Specify eight technical requirements that you would consider important, when deciding upon a particular control valve?
1] I assume that by control valve you mean a variable orifice valve, not an on/off valve. 2] An answerer to your other question listed Metallurgy, temperature, pressure and shutoff requirement To which I note that if you need a tight shutoff you should not trust a control valve to do that, but should add an on/off valve in series. Also, metallurgy covers corrosion requirements but not obviously so 3] To which I add: flow rate [or Cv] and pressure drop fail open or fail closed response time signal input [3-15 psi, 4-20 mA, 1-5V, etc] connections [ie, fitting type] packed vs sealed might need to look at hard seat materials and/or replaceable seats, to control erosion reliability, ease of maintenance, availability of spares, timing on that vendor permanence [ie, are they entering bankruptcy ?] Cost