Your location:
The K7Z is an adjustable-pitch axial fan blade covering 180-1254 mm with 3 to 16 blades on the Z-3 hub, in PAG or conductive PAGAS.
The K7Z is an adjustable-pitch axial fan blade for high performance moving-air units, covering 180-1254 mm with 3-16 blades on the Z-3 hub. It is the large-diameter end of the UTEK-DELE blade range: a slow, wide impeller that moves a high air volume with low power consumption and low blade-passing noise.
Blades are moulded in PAG for general heavy-load cooling, in conductive PAGAS where static discharge has to be avoided, and cast in aluminium ADC12 for high-temperature duties. Each blade set is assembled on its hub and balanced before shipment, so a replacement behaves like the fan it replaces.
Adjustable pitch — the blade angle is set at assembly to the duty point and recorded for repeat orders
Diameter range 180-1254 mm with 3-16 blades on the Z-3 hub
Three blade materials: PAG, conductive PAGAS and die-cast aluminium ADC12
Balanced as an impeller on a hand laser balancing machine before shipment
Suitable for both new fans and replacement of an existing large fan
| Item | Specification |
|---|---|
| Model | K7Z |
| Blade type | Adjustable pitch (angle set at assembly) |
| Diameter range | 180-1254 mm |
| Blade count | 3-16 |
| Hub | Z-3 family |
| Blade materials | PAG / conductive PAGAS / ALU (ADC12) |
| Balancing | Dynamic balancing on a hand laser balancing machine |
| Applications | Moving-air units, cooling towers, industrial ventilation, livestock housing |
| Material | Composition | Temperature range | Typical duty |
|---|---|---|---|
| PAG | PA6 with 30% glass fibre | -40 °C to 110 °C | General heavy-load blade |
| PAGAS | PA6 with 15% carbon fibre and 15% glass fibre (conductive) | -30 °C to 100 °C | Dust and gas atmospheres where static discharge must be avoided |
The K7Z belongs to the K Series range. The related pages are K Series big airflow fans, K6Z and K7Z fans, industrial axial fan blades, industrial axial fan impellers.
For the complete fan version of this blade, including the assembled fan and its application pages, see the K7Z complete fan page. This page covers the K7Z blade and impeller side — replacing a blade set, matching the hub and reproducing the original duty point.
Support starts before the blade is quoted. The points below are the ones that decide whether an K7Z fits an existing fan or a new cooling pack, and they are the same checks used for OEM programs and retrofit work.
Diameter — set by the fan ring or shroud that is available, since this fixes the achievable air volume at the working speed
Airflow and static pressure — the duty point the fan has to meet at the working speed
Blade count — raised for pressure and lower airflow, lowered for maximum air volume and lower blade-passing noise
Material — decided by the maximum air temperature and by whether static discharge has to be avoided
Hub and shaft interface — confirmed before the blade set is released for production
Selection follows that order because changing a later step normally means going back to the first: blade count and hub rating both limit what a given diameter can carry at the working speed.
A replacement does not have to match a drawing, only the interface that already exists on the machine:
Connection holes and bushings are machined to match the existing hub, so the blade set can be fitted
The blade count and blade type of the original fan are confirmed, which preserves the original airflow and noise level
The hub family is verified against the shaft, including the taper bush where one is used
The assembled impeller is balanced before shipment, so no balancing rig is needed on site
Every impeller is balanced on a hand laser balancing machine before shipment. On a large-diameter blade this matters more than on a small one, because imbalance grows with diameter and blade mass and shows up as vibration, fastener loosening and bearing wear. Balance settings and blade count are recorded so a later replacement can be matched to the same condition.
Blade count, blade profile, pitch setting, hub family and material can all be fixed for an OEM program, and an existing fan can be reviewed when the cooling pack or the ventilation duty is revised:
Blade count and pitch angle set to the required airflow and pressure
Hub and shaft interface matched to the existing drive
Material selected against temperature and atmosphere (PAG, conductive PAGAS, ALU)
Replacement programs where only the blades are renewed and the hub stays in service
Material and test records are available for projects that require them: certificate of analysis for the material and for the finished PAGAS blade, UV resistance and fire behaviour reports for PAG, and explosion-proof type test reports where conductive blades are used in a classified atmosphere. Certificate and report copies are provided on request rather than published as current certifications.
The K7Z is specified where a large air volume has to be moved continuously with moderate pressure: applications where a large slow impeller is more efficient and quieter than a smaller fast fan. The duties below are the ones this blade is normally ordered for.
High airflow fans where the K blade family is already used
Cooling towers and industrial heat exchangers
Engine cooling on off-highway machinery
Replacement of existing K7Z blade sets
| Application | Duty characteristic | Diameter | Blades | Hub | Material |
|---|---|---|---|---|---|
| High airflow cooling | Large volume, moderate pressure | 560-1254 mm | 6-10 | Z-3 | PAG / PAGAS |
| Cooling tower | Continuous duty | 630-1254 mm | 8-12 | Z-3 | PAG |
| Conductive atmosphere | Static discharge avoided | 180-1254 mm | 3-16 | Z-3 | PAGAS |
| Replacement / retrofit | Match existing hub and shaft | As measured | As original | Z-3 | As original |
The matrix is a starting point rather than a final specification: diameter is confirmed against the installation, then blade count and material are fixed against the duty point and the air temperature.
Most orders for this blade are replacements rather than new fans, and they follow the same pattern:
A large fan in a cooling tower or moving-air unit fails, and the hub and shaft are still serviceable
The original diameter and blade count are confirmed from the fan records or measured on site
Connection holes and bushings are machined to the existing hub so the blade set fits without modification
The replacement impeller is balanced before shipment and the fan returns to service without on-site balancing
Where the whole hub has to be renewed, the hub is matched to the existing shaft instead
Because the blade family is unchanged in production, a fan commissioned years ago can be re-bladed to the same airflow and noise condition, which keeps a fleet of machines on one specification.
Installation and commissioning support covers the practical points: blade angle set at assembly, hub clamping and fastener checks, and confirmation that the fan reaches its duty point after the machine is back in service. Field installation for this blade is shown in the product video on the Product Features tab.
UTEK-DELE (Changzhou Dele Ventilation and Heat Dissipation Technology Co., Ltd.) designs and manufactures axial fan blades, impellers and complete fan assemblies. The range covers moulded PAG and conductive PAGAS blades, die-cast aluminium blades, hubs from H-6 to H-12 and the Z and W families, and finished impellers from 180 mm up to 2200 mm for engine cooling, cooling towers and industrial ventilation.
Production, balancing and inspection are carried out in house, which is what makes a replacement blade or impeller behave like the part it replaces: the same blade geometry, the same hub interface and the same balancing record are reproducible years after the original fan was built.
Blade moulding, hub machining, assembly and packing are handled under one roof, so a fan specification can be reviewed end to end before it is released for production.
 |  |  |
 |  |  |
The equipment that decides fan quality is the balancing and test equipment, because imbalance and airflow errors are what a customer feels in service.
 Dynamic Balancing Equipment |  Dynamic Balancing Equipment |  Dynamic Balancing Equipment |
 Cutting Machine Equipment |  Cutting Machine Equipment |  Wind Tunnel Laboratory |
The blade and reversible fan designs are protected by granted Chinese patents, and the company operates under ISO9001 and ISO14001 management systems. Certificate and report images are shown below; document copies and validity dates are available on request.
 Patent Certificate — Explosion-proof Fan Blade |  Patent Certificate — Variable Pitch Reversible Fan |  Patent Certificate — Adjustable Blade Angle Fan |
 ISO9001 |  ISO14001 |
Material behaviour is documented per batch: UV resistance and fire behaviour for PAG, explosion-proof type testing for conductive PAGAS, and certificate of analysis for the material and for the finished PAGAS blade.
 UV Resistance Report |  Explosion-proof Type Report |  PAG Material Fire Proof |
 Materials Certificate of Analysis |  PAGAS Blade COA |
Support covers the whole life of the fan rather than the shipment alone: duty review before ordering, fitting and replacement advice after delivery, and the documentation needed to keep an installation compliant.
Because blades, hubs and complete impellers are made in the same workshop, a spare part can be reproduced against the original blade count, hub family and pitch setting — the values that decide whether a replacement behaves like the fan it goes into.
Blades and hubs are packed so that the blade profile and the hub bore arrive undamaged, then crated or palletised for the transport mode agreed for the order.
 |  |  |
 |  |  |
A replacement is normally quoted from a few details rather than a drawing:
Diameter and blade count of the fan being replaced, plus the hub family if it is known
Connection holes and bushings — these are machined to match the existing hub so the part can be fitted
Working speed and duty point, so the pitch angle can be set before shipment
Environment: maximum air temperature and whether a conductive blade material is required
Documentation for material and test records (certificate of analysis, UV, fire and explosion-proof reports) where the project requires it
Where only the blades are worn, a blade set can be supplied against the existing hub instead of a complete impeller, and where the shaft interface has changed, the hub can be matched to the new drive. Technical questions are answered against the fan records so the answer stays valid for the whole machine fleet.
The questions below are answered for this product; the same support applies to its spare blades and hubs.
The K7Z covers 180 mm to 1254 mm with 3 to 16 blades, so one blade family can serve several fan sizes in the same machine program.
They share the K blade family and the Z-3 hub; the profile and the blade count are chosen against the duty point, with the K7Z used where the fan arrangement or duty point requires it.
PAG (-40 °C to 110 °C) and conductive PAGAS (-30 °C to 100 °C) where static discharge has to be avoided.
Yes. The pitch is set at assembly and recorded so a replacement reproduces the same airflow.
Yes. Connection holes and bushings are machined to the existing hub, and the set is balanced as an impeller before shipment.
Yes. Where the hub and shaft are serviceable, a blade set is supplied against the existing hub with the same blade count and material.
