YOKOGAWA vigilantplant DM8, User Manual

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<3. INSTALLATION, PIPING AND WIRING>
3-3
IM 12T03A01-02E
3.1.2 Sampling Unit for Vibration Type Density Meter
This section describes a sampling that is provided by user for the density meter.
The sampling equipment is equipped with valves, a thermometer, a flowmeter, etc., and is
located near to process pipe and the density detector.
The sampling equipment is used to provide good condition to measure liquid density, easy to
monitor measuring and maintenance condition such as calibration and cleaning the vibrator.
Install the sampling equipment according to the following. For details of piping from process to
the equipment, refer to the section 3.3.
(1) Flow Diagram
Figure 3.5 shows a flow diagram of a typical sampling equipment. Model VD6SM sampling unit of
Yokogawa is also designed according to this diagram.
STEAM IN
CONDENSATE OUT
V2
a
a
V1
b
ST1
a'
a'
b'
TI
F
FM
NV1
PI
NV2
DD
NV3
NV4 BV1
Element specifications
F: Strainer body; 316 SS
Element; 316 SS, or Ni (option)
PI: Pressure gauge, 0 to 1MPa or 0 to 2MPa, 316 SS
TI: Thermometer. 0 to 100 °C or 0 to 150 °C, 316 SS
FM: Flowmeter, tapered metal tube flowmeter, 1 to 10 L/min, 316 SS
BV1: Ball valve, 316 SS
NV1 to 4: Needle valve, 316 SS
DD: Density detector
V1, V2: Valve
ST1: Steam trap
SAMPLE IN
SAMPLE OUT
Figure 3.5 Flow Diagram
In Figure 3.5, each element of the sampling equipment is shown F (filter) is usually 80 meshes,
prevents a solid from entering into the sampling line. TI (thermometer), FM (flowmeter) and PI
(pressure gauge) are necessary to monitor measuring liquid. NV1 (needle valve) is required to
control flow rate of a sample liquid. BV1 (ball valve) and NV4 (needle valve) are used for stopping
measuring liquid when the vibrator is cleaned or calibration is performed using standard solution.
(The needle valve is also used for adjusting flow rate). NV2 (needle valve) and NV3 (needle
valve) are used for draining liquid from the vibrator or for picking up sample for manual analysis.
When viscosity of a measuring liquid is to be lowered, for example, the pour point of measuring
liquid is high, arrange the density detector and the liquid pipe should be warmed individually.
Steam pipe can be connected to the density detector and the liquid pipe can also be traced by
steam pipe. V1 (“stop” valve) is to supply the steam to the density detector and V2 (“stop” valve)
is to supply the steam to tracing pipe. ST1 (steam trap) is used to drain condensed water.
(Note1): Kind of valve used in the sampling equipment varies with the purpose of use. This instruction manual gives a detailed name of
equipment (for example, ball valve) used for limited purpose, and shows a general name within “ ” when equipment type is not
restricted (for example “stop” valve).
(Note2): Density Detectors of Model VD6D (general purpose type) and VD6DF (flameproof) have steam pipe connections, however,
Model VD6DS (sanitary use) has not the connections.
(Note3): Model VD6SM sampling unit, a product of Yokogawa, is applied to Model VD6D (general purpose type) or Model VD6DF
(flameproof type). It is not recommended for the Model VD6DS (sanitary use) used for food.
5th Edition : Dec. 11, 2015-00