Variable-Area Flow Meter with Alarm Switch for Immediate Abnormality Feedback

The variable-area flow meter with alarm switches is a setup where BJ01 upper limit alarm and BJ02 lower limit alarm switches are added to the existing flow meter's measurement tube on the dovetail guide rails. The alarm switches can signal at any flow value, whether it be maximum, intermediate, or minimum. When the magnetic float reaches or exceeds the switch position, it utilizes the bistable magnetic action of a reed switch, which enables the flow meter and the magnetic float to open and close contacts. This mechanism is used in conjunction with relay components and other elements to meet the requirements for audible and visual alarms.

Specifications
Working Principle
Structure
Video

Specification

Table 1: SVF LZM Series Panel-Type Variable-Area Flow Meter With Alarm Switch Specifications
Model	Measurement Range			Interface Thread	Accuracy (±%)
Model	Liquid (GPM)	Liquid (LPM)	Gas (Nm³/h)	Interface Thread	Accuracy (±%)
SF LZM-15, SF LZM-15J	0.2–2	0.8–8	–	ZG1/2"M	±4
	0.3–3	1–11	–	ZG1/2"M	±4
	0.5–5	2–18	–	ZG1/2"M	±4
	1–7	2–28	–	ZG1/2"M	±4
SF LZM-20, SF LZM-20J	2–10	8–40	6–60, 16–80, 16–160	ZG3/4"M	±4
	2–16	8–60	6–60, 16–80, 16–160	ZG3/4"M	±4
	2–20	8–80	6–60, 16–80, 16–160	ZG3/4"M	±4
SF LZM-25, SF LZM-25J	1.5–15	6–60	–	ZG1"M	±4
	3–13	10–50	–	ZG1"M	±4
	4–24	10–100	–	ZG1"M	±4
	5–35	10–130	–	ZG1"M	±4
	5–45	10–170	–	ZG1"M	±4
SF LZM-15Z	0.1–1	0.5–4	0.3–3, 0.4–4, 0.6–6, 1–10, 2.5–25, 4–40	ZG1/2"M, ZG1/4"F	±4
	0.15–1.5	0.6–6	0.3–3, 0.4–4, 0.6–6, 1–10, 2.5–25, 4–40	ZG1/2"M, ZG1/4"F	±4
	0.2–2	1–7	0.3–3, 0.4–4, 0.6–6, 1–10, 2.5–25, 4–40	ZG1/2"M, ZG1/4"F	±4
	0.3–3	1–11	0.3–3, 0.4–4, 0.6–6, 1–10, 2.5–25, 4–40	ZG1/2"M, ZG1/4"F	±4
	0.5–5	2–18	0.3–3, 0.4–4, 0.6–6, 1–10, 2.5–25, 4–40	ZG1/2"M, ZG1/4"F	±4
SF LZM-25Z	1–10	5–35	–	ZG1"M	±4
	1–15	5–50	–	ZG1"M	±4
	2–14	10–50	–	ZG1"M	±4
	2–20	10–70	–	ZG1"M	±4
	5–35	10–130	–	ZG1"M	±4
	5–40	10–150	–	ZG1"M	±4
	5–45	10–170	–	ZG1"M	±4
	–	0.3–2.1 m³/h	–	ZG1"M	±4
	–	0.6–3 m³/h	–	ZG1"M	±4
	–	0.6–4.2 m³/h	–	ZG1"M	±4
SF LZM-15G	0.1–1	0.5–4	1–10, 1.6–16, 2.5–25, 4–40	G1/2"F	±4
	0.2–2	1–7	1–10, 1.6–16, 2.5–25, 4–40	G1/2"F	±4
	0.5–5	1.8–18	1–10, 1.6–16, 2.5–25, 4–40	G1/2"F	±4
	1.5–9	400–2000 LPH	1–10, 1.6–16, 2.5–25, 4–40	G1/2"F	±4
SF LZM-20G	1–10	6–60	–	G3/4"F	±4
SF LZM-25G, SF LZM-40G	1–15	5–60	–	25G, G1"F 40G, G1-1/2"M	±4
	2–20	10–70	–	25G, G1"F 40G, G1-1/2"M	±4
	5–30	20–110	–	25G, G1"F 40G, G1-1/2"M	±4
	5–40	20–150	–	25G, G1"F 40G, G1-1/2"M	±4
SF LZM-50G	20–80	80–300	100–500	G2"F, G2"M	±4
	20–100	80–360	120–600	G2"F, G2"M	±4
	40–120	150–450	300–850	G2"F, G2"M	±4
	50–150	190–560	400–1200	G2"F, G2"M	±4
	60–200	220–750	500–1400	G2"F, G2"M	±4

Table 2: lSVF LZS Series Plastic Pipe Type with Alarm Switch Specification
Model	Nominal Diameter (mm)	Measurement Range			Accuracy (±%)	Allowed Measured Medium Condition
		Long Tube Type	Short Tube Type			Temperature (°C)	Pressure (MPa)
SVF LZS-15	15	10–100 L/h, 16–160 L/h, 25–250 L/h, 40–400 L/h, 60–600 L/h		5–50 L/h, 10–100 L/h, 16–160 L/h, 25–250 L/h, 40–400 L/h, 50–500 L/h, 60–600 L/h, 100–1000 L/h	±4	0–60°C	≤0.6
SVF LZS-25	25	100–1000 L/h, 160–1600 L/h, 250–2500 L/h		100–1000 L/h, 160–1600 L/h, 4–40 L/min, 250–2500 L/h
SVF LZS-32	32	–		0.4–4 m³/h, 0.6–6 m³/h
SVF LZS-50	50	0.4–4 m³/h, 0.6–6 m³/h, 1–10 m³/h, 1.6–16 m³/h		1–10 m³/h, 1.6–16 m³/h
SVF LZS-60	60	–		2.5–16 m³/h, 5–25 m³/h, 8–40 m³/h, 12–60 m³/h
SVF LZS-100	100	14–90 m³/h, 18–120 m³/h, 20–150 m³/h, 25–180 m³/h, 25–200 m³/h		14–90 m³/h, 18–120 m³/h, 20–150 m³/h, 25–18 0m³/h, 25–200 m³/h
SVF LZS-125	125
SVF LZS-150	150
Note: SVF LZS-100, 125, 150 specifications flowmeter can be customized with alarm switch

Table 3: SR LZB Small Glass Rotor with Alarm Switch Specification
Model		LZB-6	LZB-10	LZB-15	LZB-25
Nominal Diameter (mm)		φ6	φ10	φ15	φ25
Measurement Range	Liquid (L/h)	1–10	6–60	*6–60	40–400
		2.5–25	10–100	*8–80	60–600
		4–40	16–160	16–160	100–1000
		6–60	25–250	25–250	*160–1600
		–	–	40–400	–
	Gas (Nm³/h)	0.06–0.6	0.1–1	0.25–2.5	*0.8–8
		–	0.16–1.6	0.4–4	1–10
		–	0.25–2.5	0.6–6	1.6–16
		–	0.4–4	–	2.5–25
		–	0.6–6	–	–
		–	–	–	–
		–	–	–	–
		–	–	–	–
		–	–	–	–
Accuracy (±%)		2.5	2.5	2.5	1.5
Operating Pressure (MPa)		≤1	≤1	≤1	≤0.6
Note: Flow rates marked with "*" are special flow rates

Table 4: lSR LZB Large Glass Rotor with Alarm Switch Specification
Model		SR LZB-40	SR LZB-50	SR LZB-80	SR LZB-100	SR LZB-100
Nominal Diameter (mm)		ɸ40	ɸ50	ɸ80	ɸ100	ɸ100
Measurement Range	Liquid (L/h)	160–1600	*160–1600	1–10 m³/h	5–25 m³/h	*20–90 m³/h
		*180–1800	400–4000	1.6–16 m³/h	*6–35 m³/h	*20–100 m³/h
		250–2500	600–6000	*2–20 m³/h	8–40 m³/h	*30–100 m³/h
		*300–3000	*800–8000	*3–25 m³/h	*12–60 m³/h	*50–120 m³/h
		*400–4000	*1–10 m³/h	*8–40 m³/h	*16–80 m³/h	–
	Gas (Nm³/h)	*1–5 m³/h	*4–16 m³/h	–	–	–
		*1.5–6 m³/h	–	–	–	–
		4–40	*6–60	50–250	*60–200	*300–1500
		*5–50	10–100	80–400	*80–400	*300–1600
		6–60	16–160	*750–7500 L/min	*100–500	*400–2000
		*7–70	*20–200	*6–60	120–600	*500–2500
		*8–80	*30–300	–	200–1000	–
		*10–100	*50–250	–	–	–
		–	*80–400	–	–	–
Accuracy (±%)		1.5	1.5	1.5	1.5	1.5
Operating Pressure (MPa)		≤0.6	≤0.6	≤0.4	≤0.4	≤0.4
Note: Flow rates marked with "*" are special flow rates

Table 5: SR LZB-VA/WA/FA30S Type Rotameter with Alarm Switch
Model	Nominal Diameter DN (mm)	Measurement Range		Accuracy (±%)	Operating Temperature (°C)	Operating Pressure (MPa)
Model	Nominal Diameter DN (mm)	20 °C water (L/h)	20 °C Air: 101325 Pa (m³/h)	Accuracy (±%)	Operating Temperature (°C)	Operating Pressure (MPa)
SR LZB-VA30S-15, SR LZB-FA30S-15, SR LZB-WA30S-15	15	4–40, 6.3–63, 10–100, 12–120, 16–160, 20–200, 25–250, 30–300, 36–360, 40–400, 46–460, 63–630, 65–650, 75–750	0.12–1.2, 0.2–2, 0.3–3, 0.4–4, 0.5–5, 0.6–6, 0.8–8, 0.9–9, 1.2–12, 2–20	±1.5	-20 °C to +80°C	≤1
SR LZB-VA30S-25, SR LZB-FA30S-25, SR LZB-WA30S-25	25	40–400, 50–500, 63–630, 80–800, 100–1000, 120–1200, 160–1600, 200–2000, 250–2500, 300–3000	1.6–16, 2–20, 2.5–25, 3–30, 4–40, 5–50, 6–60			–
SR LZB-VA30S-40, SR LZB-FA30S-40, SR LZB-WA30S-40	40	160–1600, 200–2000, 250–2500, 300–3000, 400–4000, 600–6000	5–50, 6–60, 8–80, 9–90, 12–120			≤0.9
SR LZB-VA30S-50, SR LZB-FA30S-50, SR LZB-WA30S-50	50	250–2500, 300–3000, 400–4000, 500–5000, 630–6300, 800–8000, 1000–10000, 1500–15000, 4000–16000	10–100, 12–120, 16–160, 20–200, 30–300			≤0.7

Technical parameters

Maximum Operating Voltage: DC 100V / AC 100V
Maximum Operating Current: 0.3A
Maximum Switching Current: 0.5A
Maximum Interrupting Power: 0.5VA
Operating Temperature Range: 0°C to 55°C
Insulation Impedance: >10^9 Ω
Protection Level: IP65
Hysteresis (Open or Close Position): ≤4 mm
Dimensions: 42x20x38 mm

Applications and Functions

Upper Limit Alarm: When the magnetic float is exactly at the switch set position, the contact is closed. When the magnetic float is above the switch set position, the contact remains closed. When the magnetic float is below the switch set position, the contact opens.
Lower Limit Alarm: When the magnetic float is exactly at the switch set position, the contact is closed. When the magnetic float is below the switch set position, the contact remains closed. When the magnetic float is above the switch set position, the contact opens.