The flow-captor and vent-captor are compact, self-contained flow sensors that work according to a calorimetric principle. The principle allows for the creation of compact, reliable flow sensors with a price/performance ratio not possible with other physical flow-sensing principles. Especially at a low flow rate, no other sensing principle can achieve the high accuracy as the flow-captor. First engineered by weber Sensors more than 20 years ago, weber continues to pioneer sensors based on this principle.
flow-captor and vent-captor are available as insertion and in-line types. Both are also available with a binary output as switches and adjustable set-point and with an analog output as meters with an adjustable measuring range.
A series of flow-captors and vent-captors offer temperature measuring features.

The Calorimetric Principle
The calorimetric principle is sometimes called the heat dissipation or simple thermal principle. Basically, a small probe that is exposed to the medium to be sensed is electrically heated above the medium temperature. The flow of the medium creates a cooling effect that cools the probe more or less relative to the velocity. The temperature change is measured and converted into the desired electrical output signal.

Please e-mail us for detailed information about the calorimetric principle.

Monitors, Meters
flow-captor and vent-captor are available as monitors and meters. Because of the principle of calorimetrics, the flow-captor and vent-captor are the most reliable and dependable flow monitors on the market. flow-captor and vent-captor as meters break the barrier of the accuracy-trumpet and are unparalleled when it comes to the measurement of low flow.

Calorimetric flow sensors are characteristically very sensitive at a very low flow rate but stop working properly at a higher flow rate, normally at a flow rate of approximately 50 cm/s (water) and 10 m/s (air). flow-captor and vent-captor use advanced calorimetric principles that enable it to extend the almost linear flow rate up to 4 m/s (flow-captor) and up to 30 m/s (vent-captor).

Because of this unique feature, flow-captor and vent-captor are available as accurate flow meters with wide measuring range as well as flow switches with wide linear set-point range. For the same reason, flow-captor and vent-captor can be calibrated for a wide vairety of emdia. Our standard products are calibrated for water, oil or air because these media are used in most applications. If an accurate set-point is required with other media, the flow-captor and vent-captor can be calibrated to meet your specifications.

Insertion Types
The Insertion type flow-captor are applicable beginning with 1/2" pipe up to the maximum pipe diameter available, the vent-captor are beginning with 1" pipe. The insertion depth is 1/7" of the pipe diameter or 1 1/2" maximum in most cases, based on requirements. Because of this, the flow-captor and vent-captor don't obstruct the flow or cause pressure to drop.

Inline Types
The sensor elements of the inline flow-captor are integrated with the outside of the pipe. They are non-intrusive; the pipe inside the sensor is smooth.

Remote Systems
Most flow-captors and vent-captors are available as compact units or as remote sensors with separate electronic units. The remote systems are useful for applications where mechanical space limits access or the medium temperature conditions are extreme, requiring physical protection.

Flow Monitor, Binary Output
A very important application for flow sensors is the monitoring of cretical flow, like cooling water in a nuclear power plant, welding robots, etc. It is especially useful in applications where the flow sensor acts as a kind of security device, giving an alarm when something goes wrong. These sensors are needed because there is always a risk something will go wrong. You don't want to wait until something fails to say,
"I wish I had one."

For many applications, flow monitors are required by law or specific regulations. To meet the requirements, many OEMs install less expensive devices. It may work fine, until -- usually after the warranty period is over -- something fails.

Preferred devices in this application are what's often called "paddle switches." A paddle switch is a kind of paddle attached to an axle and connected to a micro switch. The flow moves up the paddle resulting in an "on" signal and is supposed to move back down when the flow stops. Normally, it works for only a short period of time.

Problems are caused by sediments in the medium or by corrosion -- causing the axle to stick and fail to turn. So if the flow stops, it fails to give the warning signal. The failure is only noted during the now "emergency" situation, when it's too late.

flow-captor and vent-captor have no moving parts and are not affected by ware and tare. flow-captor and vent-captor are the most reliable flow monitors available and are the best protection devices for all equipment where flow of any media is crucial. See applications examples.