How to calibrate and adjust the safety relief valve on CYZ pump?

Centrifugal pumps lack internal safety valves, so an independent relief valve is mandatory. Set the cracking pressure to 1.05–1.15 times the rated working pressure. During commissioning, start with the discharge valve closed, slowly open the bypass valve until the set pressure is reached, stabilize the gauge reading, and lock the valve position to ensure automatic bypass during overpressure events.

What are the speed reduction rules for CYZ pump when handling high viscosity fluids?

When fluid viscosity exceeds 30 cSt, motor speed must be reduced. According to affinity laws, flow and head vary with the square of speed, while power varies with the cube. Maintaining rated speed at high viscosities causes low suction vacuum leading to cavitation and motor overload. Use VFD control to reduce speed to 85-90% of rated value to balance self-priming efficiency against mechanical load.

How to troubleshoot shaft seal leakage on CYZ pump?

The CYZ uses a tungsten carbide single-face mechanical seal. If leakage is detected, first check for adequate cooling flush fluid and correct flow direction. For packing glands, the standard leakage rate is 10-30 drops per minute; tighten gland bolts by cross-tightening evenly, never locking them in one go. Routine maintenance requires regular bearing box grease replenishment and monitoring seal chamber temperature, as abnormal heating indicates wear or dry running.

CYZ SERIES10 modelsHS: 8413.70.99

CYZ Self-Priming Centrifugal Oil Pump (CYZ Series)

Chemical, Magnetic & Diaphragm Pumps•CYZ

Flow Range: 3.2 ~ 600 m³/h
Head Range: 12 ~ 80 m
Motor Power: 1.5 ~ 132 kW
Model: CYZ-20 → CYZ-200
Customs HS Code: 8413.70.99

WhatsApp Quick Quote Email for Price & DrawingModel-by-Model Technical Specifications ↓

CYZ Self-Priming Centrifugal Oil Pump (CYZ Series)

Hydraulic Principle & Internal Construction

The CYZ series self-priming centrifugal oil pump incorporates an internal gas-liquid separation reservoir that achieves fast self-priming (up to 5 meters) without auxiliary foot valves or priming liquid. Ideal for gasoline, diesel, kerosene, and jet fuel handling in tanker loading racks, airport fueling systems, and marine ballast operations.

Model-by-Model Technical Specifications

Model	Inlet	Outlet	Flow (m³/h)	Head (m)	Speed (rpm)	Motor (kW)
CYZ-20	DN25	DN25	3.2	12	2900	1.5
CYZ-25	DN32	DN32	6	18	2900	2.2
CYZ-32	DN40	DN40	11	20	2900	3
CYZ-40	DN50	DN50	20	25	2900	5.5
CYZ-50	DN65	DN65	30	30	2900	7.5
CYZ-65	DN80	DN80	50	40	2900	11
CYZ-80	DN100	DN100	80	50	2900	18.5
CYZ-100	DN125	DN125	160	60	1450	37
CYZ-150	DN150	DN150	300	70	1450	75
CYZ-200	DN200	DN200	600	80	1450	132

Selection guidance: match your duty point to the closest model below, then confirm with our engineers. Values are rated operating points at the listed speed.

Need Complete Engineering Dimensions & Curves?

Download the official CYZ series 1-page technical datasheet covering all 10 model configurations.

Media Compatibility & Viscosity / Temperature Guide

Medium	Max Viscosity (cSt)	Application Note
Gasoline / Kerosene / Diesel Fuels	50	Non-Sparking Bronze Impeller
Aviation Jet Fuel (Jet A-1 / Kerosene)	30	Airport Jet Fuel Storage Terminals
Marine Cylinder & Turbine Lubricants	320	Marine Tanker Stripping Duty
Refined Petroleum Products (Gasoline / Diesel / Gasoil)	80	Marine Dock Loading & Unloading

International Benchmark & Interchange Guide

International Benchmarks

DESMI (Denmark) rotary/centrifugal self-priming pumps
Svanehøj / Fristam self-priming pumps

Interchange Note

Self-priming centrifugal fuel pump. Interchangeable with Gorman-Rupp 10 series and MP Pumps self-priming centrifugal units for fuel unloading and marine duty.

Materials & Shaft Seal Selection Guide

Engineering metallurgy and seal selection advice for corrosiveness and temperature: CYZ pump casings are recommended in HT250 or QT400-18 cast iron for mineral oils and hydraulic fluids at ambient to 80°C. For fuels containing sulfur or highly corrosive media, upgrade to 304 or 316L stainless steel. For shaft seals, tungsten carbide mechanical seals are preferred for general wear resistance and longevity. Packing glands with cooling flush are suitable for high-temperature or particulate-laden applications. Ensure all sealing materials are compatible with the specific fluid to prevent rubber degradation and leakage.

Casing & Housing Materials: HT250 Gray Cast Iron (GG25)AISI 304 Stainless Steel
Rotor / Gear / Screw Elements: Explosion-Proof Wear-Resistant Tin-Bronze ImpellerAISI 304 Impeller
Shaft Sealing Options: Tungsten Carbide Single Mechanical Seal

Engineering FAQ

Ensure suction pipe diameter matches or exceeds the impeller inlet to minimize velocity head losses. Install at least 3 pipe diameters of straight run before the inlet to stabilize flow; avoid elbows and valves on the suction side. Although CYZ pumps have self-priming capabilities, NPSHa must exceed NPSHr by a minimum safety margin of 0.5 meters to prevent cavitation damage during startup after initial priming.

📐 Engineering Selection Methodology

Correct pump selection starts from the fluid, not the pump. Confirm the medium name and actual viscosity at working temperature, the required flow and differential pressure or head, suction conditions (flooded or lift), and whether the fluid crystallizes, shears, contains particles or gas. Positive displacement pumps must always be protected by a relief valve or pressure bypass on the discharge line, and must never be started against a closed valve unless a bypass is fitted. For viscous duties, derate rotational speed to preserve volumetric efficiency; for crystallizing or high-freezing-point media, specify jacketed casings with steam or thermal-oil heating. Our engineers verify each enquiry against these rules before quoting.

🏭 Manufacturing & Quality Control

Castings are produced in our own foundry cluster with material certificates for each heat number. Gear profiles, screw threads and rotor lobes are hobbed, ground and wire-cut to tolerance, then assembled with matched bearing sets. Before dispatch every pump passes casing hydrostatic pressure testing, a run-in test at rated speed on an oil bench, and relief valve cracking-pressure verification; test records are archived against the pump serial number and can be supplied with the shipment.

📦 Export Packaging & Delivery

Pumps are preserved with anti-rust coating, flanges blanked, and packed in export-grade plywood cases with steel strapping for sea freight. Document packs include operating manual, performance test record, packing list and material certificates on request. Standard models ship from stock; engineered configurations typically require 15-35 days depending on casing material and seal options. Spare rotor sets, seal kits and relief valve assemblies can be quoted together with the base pump.

Typical Applications & Industry Use Cases

The media compatibility table above maps directly to real industry duties. In lubrication circuits, size the pump for continuous duty at 70-80% of rated flow to leave margin for viscosity drift as oil warms up. In chemical transfer, confirm the medium's specific gravity and whether it is shear-sensitive before fixing rotational speed. In food and sanitary service, schedule CIP cycles around the product changeover plan and verify elastomer compliance with the relevant food-contact regulation in your market. In hot oil and asphalt service, always pre-heat the casing to the medium temperature before start-up so internal clearances are at operating dimension - a cold start against solidified product is the single most common cause of gear pump failures reported from the field.

Commissioning & Maintenance Guidance

Before first start: verify rotation direction, fill the casing with medium, open the discharge bypass, and jog the motor to confirm free rotation. Check the relief valve setting against the system design pressure and lock the adjuster. During the first hour, record suction and discharge pressures, medium temperature, and motor current - deviations from the quotation duty point usually indicate suction restriction or an over-throttled discharge line. Routine maintenance intervals: inspect the shaft seal weekly during the first month, then monthly; check coupling alignment after any pipe work; drain and inspect the bearing housing annually. Keep a log of running hours so rotors, bearings and seals can be replaced on condition rather than after failure.

Troubleshooting Quick Reference

No delivery or loss of prime: check suction line for air ingress, verify foot valve and strainer are submerged and clean, and confirm the casing is primed for pumps without self-priming capability. Flow below nameplate: verify actual rotational speed against the data sheet, confirm medium viscosity is within the rated band, and inspect internal clearances for wear if the pump has long service hours. Abnormal noise or vibration: usually coupling misalignment, cavitation from excessive suction lift, or foreign matter in the pumping chamber. Seal leakage: confirm flush plan and seal face condition; never run a mechanical seal dry. Motor overload: check for over-viscous medium at start-up temperature and confirm the relief valve is not set above the motor's capability. For anything beyond these basics, send us the serial number and symptom - our engineers will respond with a diagnosis.

📋 Standards, Testing & Documentation

Gear pumps in this catalog are designed and acceptance-tested with reference to JB/T 6434 (external gear pumps), three-screw pumps to GB/T 10886, centrifugal chemical pumps to ISO 2858, and sealless or screw pumps to the relevant API 676 guidance, with mechanical seals supplied to API 682 configurations on request. Sanitary models are manufactured with surface finishes suitable for FDA / 3A style hygienic duties. Each shipment can include: performance test record against the quoted duty point, hydrostatic test certificate, material certificates for pressure-retaining parts, operating and maintenance manual, and a dimensional drawing with flange table. Tell us which standards your project specification cites and we will align the documentation pack accordingly.

🔧 Spare Parts & After-Sales Support

Every pump model page doubles as a spare-parts reference: rotor and gear sets, bearing and thrust assemblies, complete seal cartridges, relief valve kits and jacket gasket sets are manufactured in-house to the same drawings as the original build - so spares ordered years later still match. Recommended commissioning spares are one seal set and one gasket set per pump; for critical continuous-duty installations we recommend a full rotor set held on site. When ordering spares, quote the pump serial number and nameplate data so the correct material and clearance class is supplied. Technical support in English is available by email during China business hours, with video call diagnostics available for installation and commissioning issues.

ℹ️ Technical data on this page is sourced from the manufacturer's engineering database and applicable standards (JB/T 6434, GB/T 10886, ISO 2858, API 676). Final selection must be confirmed by our engineers against your actual duty conditions.

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