Discharge measurement technique is roughly OK reduce the following kinds:

(1) uses Bernoulli equation principle, the poor flow pressing type that will reflect discharge through measuring fluid difference to press signal measures a way;

(2) reachs through measuring fluid velocity of flow directly the speed type discharge of discharge measures a way;

(3) uses standard minor volume to measure the cubage type of discharge continuously;

(4) is the mass flow of the purpose to measure a way with measuring fluid mass flow.

2. The classification of flow meter

3. The main technique parameter of flow meter

(1) discharge limits

The limits of the largest flow that discharge limits points to to flowmeter can be measured and the least flow.

(2) span and span are compared

The largest flow and the least flow is worth difference inside discharge limits call the span of flowmeter. The ratio of the largest flow and the least flow calls span comparing, also say the limits of flowmeter is spent.

(3) allows accuracy class of sum of errors

Flow meter leaves permission the biggest error in regular job requirement of the regulation, the permission that calls this flow meter error, cite with the biggest opposite sum of errors commonly the error will express.

The accuracy class of flow meter differentiates according to permitting the bulk of the error, its accuracy class has: 0.02, 0.05, 0.1, 0.2, 0.5, 1, 1.5, 2.5 wait.

(4) pressure loss

Pressure losing size is index of a of flow meter type selecting main technique. Pressure loss is small, the fluid can be used up small, the dynamical demand of transport fluid is little, measure cost low. Conversely criterion specific power consumption is big, economic benefits is reduced accordingly. The pressure loss of reason hope flowmeter heals small had healed.