1 Overview
FFZ-01 type digital water meter is based on the People''s Republic of China GB 21327-2007 evaporation water evaporator "," Ministry of water conservancy and electric power "and" evaporation observation standard SD265-88 Chinese Meteorological Bureau in 2003 edition of "meteorological observation standard" requirements for manufacturing, automatic observation of water surface evaporation process.
Evaporation type FFZ-01 digital meter by evaporation (pool) and digital surface evaporation sensor for the observation of evaporation equipment, complete the evaporator with special collection controller and automatic data acquisition and processing of evaporation up drainage control, to achieve high precision real-time on-line measurement of water surface evaporation process.
The evaporation sensor of this instrument uses a digital coding sensor with resolution of 0.1mm, which can work stably and reliably under the environment of high temperature, high humidity, wind and wave and sand dust.

2 structure and working principle
The water evaporation of 2.1 FFZ-01 type digital meter comprises an evaporation barrel, hydrosphere, connecting pipe, water level encoder, float, measuring cable, balance hammer, static bucket, circular support plate, leveling device, automatic feeding device, water collecting controller (hereinafter referred to as the collector). When installing the evaporation barrel, connecting pipe, static barrel connector; water level encoder, collector, leveling balance device installed in the circular plate on static tank; a float, a measuring cable, cable hanging in the balance hammer respectively two groove measuring wheel circumference level encoder, the float installed in static water bucket. When the water level in the evaporating bucket causes the water level to drop, the water surface in the static bucket falls synchronously, and the buoy pulls the cable to drive the measuring wheel and the encoder to rotate, and the encoder can output the coding data corresponding to the water surface falling amount. The collector calculates the water surface evaporation by collecting the water level variation in the corresponding period.
2.2 the instrument is equipped with stainless steel windproof and dustproof outer cover. The static bucket adopts the same half buried structure as the evaporating bucket, so as to ensure the water temperature in the static bucket and the evaporating bucket as much as possible, so that the sensor can work reliably in the bad outdoor environment.
2.3 for evaporation type FFZ-01 digital meter, evaporation barrel diameter of 612mm, the area is 3000cm2, the static bucket work section diameter of 240mm, the area is 453.27cm2, when the evaporation evaporation in the barrel is 0.1mm (which is equivalent to the removal of water from evaporation in 30ml float water level variation). The H is only 0.086896 mm.
Among them, the h= S1 / (S0 + S1) / =457.27 (3000+453.27) =0.086896 (mm)
Type: S0=3000cm2
S1= PI R2 =3.1416 x (12cm) 2 =453.27cm2
Therefore, when the data measured by the spiral probe in the evaporation bucket is relative to the data measured by the digital evaporation meter, the actual measurement of the evaporation rate should be divided by 0.086896 by the manual needle measuring value.
When the 2.4 FFZ-01 type digital water surface evaporation meter is matched with the 20 square meter evaporation pool, because the area of the static water bucket of the sensor is only 2.4 per thousand of the evaporation pool area, the influence of the exchange between the static bucket and the evaporation pool can not be considered basically. The connecting pipe can be connected with the evaporation tank directly, or the static bucket of the evaporation sensor is installed in the evaporation pool of 20 square meters. (when the 20m2 evaporation tank is used together, the corresponding diameter measuring wheel should be matched and should be supplemented when ordering).
When the water level of the evaporation bucket (pool) is low to a predetermined value when the water level of the evaporation bucket (pool) is 2.5 FFZ-01, the water collecting device starts the water replenishing device to supply water. When there is a rainfall, when the water level in the evaporation bucket (pool) rises to a predetermined height, the drainage device can be started to drain by collecting the controller. The water level in a static bucket can always be monitored.
2.6 using this evaporator, we can only accurately measure the water surface evaporation in non precipitation period. If you want to include the daily evaporation of rainfall measurement period, according to the National Bureau of hydrology and the national weather service requirements, you must also configure the resolution of 0.1mm high precision gauge, the measurement error is less than or equal to (1 ~ 2) and other related devices can be achieved:%.

3 technical parameters
3.1 resolution of evaporation measurement: 0.1mm;
3.2 evaporation measurement accuracy: evaporation is less than 10mm, the measurement error: less than 0.3mm;
The measurement error of evaporation is larger than 10mm, less than: (0.3mm+1%F.S));
3.3 evaporation measurement range: no less than 20mm;
3.4 output interface: RS-485;
3.5 supply voltage: 12V/DC (-5%~+25%);
3.6 environmental temperature: 0 ~+55 c;
3.7 storage temperature: -10 C ~+60 C.