Homework SourseGenerate a flow table for a circuit that when presented with
Solution
The steam flow meter is designed only to measure the saturated steam flow rate. The meter uses the pressure difference output from anelliptical tube, a throttle unique to Azbil Corporation. In addition,the meter measures in-pipe pressure to find the density of saturated steam in the piping.Using the differential output and density, the meter calculates and outputs the mass flow rate.
Design
The MVC30A/31A (of an integral type) of the steam flow meter is designed as shown below:
Integral structure
The MVC30A/31A of the steam flow
meter consists of the following:
A detection end, which detects steam flow pressure difference.•
A converter, which converts the detected pressure difference into an output signal.
Parts
Design and Functions
Azbil Corporation
1-2
Model: MVC30/31 - Steam Flow Meter \"STEAMcube\"
Integral structure
The MVC30A/31A of the steam flow
meter consists of the following:
•
A detection end, which detects st
eam flow pressure difference.
•
A converter, which converts the detected pr
essure difference into an output signal.
1-2-1:
Parts
Table 1-1 Parts
Converter
Name
Descriptions
Main converter unit Main MVC30A/31A unit. The unit converts a pressure difference signal to electrical signals for the flow rate, pressure, and temperature and outputs them.
Meter cover
Converter LCD display cover. The display has a glass readout panel.
Converter cover
Converter terminal block cover Meter body Converter terminal receiver Converter cover flangeThese flanges sandwich the meter body to form a pressure container.
Electrical conduit
A power and analog output cable, a pulse output cable, and a ground cable run out through this conduit.
Cable gland
A plastic cable gland is used for a waterproof type. On the other hand, a cable gland is used for
an explosion-proof type. The wires to be used are 9 to 12 mm in diameter.
Nameplate
The nameplate is marked with the information given
below. A meter of an explosion-proof type only has a
Setting range
Date of production
Measured steam pressure Power supply and pulse weight (underlined) Output Ambient temperature Maximum load Explosion-proof No.
Bracket
Bracket for attaching the converter to a 2-inch pipe (vertical/horizontal)
Detection end unit
Elliptical tube type detection end Elliptical tube detection end, or a throttle unique to Azbil Corporation. The throttle, which has a shape like a velocity profile, reduces pressure losses, thus providing a stable pressure difference.
The throttle diameter ratio is
= 0.4.
Pipingconnection
This surface comes in contact with a pipe. shows the appearance of a steam flow meter,which is of a wafer type. Steam flow meters of a flange type are also available. Select either of the types as necessary.Pressure outlet Pressure outlet for detecting pressure difference generated at the elliptical tube steam, or a fluid to be measured, flows from left to right. An arrow marked on the detection end,indicates the direction of flow. Check the arrow. The primary pressure outlet, which is at the left of the figure,is called the HP side, and the secondary pressure outlet, is called the LP side.
Self water seal
cover flange-The cover flange and meter body form a space between them. Steam condenses in the space, so that condensate seals the diaphragm by water, thus protecting it.
Drain plug -This plug is intended to remove condensate from the self water seal.
Types of output
The steam flow meter provides two types of output: analog and pulse.
Analog output
The instantaneous flow rate, pressure, or temperature can be selected as an analog output signal of 4 to 20 mA DC.Analog signal of 4 to 20 mA DC
Number of output signals:1
Output selection: Instantaneous flow
rate, pressure, or temperature
Pulse output
The steam flow meter can generate a pulse output signal showing the accumulated flow rate. The pulse frequency can be adjusted to be within a range from 0 to 200 Hz by varying pulse weight. The accumulated flowrate is held if the power is turned off.
Type of output:
Pulse signal (pulse frequency ranging from 0 to 200 Hz)
Number of output signals:1 Output selection: Accumulated flow rate
Mass flow rate
On the assumption that saturated steam flows through the piping, the steam flow meter calculates the mass flow rate from pressure difference and steam density. Then the meter outputs the calculated value. The pressure difference and steam density are obtained using a primary-pressure measurement and steam tables incorporated in the steam flow meter. It can provide the mass flow rate as an analog or pulse output.
