NOV JWS-340 Special Pump

JWS-340 SPECIAL is a reciprocating triplex pump designed for intermittent high-pressure operation. Its core performance parameters-rated power of up to 340 horsepower, a 5-inch (127 mm) stroke and maximum discharge pressure of up to 10,000 PSI-make it easily adaptable to the most demanding workover challenges. Unlike drilling mud pumps, which require continuous operation for a long time, workover pumps are characterized by extremely high pressure cycling in a short period of time, followed by a shutdown period. This kind of working mode puts forward the extreme requirements for the anti-fatigue performance of the pump, especially for the key pressure-bearing components such as the hydraulic end and the crankshaft. Therefore, the design philosophy of JWS-340 SPECIAL is fundamentally focused on maintaining structural integrity and operational reliability under high cyclic stresses.

Power end frame construction: optimal balance of rigidity and vibration reduction

Our JWS-340 SPECIAL pump uses an all-in-one high strength forged steel power end housing. Compared with the common welded steel frame or cast iron frame in the industry, the forged steel frame has incomparable advantages.

Superior structural rigidity: the one-piece forging frame eliminates the potential stress concentration and weakness of welds compared to a frame made of welded steel plates. The forged steel frame provides greater resistance to torsion and bending, ensuring accurate alignment of the drive train (crankshaft, pinion shaft) when the pump is operating with a large reciprocating force. This precise alignment is essential to effectively reduce the eccentric load of gears and bearings, thus significantly extending their service life.

Optimized strength-to-weight ratio: although materials such as ductile iron have excellent vibration absorption properties, the tensile strength and yield strength of forged steel far exceed those of cast iron at the same weight. Our design optimizes the weight of the frame on the premise of ensuring sufficient structural strength, making it both strong and not too bulky, and convenient for on-site installation and transportation.

Drivetrain Engineering: the science of smooth power transmission

The transmission system is the core of the power end, and its design directly determines the stability and durability of the pump. We use precision metallurgy and gear design to ensure efficient and reliable power transmission.

Metallurgical process of crankshaft and pinion shaft

We insist on using forged alloy steel (42CrMo or modified 4340) for crankshafts and pinion shafts. The forging process can refine the grain structure of the metal, eliminate the internal shrinkage cavity and porosity in the casting, and greatly improve the fatigue strength and toughness of the material, this is crucial for crankshafts subjected to high cycle loads.

The manufacturing process includes:

Precision Machining: machining the key parts such as journal precisely to ensure the dimensional accuracy and surface finish.

Multi-stage heat treatment: using strictly controlled quenching and tempering process, so that the surface of the parts to form a hard wear-resistant hardened layer, while maintaining good toughness and plasticity of the core to resist impact load and prevent brittle fracture.

Gear system: the preeminent advantage of herringbone gears

Our JWS-340 SPECIAL pumps come standard with continuous toothed or slotted herringbone gears (double helical) . Herringbone gears offer three core advantages over conventional spur or helical gears:

Smooth and continuous power transmission: at any time, there are many teeth meshing at the same time, making torque transmission more smooth, effectively reducing the noise and vibration.

Eliminate the axial thrust: herringbone gear symmetrical"V"-shaped tooth shape in the transmission of torque generated in the left and right direction of the axial force offset each other. This fundamentally eliminates the axial thrust on the pinion shaft and crankshaft bearing, avoids the premature wear of the bearing caused by the additional axial load, and significantly improves the overall reliability and life of the transmission system.

Higher torque capacity: herringbone gears can transmit higher torque than spur or helical gears of the same size because the load is more evenly distributed across the wider tooth surface.

Bearing system: ensures long-lasting operation

Bearing configuration: in the crankshaft main bearing position, we use heavy-duty tapered roller bearings. This bearing type was carefully selected because it is able to withstand both the large radial load from the connecting rod and the potential axial load, providing superior stability and load capacity than ordinary straight roller bearings.

The hydraulic end is the part of the pump that directly bears the extreme working pressure, and its performance and service life are directly related to the success or failure of the operation and the cost. We know that high-quality materials alone are not sufficient to handle cyclic stresses up to 10,000 PSI. Therefore, we combine cutting-edge material science with proprietary manufacturing processes to create a hydraulic end with ultra-long fatigue life and superior reliability.

Integral forged steel design: the pinnacle of pressure vessels

The hydraulic end of our JWS-340 SPECIAL pump has a Mono-block design and is forged from a single piece of premium AISI 4130 or 35CrMo alloy steel. In high cycle fatigue applications, this design is superior to split modular or cast hydraulic ends. The integrated structure fundamentally eliminates the welds, bolt holes and joint surfaces between modules, which are the high-incidence areas of stress concentration and the source of fatigue crack initiation. By eliminating these inherent weaknesses, we maximize the structural integrity of the hydraulic end under high-pressure circulation.

Proprietary manufacturing process for unrivalled fatigue life

Advantages of Autofrettage process

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

Process Analysis: we will precisely machine the hydraulic end and apply a controlled, instantaneous ultrahigh internal pressure far beyond the working pressure to the area of the crosshole that is subjected to the highest internal stress. This pressure is sufficient to cause plastic deformation (permanent deformation) of the material on the inner wall of the hole, while the material on the outer wall remains in the elastic deformation range.

Stress remolding: when the ultra-high pressure is removed, the outer layer material in the elastic state tries to recover to its original state, thus exerting a strong squeezing effect on the inner layer material that has undergone permanent deformation. The final result is that a layer of permanent compressive residual stress with considerable depth is formed on the surface of the inner hole of the hydraulic end.

Customer benefit: this preset compressive stress layer acts as a strong"Shield". In the actual operation of the pump, most of the tensile stress generated by the operating pressure is first used to offset this preset compressive stress. Only when the working pressure exceeds this compressive stress value does the material itself begin to bear true tensile stress. This mechanism greatly reduces the effective stress amplitude in each pressure cycle, which significantly delays the initiation and propagation of fatigue cracks, and makes the high-cycle fatigue life of the hydraulic end increase exponentially, and the risk of stress corrosion cracking is effectively suppressed.

Precision heat treatment and strict quality control

Optimized heat treatment: we use a computer-controlled heat treatment program (including normalizing, quenching and tempering) to treat the hydraulic end of the forging. This ensures that the alloy steel has the best microstructure-a perfect balance of strength and toughness, with sufficient hardness to resist wear and superior toughness to absorb impact.

Non-destructive testing (NDT) : every hydraulic end must pass our rigorous multi-stage NDT before it leaves the factory. We use magnetic particle inspection (MPI) to detect small cracks on and near the surface, and ultrasonic inspection (UT) to ensure that the material is free of any bulk defects such as inclusions and porosity. This comprehensive quality control process ensures that every product delivered to the customer is flawless.

Cylinder liners: the first line of defense against abrasion

High chromium bimetal cylinder liner (perfect upgrade of industry standard)

Construction and material: the cylinder liner is made of two layers. The casing is made of high strength forged steel such as AISI 1045 to withstand high pump pressure and the lining is made of centrifugally cast high chromium cast iron (CR > 26%) with excellent wear resistance and corrosion resistance.

Manufacturing Process: the lining is subjected to a rigorous heat treatment (quenching and tempering) , so that the overall hardness of the uniform HRC 60-69. Subsequently, the bore is precision honed to a mirror-level finish (roughness $< R a 0.2) , which not only reduces friction with the piston but also significantly extends its life.

Performance: under the standard drilling fluid condition, its reliable service life surpasses 800 hours, has provided the solid safeguard for the high strength work.

Zirconia ceramic cylinder liner (Ultimate TCO solution)

Materials Science: Advanced Phase transformation toughened zirconia (ZRO3) composite ceramic material is used to make the inner lining, which is firmly combined with the forged steel shell.

Unparalleled Performance: Zirconia ceramics with high hardness (HRC 90 +) , its wear resistance, corrosion resistance and erosion resistance far beyond any metal materials. At the same time, it also has excellent thermal stability, can maintain stable performance in high temperature and high pressure environment.

Total cost advantage: despite the high initial purchase cost, the return on investment for zirconia ceramic cylinder liners is enormous. The service life is typically 4,000 to 8,000 hours or more, 5 to 10 times that of a bimetallic liner.

Pistons: durability engineering under extreme pressures

Structural design: the piston core is made of high tensile strength forged alloy steel, which ensures the structural integrity and no deformation under 10,000 lbs pressure.

Advanced Elastomer technology: our proprietary bonded polyurethane design. The high-performance polyurethane elastomer was firmly bonded to the metal core by chemical bonding process. Compared with the traditional mechanical locking piston, this design can effectively prevent the phenomenon of degumming and extrusion under high pressure, and the sealing performance is more reliable.

Performance: our proprietary high-hardness polyurethane formula has excellent wear resistance, tear resistance and chemical resistance to water-based, oil-based and synthetic-based drilling fluids, and can work stably in high temperature environment up to 225-300 °F (about 107-149 °C) .

Valve and seat: The Guardian of system pressure

Material and construction: body and seat are forged from high quality alloy steel (AISI 8620) for maximum strength and impact toughness. The JWS-340 pump is normally supplied
P-4 valve.

Advanced surface hardening process: we use precision carburizing and quenching processes. The process creates an extremely hard (HRC 58-65) wear-resistant layer on the contact surface of the valve and seat, while maintaining sufficient toughness of the internal core.

High-performance polyurethane valve rubber: our proprietary polyurethane valve rubber material, can provide reliable, lasting sealing effect, effectively resist the swelling and chemical erosion in a variety of drilling fluid. We offer both standard and high-temperature formulations to suit a wide variety of operating conditions.

Piston rod: Key Link for power transmission

Material and forging: the piston rod is made of high strength 42CrMo forged alloy steel and heat treated in one piece for superior tensile strength and fatigue resistance.

Advanced surface coating technology (HVOF vs. hard chromium) :

Standard configuration: hard chrome plating as a reliable industry standard.

Advanced OEM configuration: HVOF (high-speed oxygen fuel) tungsten carbide coating. Compared to conventional hard chromium coatings, HVOF coatings have an overwhelming advantage:

Ultra-high hardness and wear resistance: HVOF coating hardness of up to 71hrc, wear resistance far beyond the hard chromium coating.

Excellent corrosion resistance: the HVOF coating is dense, non-porous, and has high bonding strength with the substrate. Its corrosion resistance is much better than that of the hard chromium coating with microcracks.

Longer Life: significantly extends the life of the piston rod itself and its mating packing seals, further reducing maintenance requirements and NPT.

Performance specifications and interchangeability

JWS-340 SPECIAL performance data

The following table details the performance parameters of the JWS-340 SPECIAL pump at various plunger/piston sizes and speeds. These data are the basis for planning workover operations such as cementing, acidizing or fracturing to ensure that the pump operates safely and efficiently within its design limits.

Table 1: JWS-340 SPECIAL performance specifications

Sources of data:

Performance data description: flow rate is calculated based on 100% volumetric efficiency. The required brake horsepower is calculated based on 90% mechanical efficiency. The rating applies to intermittent work. The pressure shown is sustained for not more than 30 minutes, followed by an equivalent period of no-load operation, with a total working time of not more than 4 hours in a 24-hour period. When the pump is equipped with a piston and cylinder liner, the pressure shall not exceed 5000 PSI except in emergency or for short-term intermittent operation. For piston pumps, more than 225 RPM is recommended, but not for pumps with pistons for maximum liner and piston life.

Material specification and interchangeability of wearing parts

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

Table 2: material specifications and interchangeability of key perishables

To be your reliable partner

We are committed to being a reliable partner in your pursuit of operational excellence. We offer not only products, but also solutions based on deep technology accumulation and deep understanding of the industry.

We sincerely invite you to contact our technical sales team to discuss in depth your specific application needs. We will provide you with customized TCO analysis with data proof to select our JWS-340 Special Triplex Pump and OEM components, will be the wisest investment you can make in improving equipment reliability and reducing operating costs.

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