# CWC – ROTAMETER

A rotameter is a device that measures the flow rate of fluid in a closed tube. It belongs to a class of meters called variable area meters, which measure flow rate by allowing the cross-sectional area the fluid travels through, to vary, causing a measurable effect.

Principle of Operation:

The rotameter’s operation 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 flow rate. With liquids, the float is raised by a combination of the buoyancy of the liquid and the velocity head of the fluid. The float moves up or down in the tube in proportion to the fluid flow rate and the annular area between the float and the tube wall. 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. A change in flow rate upsets this balance of forces. The float then moves up or down, changing the annular area until it again reaches a position where the forces are in equilibrium. To satisfy the force equation, the rotameter float assumes a distinct position for every constant flow rate. However, it is important to note that because the float position is gravity dependent, rotameters must be vertically oriented and mounted.

Materials of rotameter parts:

Connection mode of rotameter:

Technical Data:

 Model DN(mm) Range Accuracy °C MPa LPH CUM FM 15 15 10-100 ±4% 0-60 ≤1.0 20-200 50-500 200-1200 CWC 15 15 25-250 40-400 60-600 120-1200 CWC 25 25 100-1000 0.1-1.0 160-1600 0.16-1.6 250-2500 0.25-2.5 300-3000 0.3-3.0 CWC 32 32 400-4000 0.4-4.0 600-6000 0.6-6.0 CWC 40 40 600-6000 0.6-6.0 800-8000 0.8-8.0 1000-10000 1.0-10.0 CWC 50 50 1000-10000 1.0-10.0 1600-16000 1.6-16.0 CWC 65 65 5-25 8-40 12-60

Installation dimensions:

 Model L D L3 E L4 F G FM 15 100 40 145 ½” BSP 155 40 33 CWC 15 160 50 210 ½” BSP 230 56 27 CWC 25 170 59 225 ¾” BSP 275 71 28 CWC 32 225 72 290 1” BSP 345 86 35 CWC 40 225 78 320 1 ½” BSP 390 100 35 CWC 50 290 98 370 2” BSP 440 109 40 CWC 65 325 120 420 2 ½” BSP