Wednesday, May 31, 2017

Heated or Chilled Water Concepts in Campus Metering Applications

Reprinted with permission from KEP

Typical Heated/Chilled Water Metering System Using Magnetic Flowmeter System, Two Temperature Transmitters and Electronic Flow Computer.

A typical modern, heated/chilled water metering system usually consists of several components:
  • Flow Meter installed in the line
  • A temperature transmitter mounted in the supply line to measure the supply temperature 
  • A temperature transmitter to measure return temperature 
  • A Flow Computer that will compute the energy flow 
  • An optional Data Logger/Modem that will monitor the customer site and provide trend information 
If remote metering is required, a remote PC, modem, and remote metering software may be used in conjunction with this.
Typical Heated/Chilled Water Metering System
Typical Heated/Chilled Water
Metering System with Flow Computer

Equipment Selection

The flowmeter is sized by the manufacturer based on the expected line size, fluid and flow rates anticipated in the application. This would normally require the line size, flow rate range and expected line conditions of temperature and pressure be known. The temperature transmitters are selected for a measurement range that will meet or exceed the range of temperature to be encountered in the application. The flow computer performs the necessary calculations needed to compute the energy flow (BTU’s or ton-hours) from the electrical signals being fed into it. The optional data logger and modem permit the remote monitoring of those signals and the data logging of the measured and computed values. A remote PC with modem can access the information either in the data logger or in the current readings of the flow computer.

Factory Calibration

The flow meter, flowmeter, the transmitters and the flow computer are calibrated by their respective manufacturer’s prior to being supplied to a utility company in accordance with the instructions provided when the units are purchased.

Installation

During installation the two temperature transmitters and the flow computer are installed in accordance with industry guidelines and manufacturers instructions.

The individual calibration and setup documents provided by the manufacturers are reviewed.

Startup

During startup the individual components of the systems are setup so that they operate correctly.

For the transmitters this will normally involve double-checking of each transmitter range and optional features using a hand held terminal.

The flow computer will be setup by entering the information on the flowmeter, and with the ranges of both temperature transmitters. In addition, the desired items to be included in the data logger will also be setup. This is usually done by the front keypad although connecting the device to a laptop and using an external, special program supplied by the manufacturer could also be used.

The setup of each individual input item is verified. For each measurement, there is a transmitter to scale and send an electrical signal to the receivers that need this information. The scaling of each transmitter must also be set into the corresponding flow computer input channel. If a change is made to one, it must be made to all.

The basic operation of the system can be verified by checking that the respective sensors are producing the correct signals, based on the observed signal, the flow range setup in the sender and receiver of the informa- tion, and the observed process conditions in the line. Signal simulators and multi meters may also be used.

When using voltage or current ranges for the flow input, there is a “low flow cutoff” that should be set to prevent the system from metering when no flow is present. This is also limits the low flow measurement range so it is usually set to the lowest practical value.

There is also a low temperature cutoff that can be used to prevent the false totalization of energy when small differential temperatures are indicated while recirculating water.

Meter Readings

Meters may be read either locally by taking a reading off the flow computer or remotely by taking a reading off the flow computer by modem or by reading the data logger or both. The operational status of the meter system is also checked periodically.

Servicing the Metering System

Often a utility will perform various inspections each year on each energy meter. Manufacturers of the compo- nents used in the system provide a number of service and test aids for Service personnel that permit them to interrogate a component to determine if it is operating properly. From time to time problems may occur in any system. The transmitters, flow computer, and data logger usually have some diagnostic capability and can assist in problem detection and notification.

If it becomes necessary, for any reason, the flowmeter may be changed out. This sometimes occurs when the heating load changes or the actual flow range is different than the expected range as a result of inaccu- rate sizing information. When a sensor change out occurs the information on the new flowmeter must also be set into corresponding transmitter and the flow computer flow input channel. If a change is made to one, the change must be made to all.

If a transmitter is changed by either replacement or re-scaling or re-spanning then the new scaling of that transmitter must also be set into corresponding flow computer input channel. If a change is made to one, the change must be made to all.

Most utilities remove portions of the meter system from service after several years for recalibration. The flow computer can usually be checked in place using simulators. They can be removed from service if needed and replaced with another device that then must be setup for use as described earlier. In other cases, the transmitters are replaced with a calibrated replacement unit.

KEP Flow Computer
Kessler-Ellis Products (KEP) offers the Supertrol 2 Flow Computer for Heated or Chilled Water Metering applications. It is available in a variety of housings to suite a wide range of application environments.

For more information on KEP products follow this Flow-Tech link or call 410-666-3200 in Maryland, or 804-752-3450 in Virginia.

Wednesday, May 24, 2017

Drager X-Zone 5500 Hazardous Gas Area Monitoring

Drager X-zone 5500
Drager X-zone 5500
The Dräger X-zone 5500 transforms the Dräger X-am 5000/5100/5600 personal gas detection instruments into innovative area gas monitoring devices for a wide range of applications. In addition to personal air monitors carried on the body, these area gas monitors are positioned where gas hazards are expected to increase the level of safety.

Wireless fenceline

Up to 25 Dräger X-Zone 5500 can be automatically interconnected to form a wireless fenceline. The interconnection of the area monitoring devices allows for rapid establishment of safety networks for larger areas. A Dräger X-zone 5500 detecting a gas alarm transmits the alarm signal to all interconnected units. A red flashing master alarm in the mother unit detecting gas contrasts with red/green flashing alarms of the connected daughter units providing simple recognition of alarm status and the actual location of the hazard.

With the corresponding configuration, the maximum gas concentration in the monitored area is shown on the display. Combined with the display of the X-zone ID a clear containment of the hazard area is possible.

Clear warning

The illuminated green LED ring indicates that the air is free of toxic and combustible gases. Upon detection of gas hazards, the LED color changes from green to red, thus providing a clear visual warning that gas is present. Additionally, a loud and highly audible evacuation alarm is emitted. The Dräger X-zone 5500 gas entry is arranged that the gas can diffuse into Dräger X-am gas monitors from all sides.

Perfect for confined spaces

An integrated pump version allows for continuous monitoring of confined spaces and locations which are difficult to access, even from a distance of up to 150 ft.

Other benefits
  • Visual 360° LED (illuminated ring) 
  • Audible 360°; > 108 dB in a distance of 1 m (30 ft.), 120 dB in a distance of 30 cm (1 ft.) 
  • Approval for Ex-Zone 0 
  • Daily function test and calibration not required after single on-site testing 
  • Individually configurable with the Dräger CC-Vision PC software (eg. alarm frequency) 
  • Inductive charging station: easy and convenient non-contact charging 
  • Continuous operation for up to 120 hours: The 24 Ah battery of the Dräger X-zone 5500 provides up to 120 hours of continuous operation – a complete working week.

Saturday, May 13, 2017

Basics of Variable Area Flowmeters

Variable area flowmeters (rotameters) are engineered to provide years of repeatable, reliable measurement of gas and liquid flow rates.

Features

  • Reliable, easy-to-read displays
  • Fail-safe flow indication under any circumstance
  • Integral flow controller to compensate for varying pressures
  • Materials and designs to suit multiple pressure ranges
  • Field-replaceable components and custom scales
  • Integration of optional flow switches, automated valves or alarms

Applications

  • Basic liquid or gas flow measurement
  • Rotating equipment flow measurement
  • Process analyzers
  • High-pressure flow on offshore oil platforms
  • Chemical injection
  • Purge liquid or gas metering

Watch the video below for a full understanding of variable area flowmeters. For more information, contact Flow-Tech in Maryland at 410-666-3200 or in Virginia at 804-752-3450.

Sunday, May 7, 2017

FCI ST100 and ST110 Thermal Dispersion Flow Meters

FCI flow meters
FCI flow meters
FCI flow meters operate on the principle of thermal dispersion. The flow meter circuitry measures the temperature differential between a heated and a non-heated sensors.  The greater the mass flow rate, the less temperature differential between the two sensors.

FCI flow meters
FCI ST100
The ST100 series transmitter is unsurpassed in meeting your current and future need for outputs, process information and communications. Whether your output needs are traditional 4-20 mA analog, frequency/pulse, alarm relays or advanced digital bus communications such as HART, FOUNDATION Fieldbus, PROFIBUS, or Modbus, ST100 has you covered. ST100's bus communications have been certified by and are registered devices with HART and Foundation Fieldbus. In addition, Emerson Process (Delta V), Yokogawa and ABB (800xA) have tested and verified ST100 Series' FOUNDATION Fieldbus interoperability with their systems. Should you ever need to change or upgrade, ST100 can be converted to any of these outputs with a simple card change in the field.

FCI flow meters
FCI ST110
Many alternative flow meters require periodic removal from service verify calibration which can be expensive if the flow meter needs to be sent back to the factory. The FCI ST110 is capable of calibration verification without being taken out of service.

ST100 flow meters offer the following advantages over other gas flow technologies:
  • Three, 4-20 mA outputs for flow, temperature, and/or optional pressure
  • Very high turn down ratios - up to 1000:1
  • Digital communication options of Foundation Fieldbus, PROFIBUS,  HART or Modbus 
  • The data logging via removable SD card
Ruggedness, accuracy, and superior quality made FCI the leader in thermal dispersion mass flow meters, flow switches and level switches for industrial process measurement applications. FCI air and gas flow meters are applied from small dosing lines to the largest stacks. For more information about FCI in Maryland or Virginia, visit http://www.flowtechonline.com or call 410-666-3200.