Orifice plate throttling and control valve throttling

A orifice plate is a flow measurement element used to measure flow rate； A control valve is a regulating device used to control flow; the functions of the two are different.

This post was last edited by ylb913 on 2015-8-5 at 19:59. There are flow orifice plates and throttling orifice plates; the throttling capacity of these plates is fixed, whereas that of control valves can be adjusted at any time.

Orifice plates include flow-orifice plates and flow-limiting orifice plates, whose throttling capacity is standardized by the state. The throttling level of the control valve can be adjusted at any time; agreed

Well, one is an inherent attribute, while the other is manual or automatic adjustment

The flow characteristics of valves: Different flow characteristics result in different valve openings； ① The flow rate characteristic shows large changes at first and then becomes more stable ； ② The linear flow characteristic means that the degree of opening of the valve is directly proportional to the flow rate; in other words, when the valve is open to 50%, the flow rate through the valve is also 50% ； ③The flow characteristic of wait-hundred mode is the opposite of that of quick-open mode: there is little change at first, but it increases significantly later on. There is no definite formula for the relationship between valve opening degree and flow rate and pressure. Their relationship can only be expressed in a general functional form; specific details require reference to particular test curves. The relationship between the relative flow rate Q/Qmax of the control valve and the relative opening degree L/Lmax: Q/Qmax = f(L/Lmax). The relationship between the relative flow rate Q/Qmax of the control valve, the relative opening degree L/Lmax, and the pressure difference across the valve: Q/Qmax = f(L/Lmax) × (dP1/dP)^(1/2). The inherent flow characteristics of a control valve depend on the shape of its valve element; the simplest form is a linear flow characteristic: the relative flow rate of the control valve is directly proportional to its relative opening degree, meaning that the change in flow rate resulting from a single stroke of movement is constant. The ratio of the maximum to minimum flow rates that can be controlled by the valve is called the adjustable ratio, denoted as R, where R = Qmax/Qmin. For a linear flow characteristic, the relationship between flow rate and valve opening is: Q/Qmax = (1/R). When the valve is open to half its maximum position, Q/Qmax = 51.7%. For a proportional flow characteristic, Q/Qmax = R^(L/Lmax-1); at half opening, Q/Qmax = 18.3%. For a fast-opening flow characteristic, Q/Qmax = (1/R)^(1/2), and at half opening, Q/Qmax = 75.8%

Throttling with control valves is different from throttling using orifice plates; the amount of flow that can be throttled through control valves is adjustable, whereas it remains constant in the case of orifice plates. This is the difference.

What is mentioned on the sixth floor is exactly what I need. Thank you so much

Orifice plates provide a relatively coarse flow control, while control valves offer more precise regulation

Orifice plate flow rate cannot be adjusted, as the gap in its center is fixed. It is generally used at loose connections; we install it there. There are also orifice plate flow meters