Oval EX DELTA II, Instructions Manual

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D-583-2N-E
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11. MAINTENANCE
As long as your DELTA Flowmeter is placed in service under proper operating conditions, it will perform
satisfactorily over extended periods of time. But scale, sludge and other foreign matter contained in the
metered fluid could adhere to the inner walls of your meter and degrade meter performance in time. For this
reason, periodic disassembly and inspection is suggested.
11.1 Disassembly and Inspection
◇ Time for disassembly and inspection ◇
(1) Six months after the first time operation.
(2) According to the conditions observed in () above, determine the second time disassembly and inspection.
(Once a year is suggested under normally encountered operating conditions.)
◇ Inspection points ◇
() Probe (probe body and bluff body) for deposits.
(2) Observe the output waveform from the amplifier board in the amplifier and make sure that it conforms to
the waveform shown in the section under the topic "TROUBLESHOOTING" in the preamplifier instruction
manual.
11.2 How to Disassemble and Inspect
NOTE: See "Section 4, EXPLODED VIEW AND PARTS LIST, FIXED TYPE" on pages 36 and 37.
() Probe Inspection
Taking off the hex bolt (07) and three hex socket head setscrews (09A), the probe body (0) can be
separated. Inspect the probe body (0) on its inner walls and the bluff body (05) for condition and clean.
Foreign matter in the capillary slots (a total of four places) on the sides of bluff body in particular must be
removed thoroughly. Adhere to the following instructions at this point:
CAUTION
1. Do not force the bluff body because it contains the sensor (201) installed and accessible through
capillary slots.
2. Sharp edges of the bluff body play an important role for maintaining meter accuracy. Exercise care
not to damage them.
Following inspection, install in place. Align the locating pin on the probe body (101) with the mating
pin slot in the bluff body (105) at this time.
(2) Sensor Removal
If it is desired to remove the sensor for sensor replacement or other reason, proceed as follows:
[1] Firstly separate the preamplifier in the following manner:
(a) Remove power and disconnect external connections.
(b) Remove the top cover.
(c) Loosening the four fitting screws (311) securing the output board, pull out the connector to the
amplifier board and separate the output board complete with a shield strip.
(d) Disconnect the three sensor leads connected to the amplifier board (304).
(e) Taking off the four fitting screws (214) holding the preamplifier, remove the preamplifier housing (301).
[2] Separate the fitting boss (104) in the following manner:
(a) Remove the C-shaped stop ring (209)*, O-ring retainer (208)* and O-ring (207).
(NOTE: Parts marked with an asterisk * are required for flameproof preamplifiers PA05, PA05I,
PA05S and separately mounted preamplifier.)
(b) Taking off the four hex socket head setscrews (109B), remove the fitting boss (104).
[3] Sensor Removal
Taking off the four hex socket head bolts (08) in this state, the sensor (20) can now be separated. Do
not force but pull it slowly until out.
(3) Sensor Installation
Reverse the order of steps (2) above, observing the following instructions:
CAUTION
1. When installing the sensor, make sure that the O-ring (204) is in place. If this O-ring is distorted or
otherwise damaged, replace with a new one.
2. Align the locating pin of the sensor (201) with the pin slot of the shaft assembly (102) and bluff body (105).
You cannot disassemble sensor (201).
CAUTION: The sensor (201) cannot be disassembled. If found to be defective, the
sensor should be replaced as an assembly.