KEP ES-749 Application Note

Steam Metering Concepts

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Vortex

Flowmeter

Typical Steam Metering System

Using Vortex Flowmeter and Electronic Flow Computer

This document was created to aid in the explanation of the measurement of steam by a vortex steam
owmeter system and the related service operations.

General

A typical steam-metering system typically consists of several components:

• Vortex Flow Meter installed in the saturated steam line

• A static pressure transmitter to measure steam pressure

• A Flow Computer to compute the steam ow

• A Data Logger/Modem to monitor the customer site and provide trend information

NOTE: If remote metering is supported, a remote PC, modem, and remote metering software may be used

in conjunction with this system.

HELP TIP: The piping surrounding the location where the owmeter and related transmitters are installed is

called the “meter run”.

Tech Note#F049 06/10/10

KESSLER-ELLIS PRODUCTS 10 Industrial Way East, Eatontown, NJ 07724

800-631-2165 • 732-935-1320 • Fax [phone] • http://www.kep.com

Equipment Selection

The owmeter is sized by the manufacturer, based on the expected line conditions and ow rate anticipated
in the application. This normally requires that the line size, steam pressure range and expected steam ow
rate range be known. The vortex owmeter is selected for steam service with a measurement range that
will meet or exceed the maximim owrate. The static pressure transmitter is selected for steam service with
a measurement range that will meet or exceed the range of static line pressure to be encountered in the
application. The ow computer performs the necessary calculations needed to compute the steam ow from
the electrical signals being fed into it. The datalogger and modem permit remote monitoring of the information
fed into the data logger. The information is sent to the datalogger by either the input measurement or the
computed outputs from the ow computer. A remote PC with modem can access the information either in the
data logger or in the current readings of the ow computer.

Factory Calibration

The ow meter, transmitters, ow computer, and data logger 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 owmeter and static pressure transmitters 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 normally involves double-checking of each transmitter range and optional features
using a hand held terminal.

The ow computer is setup by entering the information on the owmeter and static pressure transmitter. In
addition, the items to be included in the data logger are also setup. This is usually done from the front keypad,
although connecting the device to a laptop and using a special program supplied by the manufacturer can
also be used. Setup may also be accomplished remotely via the modem connection.

The setup of each individual item is veried. 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 ow computer input channel. If a change is made to one, it must be made to all.

The basic operation of the system can be veried by checking that the respective sensors are producing
the correct signals, based on the observed signal, the ow range setup in the sender and receiver of the
information, and the observed process conditions in the steam line. Signal simulators and multi-meters may
also be used.

There is a “low ow cutoff” that should be set to prevent the system from metering when no ow is present.
This also limits the low ow measurement range, so it is usually set to the lowest practical value.

Meter Readings

Meters may be read either locally by taking a reading from the ow computer, or remotely by taking a reading
from the ow computer via modem, or by reading the data logger. The operational status of the metering
system is also checked periodically.

KESSLER-ELLIS PRODUCTS 10 Industrial Way East, Eatontown, NJ 07724

800-631-2165 • 732-935-1320 • Fax [phone] • http://www.kep.com

Servicing the Metering System

Often a utility will perform various inspections each year on each steam meter. Manufacturers of the
components used in a steam 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 ow computer, and data logger usually have some diagnostic
capability and can assist in problem detection and notication.

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

If a transmitter is changed by either replacement, re-scaling, or re-spanning then the new scaling of that
transmitter must also be set into corresponding ow 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 ow
computer and data logger 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.
Inputting known pressure using a special hydrostatic pressure pump may check many pressure transmitters.
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 Steam Metering applications. It is
available in a variety of housings to suit a wide range of application environments.

SUPERtrol II

• “EZ Setup”- Guided Setup for First Time Users

• Liquid, Gas, Steam and Heat Flow Equations

• Utility Metering

• Menu Selectable Hardware & Software
Features

• Internal Data Logging Option

• Isolated Pulse and Analog Outputs Standard

• RS-232 Port Standard, RS-485 Optional

Windows™ Setup Software

• NX19 Gas Equations, Stacked DP Transmitters

KESSLER-ELLIS PRODUCTS 10 Industrial Way East, Eatontown, NJ 07724

800-631-2165 • 732-935-1320 • Fax [phone] • http://www.kep.com

• DDE Server & HMI Software Available

• Remote Metering by Wireless or Modem

• NEW! - Attractive Wall Mount Enclosure