Product details
Weiss Bimetal Thermowell | BN9-75BS | 9″ Length | Brass | 2.5″ Lagging Extension
Product Description
The BN9-75BS is the specialized socket for 9-inch (225 mm) stem bimetal thermometers. The “BN” designation identifies this as a Bimetal Thermowell featuring a Stepped Stem design and a Lagging Extension.
In the UAE’s HVAC and district cooling sectors, pipes are often heavily insulated to prevent energy loss and condensation. The BN9-75BS is designed to overcome this; it features a 2.5-inch (64 mm) lagging extension (T-dimension) that allows the thermometer dial to clear the insulation, combined with a 6.5-inch (165 mm) insertion depth (U-dimension) to ensure the sensing element is positioned deep within the fluid stream. The stepped-stem design reduces the diameter at the tip to minimize thermal mass and ensure a rapid, accurate response.
Key Features
- 5″ Lagging Extension: Specifically designed to extend through thick pipe lagging, ensuring the thermometer dial is visible and accessible for maintenance.
- Stepped Stem for Rapid Response: The reduced diameter at the sensing end allows the bimetal element to react quickly to temperature changes in the system.
- Premium Brass Construction: Offers superior thermal conductivity and excellent corrosion resistance in non-aggressive fluids like chilled and hot water.
- Standard 3/4″ NPT Process Connection: The universal mounting size for mechanical piping, ensuring easy installation into standard pipe tees and fittings.
- 1/2″ NPT Instrument Thread: Precision-threaded to accept standard bimetal thermometers with a 1/2″ NPT fixed connection.
Technical Specifications
| Specification | Details |
| Brand | Weiss Instruments |
| Model | BN9-75BS |
| Nominal Stem Length | 9″ (225 mm) |
| Insertion Length (U) | 6.5″ (165 mm) |
| Lagging Extension (T) | 2.5″ (64 mm) |
| Material | Brass |
| Stem Design | Stepped Shank |
| Process Connection | 3/4″ NPT |
| Instrument Connection | 1/2″ NPT (Standard for Bimetal) |
| Application | Insulated Piping / Bimetal Dial Thermometers |
Frequently Asked Questions
- Q: Which thermometer fits the BN9-75BS?
- A: It is designed for bimetal thermometers with a 9-inch stem, such as the Weiss 3BBM9 or 5BBM9 series.
- Q: Why use a 9″ stem well instead of a 6″ stem well?
- A: The 9″ version is used for larger pipe diameters (typically 10″ and above) to ensure the sensing tip reaches the middle of the fluid flow, or when very thick insulation (over 2 inches) is present.
- Q: Is this suitable for potable water?
- A: For drinking water systems in the UAE, you should verify if the project specifications require the Lead-Free (LF) version (BN9-75BSLF).
