Installing an ultrasonic meter within the commissioning valve module creates multiple benefits. These benefits include:
- Accurate flow rate measurement
- Commissioning using the subtraction method
- More accurate delta T measurement and monitoring
- More efficient ongoing commissioning
- MID approval to allow for billing
There are various types of energy meters available. Ultrasonic meters, however, have many benefits including:
- High flow measurement accuracy across a range of different and varying flow rates
- Unaffected measurement accuracy when particles of debris are present
- Unlikely to be damaged when debris is flushed through the system (hence no need to remove it during flushing)
- No moving parts, so accuracy is maintained throughout the life of the meter
With the introduction of an energy meter, there is no need for individual metering stations and flow straighteners in each terminal line, thereby mitigating the additional cost of the energy meter.
The flushing bypass assembly shown below, allows multiple functions to be performed. Using the processes outlined in the design guide the system can be fully vented, as well as forward and back flushed. Locating these valves all in one easy to reach location, decreases the time needed to fill, drain, vent and flush the system.
The assembly consists of two isolating valves, an air vent and drain port.
A large bodied strainer, as shown below, is assembled into the module. The strainer has a mesh size of 0.7mm. This is small enough to remove particles that might block control valves without creating excessive resistance. Due to the size of the strainer body, a large amount of debris can be collected before any reduction in flow is experienced. Locating the strainer within the valve module allows for easy access and, therefore, easier maintenance.
Isolation vValves (IVs)
An isolationng valve is a simple valve that provides flow rate shut off but which is not suited to flow regulation.
In a typical rigid system, each terminal branch would require its own isolation valve, each of these add two additional pipe joints. In a modular design, isolation valves can be incorporated within manifolds. This significantly reduces the individual cost of the valves and also reduces the number of joints required.
Double regulating valves (DRVs)
A double regulating valve is a regulating valve that can perform the double function of flow isolation and regulation. This is achieved by incorporating a locking mechanism in the handle of the regulating valve, allowing the valve to be regulated until the required flow rate is achieved, and then locked in place. If the valve is subsequently closed for isolation purposes, on re-opening, the valve handle will only open as far as its locked position.
Orifice plate flow measurement devices (OP)
An orifice plate (or fixed orifice) flow measurement device uses the pressure differential across an orifice as an indicator of flow rate. An orifice plate is a plate with a circular opening at its centre of a diameter that is less than the internal bore of the adjoining pipe. Pressure tappings are fitted upstream and downstream of the orifice and are used to measure the pressure differential signal across the orifice.
Flow rate can be determined from the equation
Q = 36 kv _P
Q = flow rate (l/s)
kv = device flow coefficient (provided by manufacturer)
DP = pressure differential signal across device
In rigid systems it would be common to install a flow measurement device on every terminal branch. In valve modules a single flow measurement device can be provided that enables the measurement of flows in all sub-branches.