ALLWEILER NBT Series Volute Thermal Centrifugal Pump

ALLWEILER NBT Series Volute Centrifugal Pumps | Direct-Connected Circulation Solutions for Heat Transfer Oils and

High-Temperature Heat Media

ALLWEILER NBT Series Volute Thermal Centrifugal Pump Product Overview

The NBT series is a direct-connected volute centrifugal pump designed by ALLWEILER, a German company, specifically 

for the circulation of organic heat transfer oils and high-temperature heat media. It features a block design and meets 

DIN EN 733 standards. This series is one of the mainstay models in ALLWEILER's heat media pump product line, with

 extensive application cases and an excellent reputation in the field of heat transfer oil circulation—some installations 

have operated without failure for over 20 years.

ALLWEILER, a German pump brand with over 160 years of history (now part of the CIRCOR Group), has accumulated 

profound technical expertise in the field of high-temperature heat media pumps. The NBT series differs structurally from 

the NTT series (base-mounted) and NTWH series (flow-type design). It employs a direct-drive, block-type structure, with 

the motor directly connected to the pump body via a flange or lantern bracket. This eliminates the need for couplings and

 a common base, resulting in a smaller installation space and lighter weight, making it particularly suitable for applications 

where installation space and cost are critical.

Series Positioning Comparison:

NBT Series: Direct-drive block design, for heat transfer oil only, up to 350°C, DN EN 733 standard

NTT Series: Base-mounted, for heat transfer oil only, up to 350°C, DN EN 733 standard

NTWH Series: Base-mounted, wide temperature range for heat transfer oil/synthetic oil/high-temperature hot water, up to 400°C

ALLWEILER NBT Series Volute Thermal Centrifugal Pump Core Technical Parameters

Parameter Item | Specification Range

Maximum Flow Rate | 270 m³/h

Maximum Head | 145 m (two-stage pump version)

Maximum Outlet Pressure | 16 bar (PN 10)

Maximum Medium Temperature | 350 °C

Speed | 2900 rpm / 1450 rpm (optional)

Connection Method | Flange connection (DIN standard)

Installation Method | Horizontal, direct-drive block design (motor connected via flange/lantern frame)

Design Standard | DIN EN 733 (formerly DIN 24255)

Applicable Media Organic heat transfer oil (thermal oil)

Electric motor (IEC standard motor)

ALLWEILER NBT Series Volute Thermal Centrifugal Pump  Product Features and Design Advantages

1. Direct-Connect Block Design, Compact Structure

The NBT series adopts a direct-connect block design, where the motor connects directly to the pump body via a flange 

or lantern frame, eliminating the need for couplings and a common base. This design offers several advantages: small 

footprint, significantly saving installation space; lightweight, easy to handle and install; lower cost than base-mounted

 installation solutions; and the option for horizontal or vertical installation, flexibly adapting to different site layouts.

2. Superior High-Temperature Resistance

Designed specifically for organic heat transfer oils, it can withstand media temperatures up to 350°C. The mechanical 

seal is located behind the thermal barrier, effectively protecting the seals from high-temperature damage and extending seal life.

3. Compliant with DIN EN 733 Standards

The housing dimensions and rated output strictly comply with DIN EN 733 standards, ensuring good interchangeability 

with mainstream pump models on the market.

4. Optional Two-Stage Pump Design

Within the same overall dimensions, the two-stage pump version offers a higher head, up to 145 m, particularly suitable

 for applications requiring low flow rates and high head.

5. Proven High-Temperature Application Performance

The NBT series has received positive market feedback in high-temperature applications. For example, Ipsen International 

GmbH, a leading global manufacturer of high-temperature furnaces, has been using NBT series pumps in its quenching oil 

circulation systems since 1993, achieving over 20 years of trouble-free operation with no wear repairs or customer complaints.

 Furthermore, the NBT series pumps are designed to exceed the safety requirements of DIN 4754 hot oil systems, featuring 

additional safety elements to prevent large-scale liquid leakage in the event of mechanical seal failure.

6. Flexible Configuration Options

Supports various installation configurations to meet different site requirements: split configuration (motor and pump body 

independent, base-mounted), direct-coupled block version (horizontal or vertical installation), and direct-coupled pipeline 

version (vertical or horizontal installation). In addition, all pumps use IEC standard motors.

ALLWEILER NBT Series Volute Thermal Centrifugal Pump Core Application Areas

NBT series thermal oil pumps are widely used in the following industries and scenarios:

Application Areas Typical Scenarios

Heat Transfer Technology: Thermal oil boilers, heat medium circulation systems, community heating

Petrochemical Industry: Hydrocarbon preparation, reactor heating

Chemical Industry: Chemical preparation, hot fluid transportation

Rubber Industry: Vulcanizing machine heat medium circulation

Food Industry: Frying equipment, drying equipment hot oil circulation

Road Construction/Asphalt: Asphalt heating and insulation, storage tank circulation

Wood Industry: Drying kiln hot oil circulation

Shipbuilding/Marine Engineering: Marine hot oil systems

Heat Treatment Quenching Systems: Quenching oil circulation (e.g., Ipsen high-temperature furnace applications)

Applicable Media: Organic heat transfer oils (thermal oils)

Common Model Reference

The following are some common NBT series models (partial list):

ALLWEILER NBT Series Volute Thermal Centrifugal Pump Model | Specifications

NBT32-160 / 02U5A-W4-38/300 | Small diameter, 160 impeller

NBT32-160U5A-W4 | Standard configuration

NBT32-160/167U5A-W4-38/300 | Customized configuration

NBT32-160U5A-W4-28/250 | Customized configuration

NBT32-200/205 | 200 impeller series

NBT40-160 | 40 diameter series

NBT2/32-200/205U5A-W4-42/350 | Two-stage pump version

Model Explanation: The "NBT2/" prefix in the model (e.g., NBT2/32-200) indicates a two-stage pump structure, 

meeting higher head requirements.

Installation and Maintenance Guide

Installation Precautions

Installation Location: Primarily horizontal installation, but vertical installation can also be chosen depending on site conditions.

Pipe Connections: Inlet and outlet pipes should be independently supported to prevent the weight of the pipes from acting

 on the pump body flanges.

Pipe Cleaning: Thoroughly clean the inside of the pipes before installation to prevent impurities from entering the pump body.

Thermal Expansion: Under high-temperature conditions, it is recommended to install expansion joints at the inlet and outlet to 

absorb thermal expansion.

Maintenance Recommendations

Regular Seal Inspection: Observe the mechanical seal for any signs of leakage.

Thermal Barrier Protection: The mechanical seal is located behind the thermal barrier; check the thermal barrier status during

 maintenance.

Standby Pump Management: The standby pump should be periodically cranked to prevent jamming.

Safety Design

The NBT series pumps are designed to exceed the safety requirements of DIN 4754 for hot oil systems. In the event of mechanical

 seal failure, additional safety elements ensure that only a small amount of liquid leaks, which can be collected and diverted without 

causing damage. The special design of the insert unit reduces temperature, helping to extend the life of bearings and shaft seals.

Product Advantages Summary

Advantages Explanation

✅ German Quality: 160+ years of pump industry technology accumulation, a brand under the CIRCOR Group

✅ Direct-drive compact design: Saves installation space, no need for couplings or common bases

✅ Ultra-high temperature resistance: Can withstand up to 350°C for heat transfer oil

✅ Compliant with DIN EN 733 standard design, excellent interchangeability

✅ Two-stage pump option: Maximum head up to 145m, meeting high head, low flow rate requirements

✅ Mature track record: 20+ years of trouble-free operation in high-temperature furnace quenching oil systems

✅ Safety design: Exceeds DIN 4754 standards, with additional protection in case of seal failure

✅ Flexible installation: Horizontal/vertical options available, adaptable to different site conditions

✅ IEC standard motor: Convenient parts procurement