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Hydrovar Functions
What does the Hydrovar do?
The main function the Hydrovar undertakes is to control the pump to meet system requirements in one of three ways:
 Diagram 1 Constant Pressure |
 Diagram 2 Constant Flow |
 Diagram 3 System Curve |
It performs this by:
- measuring the system pressure via a flow or pressure transducer on the pump discharge.
- calculates the motor speed to maintain the correct flow or pressure.
- send out a signal to the pump motor for it to start, increase speed, decrease speed or stop.
- in the case of multiple pump installations the Hydrovar will vary the order of the lead pump and turn the other pumps automatically on in the case of duty/assist sets.
In addition to the basic functions listed above, the Hydovar can also:
- Shut off the pump(s) as zero demand.
- Shut off the pump(s) if there is no liquid in the pump suction.
- Shut off a single pump at maximum flow or automatically switch an assist pump on.
- Protect the pump against over-Voltage, under-Voltage, motor overload and earth fault.
- Vary the ramp times for accelerating and decelerating the motor.
- Compensate for higher friction losses at higher flow rates.
- Send out a signal for remote monitoring of pressure and frequency.
- Start the pump for an automatic self-diagnostic test at set times.
- Keep a record of the length of time the pump(s) have run.
- Display all the functions on a L.C.D. in English, Italian, German, Spanish, Portugese and French.
Why is the Hydrovar different?
A typical construction of a pressure set includes one or more pumps assembled together with common suction and discharge manifolds which are connected to a large pressure accumulator, this packaged set is then connected to the system. As the system demands increase the pumps are switched on by some form of pressure sensor that operates through a control panel. On systems that require alternating duty sequencing a microprocessor is required and on some systems bypass lines are maintained by the use of metering valves. The use of some variable speed drives also requires the use of special motor/ controller combinations.
The Hydrovar does away with all of these.
What is a typical Hydrovar system?
As in standard booster sets the pumps are connected to common manifolds but require:
No special pumps or motors:
The Hydrovar will mount directly onto standard European design T.E.F.C. 3 phase motors up to 22 kW.
No separate pressure sensors:
The Hydrovar unit can work with any number of different sensor devices that provide a 4—20 mA signal, it is supplied as standard with pressure transducer or differential transducer, these are mounted on the pump discharge without the need for special pipework.
No separate microprocessor system:
In multiple pump systems normally a microprocessor is used to sequence the pumps or control the variable frequency on the pump motors. The Hydrovar is a microprocessor system so it does not need any further controllers.
No separate control panels and inverters:
A control panel has a number of in-built protections such as overload, temperature or short circuit; it also needs to have a way of controlling the pressure sensor and an inverter for variable speed applications. The Hydrovar acts as a control panel, we need as a bare minimum an isolated fused mains supply.
No bypass lines or metering valves:
Most control systems do not offer any protection against running the pump at zero flow or running off the designed performance curve. The Hydrovar will shut the pump off at zero demand or maximum flow (only one pump).
No large pressure accumulators:
If a constant speed pump is used without a pressure accumulator the pump would continually switch on and off with the motor operating at maximum power. By using the Hydrovar the pumps will ramp up and down from 0 to 2900 rpm to maintain a constant pressure or flow which eliminates the need for a large accumulator.
A small vessel is still required to maintain the pressure in the discharge line at zero demand. The Hydrovar requires vessels sized less than hall that of conventional systems, the use of the pump at the correct speed for the required duty means a significant reduction in energy consumption.
What does the Hydrovar include as standard?
The Hydrovar unit can be assembled onto any T.E.F.C. motor from 1.1 to 22 kW in size, it is recommended that metal fan cowls be used in order to affix the unit securely. The Hydrovar can be used on either vertical or horizontal pump models.
The Hydrovar units 1.1& 2.2 kW operates with a standard single-phase electrical supply but uses a three-phase motor. The Hydrovar units above this have a three-phase supply and motor.
The Hydrovar as standard comes with a pressure transducer, transducer cable, mounting devices for the Hydrovar, transducer and thermal sensor.
A standard transducer is supplied manufactured in 316 st. steel and designed to operate at pressures up to 10 bar, an alternative transducer is available on request for pressures up to 25 bar. An option of a differential pressure transducer supplied with an orifice plate used to maintain a constant flow is available.
The transducers are limited to an operating temperature range of 0 to 50°C, for higher temperatures t is necessary to use different mounting devices. Ambient air temperatures that the Hydrovar can be used in is between 5—35°C, humidity levels cannot exceed 50% at 40°C and 90% at 20°C. The unit is P54 as standard and should be protected from weather and condensation.
The environment should be free of excessive amounts of dust, acids, corrosive gases, salts etc.
The Hydrovar is fitted with an interference filter, complies with current European Directives relating to EMC and is 2000 compliant.
A L.C.D. display on the control panel shows all the information and programming help, languages available include English, Spanish, German and Italian.
Pressure sensitive switches allow the operator to increase, decrease and select commands.
Power display lamps show the current status of the Hydrovar.
For more information, contact Les Cotton Pumps Ltd:
| Email: | |
| International | U.K. Local Rate |
|---|---|
| Tel: +44 1395 519664 | Tel: 0845 458 2892 |
| FAX: +44 1395 516261 | Tel: 0845 458 2903 |
| Mail: Les Cotton Pumps Ltd., 5 Bennetts Hill, Sidmouth, Devon, EX10 9XH, U.K. | |