简介
·标准和低断面面积流速传感器
·美国ISCO 4250速度面积便携式流速超声波测量仪探头的流线型造型避免了有机物残渣和水流中化学成分的腐蚀
·密封设计能避免油脂堵塞，从而使其长期可靠运行
·标准探头适用于较大管径，带有高浓度悬浮固体和气泡的混浊水流
·低断面探头适用于浅流，水位可低至1英寸（25毫米） ·可选择电话调制器-提供获取远程数据，语音信息，和警报信号
·可以支持不超过3个单独的内部4-20mA输出
·美国ISCO 4250速度面积便携式流速超声波测量仪即便在槽或堰不适用、探头被浸没、满管、过载或有逆流发生的地方
·4250均可为您提供较高的测量，现场显示和打印

特点
·打印显示一体式结构
·带有微处理器的数字探头确保读数稳定（防止液位偏差）
·无需量程校准现场一点校准
·没有温度漂移
·自动修正泥沙液位
·对各种不同的液体自动增益控制
·传感器不受液位降低影响

应用场合
·容量评价
·入流和渗流研究
·下水道溢流研究
·生活污水评估
·明渠流量测量

技术参数
液位测量方法 浸入式压力传感
液位测量范围 0.015至3.05m，可延伸至0.015-9.14m
液位准确性 ±0.008/m
速度测量方法 多普勒超声波方法
频率 500KHz
速度范围 -1.5至6.1m/s
速度准确性 -1.5至1.5m/s，±0.03m/s，1.5至6.1m/s, ±2%
模块存储温度 -40~60℃
操作温度 -18±～60℃
电源 12～14V DC
防护等级 IP65
数据存储间隔 1分钟到120分钟可选择
模块尺寸 40.6＊29.2＊26.7cm
温度影响 ±0.0027m/℃
标准传感器尺寸 16.8＊4.1＊3.0cm
标准传感器重量 0.96kg
电缆线长 7.6m， 可延长至15.2m

The sensor on the Isco 4250 uses patented Doppler technology to directly measure average velocity in the flow stream. An integral pressure transducer measures liquid depth to determine flow area. The 4250 then calculates flow rate by multiplying the area of the flow stream by its average velocity.

The 4250 gives you greater accuracy in applications where weirs or flumes are not practical, or where submerged, full pipe, surcharged and reverse flow conditions may occur. With area velocity you don’t have to estimate the slope and roughness of the channel. And Isco’s exclusive 500 kHz Doppler penetrates farther into deep flow streams than 1 MHz systems, whose shorter wavelength can cause them to give “nearsighted” velocity measurement in typical wastewater applications. The Doppler system continuously profiles the flow stream, eliminating profiling and calibration required by electromagnetic systems.

Standard Features


4200 Series
- Built-in flow conversions for most applications, including Manning formula, data points, or equation for special situations.
- Set up with or without a computer. All setup functions can be done either via onboard keypad and two-line x 80-character backlit LCD, or by connection to PC with Flowlink software.
- Built-in dot matrix printer gives you an accurate, on-site printout
- Internal memory stores over 2 months of flow, rainfall, parameter, and sample data at 15 minute intervals.
- Outputs for Sampler activation, alarm outputs
- Inputs for connection to 674 Rain Gauge and multiparameter water quality sonde,

4250 Area Velocity
- Sealed Area-Velocity sensor resists fouling by oil and grease. Streamlined shape sheds debris.
- Choice of standard (10 ft) and extended (30 ft) level measurement range.
Applications


Accurate open channel flow measurement without a weir or flume

Pretreatment Compliance

Stormwater Runoff Monitoring

Permit Enforcement

Sewer Flow Monitoring

Combined Sewer Overflow Studies

Inflow and Infiltration Studies

River and Stream Gauging
Options and Accessories


Choice of Standard and Low Profile Area Velocity Sensors.
- Standard Sensor is recommended for larger pipes and turbid flows with high concentrations of suspended solids and entrained air.
- Low Profile Sensor is recommended for shallows flows, typically down to 1" (25 mm).

Optional telephone modem - provides remote data retrieval, voice messaging, and dial-out alarm conditions

Analog Outputs - up to 3 isolated internal 4-20 mA outputs

Mounting rings for installation of probe in round pipes from 6 to 15 inches in diameter

Non-resettable totalizer

674 Rain Gauge

581 RTD data retrieval device downloads up to 20 meters

201 pH module adds pH and temperature measurement/logging

YSI 600 Multi-Parameter Water Quality Monitor

Suspension equipment (to hang flowmeter in manhole)
Specifications
Size (H x W x D): 17.0 x 11.5 x 10.5 in. (43 x 29 x 26.7 cm) (without power source)
Weight: 17.3 lbs (7.8 kg) (without power source)
Material: High-impact molded polystyrene structural foam
Enclosure: NEMA 4X (iP65)
Power: 12 to 14V DC, 14 mA average at 12.5V DC
Typical Battery Life (printer set at 1 in/hr, 1 minute level reading interval, 5 minute velocity reading interval)
934 Nickel-Cadmium Battery: 8 to 11 days
946 Lead-Acid Battery: 12 to 16 days
948 Lead-Acid Battery: 2½ to 3 months
Program Memory: Non-volatile, programmable flash. Updateable without opening enclosure.
Display: Backlit LCD, 2-line, 80-character (5.5 mm high x 3.2 mm wide)
Level-to-Area Conversions
Channel shapes: Round, U-shaped, rectangular, trapezoidal
Data points: Four sets of 50 level-area points
Level-to-Flow Rate Conversions
Weirs: V-notch, rectangular, Cipolletti
Flumes: Parshall, Palmer-Bowlus, Leopold-Lagco,Trapezoidal, H, HS, HL
Manning Formula: Round, U-channel, rectangular, trapezoidal
Data Points: Four sets of 50 level-flow rate points
Equation: Two-term polynomial
Totalizers
LCD: Total, forward, and reverse flow; 9 digits each, floating decimal point, resettable
Mechanical (optional): Total flow, 7 digits, non-resettable
Area Velocity Sensor (See separate specifications for low-profile sensor)
Size (LxWxH): 6.6 x 1.6 x 1.2 inches (16.8 x 4.1 x 3.0 cm)
Weight, incl. cable: 2.1 lbs (0.96 kg) for standard probe with 25 foot cable; 3.9 lbs (1.8 kg) for extended range probe with 50 ft cable.
Ambient Operating Temperature Range: 0° to 140°F (-18° to 60°C)
Compensated Temperature Range: 32° to 140°F (0° to 60°C)
Materials: Polybutadiene-based polyurethane, stainless steel; PVC and CPVC cable
Velocity Measurement
Method: Doppler Ultrasonic, 500 kHz
Velocity range: -5 to +20 ft/s (-1.5 to 6.1 m/s)
Level Measurement
Method: Submerged pressure transducer
Standard range probe: measurement range 0.05 to 10 ft (0.015 to 3.05 m); max level 20 ft (6.1 m)
Extended range probe: measurement range 0.05 to 30 ft (0.015 to 9.14 m); max level 40 ft (12.2 m)
Standard probe accuracy (Non-linearity, repeatability, and hysteresis at 25°C (77°F). Max error for indicated level range.
0.033 to 5.0 ft (0.01 to 1.52 m): ±0.008 ft/ft (±0.008 m/m)
>5.0 ft (>1.52 m): ±0.012 ft/ft (±0.012 m/m)
Extended probe accuracy (Non-linearity, repeatability, and hysteresis at 25°C (77°F). Max error for indicated level range.
0.05 to 15 ft (0.015 to 4.57 m): ±0.03 ft (±0.009 m)
0.05 to 21 ft (0.015 to 6.4 m): ±0.09 ft (±0.027 m)
0.05 to 30 ft (0.015 to 9.14 m): ±0.3 ft (±0.09