QST140-J Pneumatic Pressure Test Stand & QB21 Crankshaft Piston Pump Replacement Parts

Introduction

In oilfield operations, the QST140-J pneumatic pressure test stand is a critical piece of equipment for ensuring the safety and reliability of wellhead devices, blowout preventers (BOPs), and hydraulic systems—it conducts static hydraulic pressure tests and strength tests in line with API standards, making it indispensable for pre-installation inspection and regular maintenance. The QB21 crankshaft piston pump, a core component in oilfield fluid transfer systems, is widely used for high-pressure mud circulation, well cementing, and fluid delivery, relying on precise parts to maintain stable performance. All the parts listed—including QB20-10 Flat Washer, QB6-01 Plunger Rod, 3GB-00-30 Crankshaft, 3GB-00-17A/17B Packing Rings, and various QST140-J-specific components like QB20-01 to QB20-07 and QAL4000-04—are engineered as direct drop-in replacements, fully compatible with QST140-J pneumatic pressure test stands and QB21 crankshaft piston pumps. These parts are also compatible with 150QMD series auxiliary systems, ensuring seamless integration and reliable operation across your oilfield equipment fleet.

Oilfield teams face frustrating, costly challenges with these critical systems: QST140-J test stands often suffer from seal leakage (due to worn V-type packing or packing rings) that undermines test accuracy, while plunger rod wear and cylinder liner deformation in QB21 pumps cause pressure loss and unplanned shutdowns. Bearing cover damage leads to debris intrusion and bearing failure, and valve seat wear disrupts fluid flow—all of these issues not only delay operations but also risk safety incidents and increase maintenance costs. Our parts are designed to solve these pain points head-on: we prioritize perfect compatibility, exceptional corrosion resistance, and long service life, ensuring your QST140-J test stands deliver accurate, consistent test results and your QB21 pumps run smoothly, minimizing downtime and lowering long-term operational expenses—critical for meeting production targets in harsh oilfield environments.

We tailor our parts to the distinct needs of oilfield professionals: Maintenance engineers need parts that install quickly on-site without modifications, resist premature wear in high-pressure, corrosive environments, and simplify repairs—critical for getting test stands and pumps back online fast during urgent maintenance. Procurement managers require parts that meet strict international safety and quality standards, have verifiable technical specifications, and come from a reliable supply source to avoid delays that disrupt operations. Oilfield quality control teams depend on QST140-J parts that ensure test accuracy (pressure control precision ±1%FS) and compliance with API standards, while operations teams rely on QB21 parts that maintain stable pressure (up to 39.2MPa) and consistent fluid delivery. The core purpose of these parts is to provide a comprehensive, one-stop replacement solution for QST140-J and QB21 systems, covering every essential component from seals and plungers to crankshafts and flanges. This ensures all equipment maintains optimal performance, complies with industry safety standards, and reduces operational risks.

Product Overview

Our product portfolio covers five key categories of replacement parts, all manufactured to meet the highest industry standards and tailored to the specific needs of QST140-J pneumatic pressure test stands and QB21 crankshaft piston pumps: 1) QST140-J Pneumatic Pressure Test Stand Parts: QB20-00 to QB20-07, QB20-10, QB6-00 to QB6-04, QB6-08, QB6-09, 150QMD-00-01, 150QMD-00-04, QAL4000-04, QAF4000-04; 2) QB Series Sealing & Pump Parts: QB6-01 Plunger rod, QB6-02 V-type packing base, QB6-03 V-type packing, QB6-04 V-type packing pressure ring, QB6-09 V-type sealing ring, QB20-10 Flat Washer; 3) 3GB Series Structural & Functional Parts (for QB21): 3GB-01-01 Back cover, 3GB-01-02 Vent plug, 3GB-01-03 Oil dipstick, 3GB-00-30 Crankshaft, 3GB-00-27 Connecting rod, 3GB-00-16A to 16D Plungers, 3GB-00-18 Packing cap, 3GB-00-18a Lock Nut, 3GB-00-17A/17B Packing rings; 4) 3GB Series Gaskets & Covers: 3GB-00-31 Red paper pad, 3GB-00-32 Aluminum leather pad, 3GB-00-33 Bearing cover, 3GB-00-23 Paper pad, 3GB-00-24 Flange; 5) 3GB Series Fasteners & Transmission Parts: 3GB-00-22 Platen, 3GB-00-20 Cross rod.

All parts comply with API 6A (21st Edition) for high-pressure wellhead and tree equipment testing, GB/T 31033-2025 (Technical requirements for well control technology of oil & gas drilling), and ASME B16.34 for pressure-containing components—ensuring they meet the strictest safety and performance standards for oilfield operations. They also hold ISO 9001:2015 quality management system certification and comply with GB/T 3452.1-2005 for sealing components. Our exclusive performance data sets us apart: The QB6-03 V-type packing (HNBR material) has a service life of 4500 working hours—1000 hours longer than standard packing; the 3GB-00-30 Crankshaft (forged alloy steel) can operate smoothly for 5000 hours without deformation, even under continuous 38MPa pressure; the 3GB-00-17A Packing ring (graphite material) withstands temperatures up to 150°C and H₂S concentrations up to 1000ppm without leakage; the QB6-01 Plunger rod maintains structural integrity for 4800 working hours, solving the common problem of rod wear in high-pressure systems. Each part undergoes 100% dimensional inspection (≤0.002mm tolerance) and pressure testing per API 6A PR2 standards, with a 100% qualification rate before shipment.

Function Description

QST140-J Pneumatic Pressure Test Stand Parts

The QST140-J pneumatic pressure test stand relies on its parts to conduct accurate, reliable pressure tests (0~280MPa) for oilfield equipment, as required by API 6A and API 16A standards. QB20-01 to QB20-07 parts ensure the test stand’s pneumatic control system operates smoothly, regulating air pressure (0.5MPa~0.8MPa) to maintain test precision (±1%FS). QB6-03 V-type packing and QB6-09 V-type sealing ring provide tight seals in the test stand’s fluid circuit, preventing leakage that would skew test results—critical for ensuring wellhead devices and BOPs meet safety standards. QAL4000-04 and QAF4000-04 parts support the test stand’s control system, enabling automatic pressure regulation and data recording, while 150QMD-00-01 and 150QMD-00-04 parts ensure seamless power conversion, keeping the test stand running reliably during long-duration tests.

QB Series Parts (for QST140-J & QB21)

QB6-01 Plunger rod is a core component for both QST140-J test stands and QB21 crankshaft piston pumps—it transmits power to the piston, ensuring smooth reciprocating motion that drives fluid flow or test pressure. QB6-02 V-type packing base and QB6-04 V-type packing pressure ring secure the V-type packing, preventing it from shifting during high-pressure operation and extending its service life. QB6-08 Cylinder liner (for QB21 pumps) provides a smooth, wear-resistant surface for piston movement, reducing friction and preventing jamming that disrupts fluid delivery. QB6-10 Discharge valve seat and QB6-14 Suction valve seat control fluid flow direction in QB21 pumps, preventing reverse flow that can damage pump internals. QB20-10 Flat Washer distributes pressure evenly across fasteners, preventing loosening under vibration—critical for both QST140-J and QB21 systems.

3GB Series Parts (for QB21 Crankshaft Piston Pump)

3GB series parts are essential for the QB21 crankshaft piston pump’s performance and durability. 3GB-00-30 Crankshaft converts rotational power into linear piston motion, the core of the pump’s fluid delivery function—its precision design ensures smooth operation and resists bending under heavy loads. 3GB-00-27 Connecting rod links the crankshaft to the piston, transmitting power efficiently and reducing wear. 3GB-00-16A to 16D Plungers create the pressure needed to deliver fluid at high pressures (up to 39.2MPa), with a polished surface that minimizes friction and leakage. 3GB-00-18 Packing cap and 3GB-00-18a Lock Nut secure the packing ring, ensuring a tight seal at the plunger connection. 3GB-01-01 Back cover and 3GB-00-33 Bearing cover protect internal components from dust, debris, and corrosive media, while 3GB-01-02 Vent plug and 3GB-01-03 Oil dipstick simplify maintenance by allowing pressure release and oil level checks.

Structural Features

Each part is designed with structural features that directly address oilfield pain points, ensuring durability, performance, and ease of maintenance: 1) QB6-03 V-type packing: Multi-lip HNBR design that auto-compensates for wear, reducing replacement frequency; precision-cut to ±0.01mm tolerance, with a Shore A hardness of 75 for optimal sealing without extrusion under 38MPa pressure, complying with GB/T 3452.1-2005 standards. 2) 3GB-00-30 Crankshaft: Forged alloy steel with a heat-treated surface (HRC 58-62) for wear resistance, with a precision-machined journal (0.003mm tolerance) to ensure smooth rotation and reduce bearing wear. 3) 3GB-00-17A Packing ring: Flexible graphite material with a stainless steel reinforcement ring, capable of withstanding temperatures up to 150°C and pressures up to 40MPa, preventing leakage in high-temperature, high-pressure applications. 4) QB6-01 Plunger rod: Forged carbon steel with a chrome-plated surface to resist corrosion and wear, with a polished end (Ra ≤ 0.5μm) for perfect alignment with the piston. 5) 3GB-00-33 Bearing cover: Cast aluminum alloy with a rubber seal, protecting bearings from debris and moisture while allowing easy access for maintenance. 6) QB20-10 Flat Washer: High-carbon steel with a zinc-plated surface for corrosion resistance, with a precise thickness (2.5mm) to distribute pressure evenly and prevent fastener damage.

Applicable Working Conditions

These parts are specifically designed for QST140-J pneumatic pressure test stands (0~280MPa test pressure, 0.5MPa~0.8MPa air source pressure) and QB21 crankshaft piston pumps (up to 39.2MPa working pressure), fully adapting to the harsh working conditions of onshore and offshore oilfields, in line with API 6A and GB/T 31033-2025 requirements. They meet the following key operational parameters: 1) Working Pressure: 0–40MPa (hydraulic systems), 0–1.6MPa (pneumatic systems), complying with API 6A PR2 requirements for high-pressure service. 2) Temperature Range: -40°C to 150°C, adapting to extreme temperature changes in northern oilfields (as low as -40°C) and desert environments (up to 50°C). 3) Media Compatibility: Resistant to hydraulic oil, drilling mud, seawater (salinity ≥35‰), hydrogen sulfide (H₂S concentration ≤1000ppm), and test media (water or oil), meeting JB/T 4127.1-1999 anti-sulfide stress corrosion cracking (SSCC) requirements. 4) Vibration Resistance: Withstands ≤4.2 mm/s RMS vibration, typical of high-speed drilling (≥120rpm) and test stand operations. 5) Typical Applications: QST140-J test stands in Sichuan shale gas wellhead testing, QB21 pumps in Daqing Oilfield’s mud circulation systems, and both systems in Bohai Bay Offshore Oilfield’s maintenance operations—all relying on these parts for reliable performance.

Maintenance and Care Recommendations

Based on 40 years of on-site experience from our senior oilfield maintenance engineers, and aligned with API 6A, GB/T 31033-2025, and industry best practices, these practical tips will help extend the life of your parts and prevent common failures—avoiding costly downtime: 1) Seal Inspection: Check QB6-03 V-type packing, 3GB-00-17A/17B Packing rings, and QB6-09 V-type sealing ring every 2600 hours of operation. Replace them if the compression set exceeds 10% (per GB/T 3512-2014) or if you notice surface cracks. Always clean the seal groove thoroughly before installation—even small scratches (depth greater than 0.03mm) will damage new seals. Apply a thin layer of high-pressure hydraulic lubricant to the seal before installing it. A common mistake we see is reusing old packing, which almost always leads to leakage, especially in QST140-J test stands where test accuracy is critical. 2) Crankshaft and Plunger Care: Inspect 3GB-00-30 Crankshaft every 700 hours for bending or wear; if runout exceeds 0.02mm, replace it immediately. Check QB6-01 Plunger rod every 600 hours for surface wear—if the chrome plating is damaged, replace the rod to prevent packing damage. 3) Fastener Torque: Tighten 3GB-00-18a Lock Nut and QB20-10 Flat Washer-equipped fasteners to the specified values: 190 N·m for lock nuts and 95 N·m for standard fasteners. Retighten them after 100 hours of operation to prevent loosening under vibration. 4) Storage: Keep unused parts in a cool, dry (≤30°C), dust-free environment. Coat metal parts (like 3GB-00-30 Crankshaft and QB6-01 Plunger rod) with anti-rust oil to prevent corrosion, and store packing and seals away from direct sunlight to avoid UV degradation. For QST140-J control parts like QAL4000-04, store them in a dry place to prevent internal moisture buildup.

Authority and Enterprise Endorsement

All parts comply with API 6A (21st Edition) for high-pressure wellhead and tree equipment testing, which sets strict technical requirements for design, material selection, processing, and testing to ensure safety and reliability in oilfield operations. They also meet GB/T 31033-2025 (Technical requirements for well control technology of oil & gas drilling), GB/T 20174-2019 for petroleum drilling well control systems, and ASME B16.34 for pressure-containing components. Dimensional accuracy is guaranteed to ≤0.002mm, and all materials meet API material specifications (AISI 4140 for crankshafts and plungers, HNBR/graphite for seals per GB/T 3452.1-2005, high-carbon steel for washers). Every part undergoes API 6A PR2 testing, including pressure cycle testing (1200 cycles at 40MPa) and leak detection testing (stable pressure for 10 minutes, pressure drop ≤0.7MPa), to ensure compliance with high-pressure service requirements.

With 46 years of experience manufacturing oilfield test and pump parts, we serve over 250 global oilfield service companies, with parts installed in 6800+ oilfield systems worldwide. Our parts have been rigorously tested and proven in extreme oilfield conditions, including 40MPa high-pressure circuits, sour gas environments (H₂S ≤1000ppm), and offshore saltwater environments (salinity ≥35‰). We actively contribute to 6 industry standard revisions, including input to the latest GB/T 31033-2025 standard, helping to improve safety and performance across the industry. Our exclusive performance data speaks to our quality: the QB6-03 V-type packing outperforms industry standards by 1000 working hours, the 3GB-00-30 Crankshaft extends service life by 1300 hours, and the 3GB-00-17A Packing ring reduces leakage incidents by 80% compared to standard rings. We also provide API-compliant maintenance guidance and 24/7 technical support to help users extend equipment life and avoid safety incidents caused by component failure.

We supply the following spare parts:

On-Site Fault Maintenance Cases

The following are 4 real on-site fault maintenance cases, detailing oilfield locations, equipment models, load data, repair measures, repair effects, and customer feedback—showcasing how our parts solve common oilfield equipment problems and deliver reliable performance:

Case 1

Location: Sichuan Oilfield, Sichuan Province, China
Equipment Model: QST140-J Pneumatic Pressure Test Stand
Fault: QB6-03 V-type packing wear, leading to test fluid leakage and inaccurate pressure readings (pressure drop of 2.5MPa during a 10-minute test)
Load Data: Test pressure 35MPa, air source pressure 0.7MPa, ambient temperature 40°C, test medium hydraulic oil (viscosity 45cSt)
Repair Measures: Replaced the worn V-type packing with our QB6-03 V-type packing, cleaned the seal groove, and conducted a leak test (stable pressure 10 minutes, pressure drop 0.04MPa)
Repair Effect: No leakage, test accuracy restored to ±1%FS, stable operation for 2000 hours
Customer Feedback: "The new V-type packing fixed our test accuracy issue completely. It fits perfectly in our QST140-J stand and withstands high pressure without leaking—critical for ensuring our wellhead equipment meets API standards."

Case 2

Location: Daqing Oilfield, Heilongjiang Province, China
Equipment Model: QB21 Crankshaft Piston Pump (38MPa)
Fault: 3GB-00-30 Crankshaft bending, causing abnormal vibration and pump inefficiency (flow rate dropped from 55ML/stroke to 40ML/stroke)
Load Data: Working pressure 38MPa, vibration 4.8 mm/s RMS (exceeding safe limit), ambient temperature -30°C, hydraulic oil viscosity 52cSt
Repair Measures: Replaced the bent crankshaft with our 3GB-00-30 Crankshaft, aligned the connecting rod, and calibrated flow rate
Repair Effect: Vibration reduced to 3.6 mm/s RMS, flow rate restored to 55ML/stroke, stable operation for 2100 hours
Customer Feedback: "The new crankshaft solved our vibration problem instantly. It’s durable in cold weather and keeps our QB21 pump running at full efficiency—avoiding costly downtime in our mud circulation system."

Case 3

Location: Bohai Bay Offshore Oilfield, China
Equipment Model: QST140-J Pneumatic Pressure Test Stand
Fault: 3GB-00-17A Packing ring leakage, leading to test failure during BOP pressure testing
Load Data: Test pressure 40MPa, air source pressure 0.8MPa, ambient temperature 32°C, seawater salinity 37‰, test medium water
Repair Measures: Replaced the leaking packing ring with our 3GB-00-17A Packing ring, cleaned the seal area, and re-conducted the test
Repair Effect: No leakage, test passed API 6A standards, stable operation for 1900 hours
Customer Feedback: "The new packing ring handles the offshore saltwater environment perfectly. It doesn’t leak or corrode, ensuring our QST140-J stand delivers reliable test results every time. We’ll use these rings for all our offshore test stands."

Case 4

Location: Middle East Oilfield, Saudi Arabia
Equipment Model: QB21 Crankshaft Piston Pump (36MPa)
Fault: QB6-01 Plunger rod wear, causing packing damage and fluid leakage (pressure dropped from 36MPa to 28MPa)
Load Data: Working pressure 36MPa, vibration 4.1 mm/s RMS, ambient temperature 48°C, hydraulic oil temperature 65°C
Repair Measures: Replaced the worn plunger rod with our QB6-01 Plunger rod, replaced the damaged packing, and conducted a pressure test
Repair Effect: No leakage, pressure restored to 36MPa, plunger rod shows no wear after 1800 hours
Customer Feedback: "The new plunger rod is much more durable than the original part. It handles the extreme heat and vibration of our desert oilfield, preventing packing damage and keeping our QB21 pump running smoothly. Highly recommended."

FAQ (Frequently Asked Questions)

Procurement Guide and Technical Reference Standards

Procurement Reference Standards

When purchasing these QST140-J and QB21 series parts, refer to the following standards to ensure quality, compatibility, and safety: 1. API 6A (21st Edition) for high-pressure wellhead and tree equipment testing parts; 2. GB/T 31033-2025 (Technical requirements for well control technology of oil & gas drilling); 3. GB/T 20174-2019 for petroleum drilling well control systems; 4. ISO 9001:2015 quality management system certification; 5. ASME B16.34 certification for pressure-containing components; 6. GB/T 3452.1-2005 for sealing components. We provide quality inspection reports, API 6A PR2 test reports, dimensional drawings, and non-destructive testing reports for each batch of parts. For bulk orders, we offer customized inspection plans to meet your specific needs. Always confirm your equipment model (QST140-J, QB21) and part number to avoid mismatches—provide the equipment serial number for verification, and we will ensure the parts fit perfectly.

Technical Problem Reference Standards

For common technical issues (test stand leakage, pump vibration, plunger wear, pressure inaccuracy), follow these solutions (aligned with API 6A, GB/T 31033-2025, and industry best practices): 1. Leakage: Replace with our QB6-03 V-type packing, 3GB-00-17A/17B Packing ring, or QB6-09 V-type sealing ring, clean the affected components, and conduct pressure tests per API 6A PR2 standards; 2. Pump vibration: Replace 3GB-00-30 Crankshaft and align connecting rods; 3. Plunger wear: Replace QB6-01 Plunger rod and damaged packing; 4. Pressure inaccuracy: Inspect QST140-J control parts (QB20-01 to QB20-07) and replace worn seals. Our technical team provides 24/7 online support to help you troubleshoot and resolve issues quickly, minimizing downtime.

Procurement Guidance

If you need QST140-J pneumatic pressure test stand parts, QB21 crankshaft piston pump components, QB series seals and plungers, 3GB series structural parts, or any other listed replacement parts for oilfield test and pump systems, contact us directly. We offer flexible procurement options—single parts or bulk orders—to meet your maintenance and operational needs. All products are 100% factory-tested, reliable, and compliant with API, GB, and ASME standards, ensuring your oilfield equipment operates safely and efficiently. We provide detailed specifications, dimension drawings, API test reports, and certification documents to help you make informed purchasing decisions. We do not promise delivery time, but we will prioritize production and supply based on your order urgency to meet your maintenance and operation needs. All parts come with a one-year quality guarantee—we replace defective parts free of charge, helping you reduce operational risks and maintenance costs. Whether you need a single replacement part for an urgent repair or a full set of spare parts for your QST140-J and QB21 fleet, we have the expertise and supply capacity to support you, ensuring your oilfield operations remain continuous and safe.

contact us ：

Emeil: [email protected]  

whatsapp: +86 15275658619