Sight Flow Indicators

TB Series-C / HT Series-B Flow Sight Glass Gauge

Double-window colour-ball indication — TB-C and high-pressure HT-B

Observe compatible gas and liquid flow through two windows using PTFE colour balls. TB-C uses tempered glass; HT-B uses borosilicate glass for the high-pressure model.

IECEx / ATEXOptional certification: II 2G, Ex h IIC Tx Gb

TB-C Type

HT-B Type

Service and indication

Compatible gas and liquid service for water treatment and industrial flow systems
Double-window observation with PTFE colour-ball indication
Horizontal flow in either direction or vertically upward

Technical data

Operating limits and connections

Teflon gasket: −40 to 150°C
Sigma 533 gasket: −40 to 180°C
TB-C maximum pressure: 16 kg/cm² at 25°C water
HT-B maximum pressure: 100 kg/cm² at 25°C water, without Ex certification
Ex application pressure: 0–16 kg/cm² gauge
TB-C connection sizes: ½ inch (15A), ¾ inch (20A)
HT-B connection sizes: ½ inch (15A), ¾ inch (20A), 1 inch (25A)
Female threads: NPT, PF (BSPP) or PT

Materials

Body / wetted parts: SS316 (CF8M)
Colour balls: PTFE
TB-C window: Tempered glass
HT-B window: Borosilicate glass
Gaskets: Teflon or Sigma 533

Dimensions and mounting

Dimensions in millimetres.

TB-C front and side drawings with L and H dimensions — **TB-C**

Leftward, rightward and vertically upward flow mounting diagrams — **Permitted mounting positions**Horizontal flow in either direction or vertically upward.

TB-C Type
Dimension	½ inch (15A)	¾ inch (20A)
L	114	114
H	72	72

HT-B front and side drawings with L and H dimensions — HT-B

HT-B Type
Dimension	½ inch (15A)	¾ inch (20A)	1 inch (25A)
L	83	83	83
H	100	100	100

Explosion-proof certification and temperature classes

Optional IECEx and ATEX II 2G certification, Ex h IIC Tx Gb. The class is selected for the process and ambient temperature.

Temperature classes for the offered 15A–25A sizes
Code	Process and ambient conditions
T2	175°C < Tprocess ≤ 270°C; Tamb ≤ 75°C
T3	110°C < Tprocess ≤ 175°C; Tamb ≤ 75°C
T4	75°C < Tprocess ≤ 110°C; Tamb ≤ 75°C
T5	60°C < Tprocess; Tamb ≤ 75°C
T6	Tprocess and Tamb ≤ 60°C

Ex applications are limited to 0–16 kg/cm² gauge, including HT-B.

These are certification-class conditions, not higher gasket ratings. Teflon is limited to 150°C and Sigma 533 to 180°C. Confirm any class/application combination against these material limits.

The source gives T5 a lower process-temperature bound only. It also lists conditions for sizes 80A and above; those sizes are not offered in this ordering table.

Ordering information

Choose your model and options to build an enquiry reference.

1. Series

2. Wetted parts

3. Connection size

4. Female connection thread

5. Gasket

6. Explosion-proof certification

7. Temperature classification

8. Maximum working pressure

Selected referenceChoose one option from each field

Request a quote

Select all options to request a quote.

Pressure ratings are at 25°C water. Confirm suitability for the actual process and temperature.

Specifications are general selection guidance. Confirm materials, connection standards, operating temperature and pressure with Sightflow before placing an order.