydraulic end manufacturing process, and it is the key to its ultra-long fatigue life. This process is not a simple surface treatment, but a deep reshaping of material properties.

• Process Analysis: We apply a controlled instantaneous ultra-high internal pressure, far exceeding the working pressure, to the cross-hole area of the precision-machined hydraulic end, which bears the highest stress internally. This pressure is sufficient to cause plastic deformation (permanent deformation) in the inner wall material of the hole, while the outer layer material remains within the elastic deformation range.
• Stress remolding: When the ultra-high pressure is removed, the elastic outer material tries to recover its original shape, which exerts a strong compressive force on the inner material that has undergone permanent deformation. The result is a considerable depth of permanent compressive residual stress on the surface of the inner hole of the hydraulic end.
• Customer benefits: This pre-installed compressive stress layer functions as a robust protective shield. During pump operation, the majority of tensile stress generated by working pressure is initially absorbed by this preloaded compressive layer. True tensile stress only begins to act on the material when working pressure exceeds this compressive threshold. This mechanism dramatically reduces effective stress amplitudes per pressure cycle, significantly delaying the initiation and propagation of fatigue cracks. As a result, the high-cycle fatigue life of the hydraulic end increases exponentially, while effectively mitigating the risk of stress corrosion cracking.

Precision Heat Treatment and Strict Quality Control

• Optimized heat treatment: We employ a computer-controlled heat treatment program (including normalizing, quenching, and tempering) to process the forged hydraulic end. This ensures the alloy steel achieves an optimal microstructure-combining sufficient hardness for wear resistance with exceptional toughness for impact absorption, achieving a perfect balance of strength and toughness.
• Non-Destructive Testing (NDT): Every hydraulic end product undergoes rigorous multi-stage NDT before leaving the factory. Magnetic Particle Inspection (MPI) detects surface and subsurface micro-cracks, while Ultrasonic Testing (UT) ensures no internal defects such as inclusions or porosity. This comprehensive quality control process guarantees flawless delivery to customers.

Cylinder liner: the first line of defense against wear

High Chromium Bimetallic Cylinder Liner (Perfect Upgrade of Industry Standard)

• Structure and Material: The cylinder liner adopts a double-layer structure. The outer shell is made of high-strength forged steel (e.g. AISI 1045) to withstand high pump pressure, and the inner lining is made of high-chromium cast iron (Cr content> 26%) by centrifugal casting, which has excellent wear resistance and corrosion resistance.
• Manufacturing process: The liner undergoes rigorous heat treatment (quenching and tempering) to achieve uniform hardness of HRC 60-69. Subsequently, the inner bore is precision honed to mirror finish (roughness <Ra 0.2), which not only reduces friction with the piston but also significantly extends its service life.
• Performance: Under standard drilling fluid conditions, it has a reliable service life of over 800 hours, providing solid support for high-intensity operations.

• Materials Science: The lining is made of advanced phase-change toughened zirconia (ZrO3) composite ceramics, which is firmly bonded with the forged steel shell.
• Unparalleled performance: Zirconia ceramics boast exceptional hardness (HRC 90+), with wear resistance, corrosion resistance, and erosion resistance far surpassing any metal. Additionally, they exhibit outstanding thermal stability, maintaining performance under high-temperature and high-pressure conditions.
• Total Cost of Ownership (TCO) advantage: Despite the higher initial procurement cost, zirconia ceramic cylinder liners deliver a significant return on investment. Their service life typically exceeds 4,000 to 8,000 hours, which is 5 to 10 times longer than bimetallic cylinder liners.

Piston: Durability Engineering under Extreme Pressure

• The piston core is made of high-tensile strength forged alloy steel, ensuring structural integrity and deformation resistance even under 10,000-pound pressure.
• Advanced elastomer technology: We utilize proprietary adhesive polyurethane technology. Through chemical bonding, high-performance polyurethane elastomers are securely bonded to metal cores. Compared to traditional mechanical locking pistons, this design effectively prevents adhesive detachment and extrusion under high pressure, ensuring more reliable sealing performance.
• Performance: Our proprietary high-hardness polyurethane formulation delivers exceptional wear resistance, tear resistance, and chemical corrosion resistance across water-based, oil-based, and synthetic-based drilling fluids, while maintaining stable performance in high-temperature environments up to 225-300°F (107-149°C).

Valve and valve seat: the guardian of system pressure

• Materials and Structure: The valve body and seat are integrally forged from high-grade alloy steel (AISI 8620) to achieve maximum strength and impact toughness. The JWS-340 pump is typically equipped with P-4 valve.
• Advanced Surface Hardening Process: We employ a precision carburizing and quenching heat treatment process. This process forms an extremely hard (HRC 58-65) wear-resistant layer on the contact surface between the valve and valve seat, while maintaining sufficient toughness in the internal core.
• High-performance polyurethane valve gaskets: Our proprietary polyurethane material delivers reliable, long-lasting sealing performance while effectively resisting swelling and chemical erosion in various drilling fluids. We provide both standard and high-temperature resistant formulations to meet diverse operational requirements.

Piston rod: the key link of power transmission

• Materials and Forging: The piston rod is made of high-strength 42CrMo forged alloy steel and undergoes full heat treatment to achieve excellent tensile strength and fatigue resistance.
• Advanced surface coating technology (HVOF vs. hard chrome):

Standard configuration: Hard chrome plating, a reliable industry standard.

Advanced OEM specification: HVOF (High-Velocity Oxygen Fuel) tungsten carbide coating. Compared to conventional hard chrome plating, the HVOF coating offers significant advantages:

• Superior hardness and wear resistance: The HVOF coating achieves a hardness exceeding 71 HRC, with wear resistance surpassing that of hard chrome plating by a factor of 128.
• Superior corrosion resistance: The coating produced by HVOF process is dense and pore-free, with extremely high bonding strength to the substrate. Its corrosion resistance far surpasses that of hard chrome coatings with micro-cracks.
• Extended service life: Significantly prolongs the lifespan of the piston rod and its mating packing seal, further reducing maintenance requirements and NPT.

JWS-340 SPECIAL Performance Data

The table below details the performance parameters of the JWS-340 SPECIAL pump across various plunger/piston sizes and rotational speeds. These data serve as the foundation for planning well maintenance operations such as cementing, acidizing, or fracturing, ensuring the pump operates safely and efficiently within its design limits.

Table 1: Performance Specifications of JWS-340 SPECIAL

data sources ：

Performance specifications: Flow rate is calculated based on 100% volumetric efficiency. Required braking horsepower is calculated based on 90% mechanical efficiency. The rated values apply to intermittent operation. The displayed pressure can be sustained for no more than 30 minutes, followed by an equal duration of no-load period, with total operating time not exceeding 4 hours within 24 hours. When the pump is equipped with a piston and cylinder liner, the pressure should not exceed 5000 PSI except in emergency situations or short-term intermittent operation. For plunger pumps, it is recommended to operate at speeds exceeding 225 RPM. However, for piston-equipped pumps, this speed limit is not recommended to ensure maximum cylinder liner and piston lifespan.

Material Specifications and Interchangeability of Fragile Parts

The table below provides a quick reference guide for the procurement and maintenance teams. It clearly demonstrates the material advantages of our OEM products and offers part numbers fully compatible with the original manufacturer, ensuring a simple and accurate ordering process.

Table 2: Material Specifications and Interchangeability of Key Vulnerable Parts

Be your trusted partner

We are committed to being your trusted partner in pursuing operational excellence. We offer not just products, but solutions rooted in deep technical expertise and profound industry insights.

We cordially invite you to contact our technical sales team to discuss your specific application requirements. Our customized Total Cost of Ownership (TCO) analysis will demonstrate through data that choosing our JWS-340 SPECIAL three-cylinder pump and OEM components is the most cost-effective investment to enhance equipment reliability and reduce operational costs.

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