Toshiba LQ500 Zero point water valve, Vent valve, Drain valve, Sampling valve, Wiring Precautions

LQ500

(7)Install an adjustable piping mechanism if there is a possibility that the detector pipe may not fit between mating flanges.

(8)Install the LQ500 in a place where enough water pressure is applied. Therefore, it is recommended that the LQ500 be installed as far away as possible from the pipe outlet opened to atmosphere. This is to prevent the effects of air being trapped in the liquid.

(9)If there is a possibility of no liquid flow or uneven liquid distribution occurring when a pump is off, use an external synch control signal to operate the LQ500 only when the pump is working.

(10)Provide a stop valve at upstream and downstream of the detector, and between stop valves and the LQ500 provide the four valves described below with a stop valve attached to each: 1) sampling outlet valve; 2) zero point water inlet valve; 3) vent valve; and 4) drain valve. If it is not possible to stop the fluid at the point where the LQ500 is installed, provide a bypass pipe with a stop valve provided in the middle. These valves are needed to drain the fluid from the detector pipe and fill it with drinking water (density or consistency 0%) to adjust the zero point. See Figures 6 and 7.

(11)Use gaskets for piping of the size conformed to flange rating and of the material appropriate for the liquid to be measured.

NOTE:

•Zero point water valve:

Used to supply drinking water (density or consistency 0%) to the detector pipe for zero point adjustment. Install this valve at the top of the pipe in the case of horizontal installation. It is recommended that a 1-inch ball valve be installed on the top of the pipe and zero point water supplied through this inlet using a vinyl hose etc.

Note: If valve water pipe is connected to this valve, air cannot be extracted. Therefore, another valve (vent valve) is needed to extract air.

•Vent valve:

Used to vent process fluids to open air when performing zero adjustment. This helps the drinking water (density or consistency 0%) enter the detector pipe easily. Install this valve on the top of the pipe in the case of horizontal installation.

•Drain valve:

Used to drain the fluids before supplying drinking water (density or consistency 0%) to the detector pipe for zero adjustment. Install this valve at the lowest point of the pipe. It is recommended that a 1-inch ball valve be installed at the lowest point of the pipe.

•Sampling valve:

Used to extract fluids for manual analysis.

Install this valve to the side of the pipe in the case of horizontal installation. It is recommended that a 1-inch ball valve be installed to the side of the pipe.

Stop	Stop valve
valve		Vent valve
		Zero point water pipe
	LQ500	Zero point water valve
Bypass		Drain valve
pipe		Drain pipe

Stop valve

Flow direction

(from down to up directions)

Figure 6. Recommended Installation

(vertical installation)

Vent valve	Zero point
	water valve
Stop valve LQ500	Stop valve
Sampling	Drain
valve	valve
Stop valve	Bypass pipe

Figure 7. Recommended Installation (horizontal installation)

■Wiring Precautions

(1)Provide a switch and a fuse to isolate the unit from the mains power for ease of maintenance.

(2)Ground the LQ500 with 100 ohm or less ground resistance. Do not use a common ground shared by other power equipment.

(3)Use the accessorious cables for communication and power supply between detector and converter. Connect cables to the terminals that match the marking on the cables.

(4)Use a sheathed cable with 2mm2 cross-sectional area for AC power cable.

(5)The cables should be free from vibration and should have no slack in the cables.

(6)Wire the LQ500 output in conduit separated from those of AC power cable, control signals, alarm signal or other cables which could become the source of noise.

(7)Use a 2-wire shielded sheathed cable to wire the LQ500 output (4-20mAdc) and conductivity signal. Ground the shielded cable on the receiving instrument side for both cable.

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