Miniature Glass Variable Area Flowmeter – MGT30


isolvThe flow meter operates is based on the variable area principle: fluid flow raises a float in a tapered tube, increasing the area for passage of the fluid. The greater the flow, the higher the float is raised. The height of the float is directly proportional to the flowrate.

The float reaches a stable position in the tube when the upward force exerted by the flowing fluid equals the downward gravitational force exerted by the weight of the float. The float then moves up or down, changing the annular area until it again reaches a position where the forces are in equilibrium.

A change in flowrate upsets this balance of forces. The float adjusts itself so that the buoyancy force B acting on it, wall tube resistance W and its downward gravitational force by weight of the float G are in equilibrium: G = B + W

It is important to note that because the float position is gravity dependent, flowmeter must be vertically oriented and mounted.

• Glass measuring tube with plastic cover
• Standard with needle valve assembly
• Different material available for process connection e.g Stainless steel, PVC
• Process Temperature: - 5°C to 120°C
• Operating pressure up to 10 bar
• Can be assembled with differential pressure regulator to ensure constant flow in fluctuating
operating pressure

Designed for flowrate measurements in many of industry including, food industry, water treatment plants and the chemical industry.

Technical Details
Turn-down Ratio
10 : 1
Accuracy Class to VDI/VDE
Code 3513, Sh.
Measuring Cone
Length in mm (inches): 100 (3.94”)
Scale graduation: Flow units
Operating Data
Max. allowable operating pressure at 20 °C (68 °F). Test pressure is 1.3 times the specified max. allowable operating pressure.*
6 bar
Max. Process Temperature
120 °C (212 °F)
With Limit Switches
80 °C (176 °F)
* At temperatures > 20 °C (68 °F) pressure drops at the rate of 1% per degree C
** Flow > 2400 l/h, air: 4 bar
Overall Height and
Connection Dimensions
Refer to the catalogue
Standard 1/4”NPT, G1/4
Measuring Cone
Borosilicate glass
Float Standard

Stainless steel 1.4401 (316) /

PTFE (Option)
Float Stop
Stainless steel 1.4571 (316 Ti)
Top/bottom connection block:
stainless steel 1.4581 (318 C17)
stainless steel 1.4571 (316 Ti)
Note: Specification are subject to change without notice.

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