pneumatic sleeve control valve

pneumatic sleeve control valve

Pneumatic sleeve control valve produced by Shanghai Automation Instrumentation Co., Ltd. No. 7 Automation Instrumentation Factory, is usually composed of electric actuators or pneumatic actuators and body parts of the two components. Straight-through travels are available in both single-seater and two-seater, which has the characteristics of large circulation capacity, unbalanced operation and stable operation, so it is usually especially suitable for large flow, high pressure drop and less leakage. Corner travel are: V-type electric control ball valve, pneumatic film shut-off valve, eccentric butterfly valve.

SHANGHAI AUTOMATION INSTRUMENTATION CO. LTD.

NO. 7 AUTOMATION INSTRUMENTATION FACTORY

Shanghai Yi Electric Actuator

SHANGYI ELECTRIC ACTUATOR

SHANGYI BRAND

SHANGHAI ROTORK CONTROL ACTUATOR

Introduction

Pneumatic sleeve control valve type according to the purpose and function, the main parameters, pressure, medium working temperature, special purpose (ie, special, special valve), drive energy, structure, etc. were classified, the most commonly used classification is Regulating valve is divided into nine categories, six for the straight trip, three for the angular travel.

classification

Classification by purpose and function

a. Two-position valve: mainly used to close or connect the media;

b. regulating valve: mainly used to adjust the system. When selecting the valve, it is necessary to determine the flow characteristics of the control valve.

c. diverter valve: for the distribution or mixing of media;

d. Shut-off valve: usually refers to the leakage rate of less than one hundred thousandth of the valve.

Sort by main parameters

1 Press the pressure classification

(1) vacuum valve: working pressure lower than the standard atmospheric pressure;

(2) low pressure valve: nominal pressure PN ≤ 1.6MPa;

(3) medium pressure valve: PN2.5 ~ 6.4MPa;

(4) high pressure valve: PNl0.0 ~ 80.OMPa, usually PN22, PN32;

(5) ultra-high pressure valve: PN ≥ IOOMPa.

2 according to the media operating temperature classification

(1) high temperature valve: t> 450 ℃;

(2) temperature valve: 220 ℃ ≤ t ≤ 450 ℃;

(3) room temperature valve: -40 ℃ ≤ t ≤ 220 ℃; ④ low temperature valve: -200 ℃ ≤ t ≤ -40 ℃.

Common classification method

This classification method is not only the principle, the role of structure by division, is the current domestic and international most commonly used classification method. Generally divided into nine categories:

(1) single seat control valve;

(2) two-seat control valve;

(3) Sleeve control valve;

(4) angle control valve;

(5) three-way control valve;

(6) Diaphragm valve;

(7) butterfly valve;

(8) ball valve;

(9) eccentric rotary valve. The first six kinds of straight trip, the latter three for the angular travel.

These nine products are also the most basic products, also known as ordinary products, basic products or standard products. A variety of special products, special products are in the nine categories of products based on improved variants out.

According to the main special purpose to points (that is, special, special valve)

(1) soft seal shut-off valve;

(2) hard seal shut-off valve;

(3) wear-resistant control valve;

(4) corrosion-resistant control valve;

(5) full tetrafluoride corrosion control valve

(6) full corrosion resistant alloy control valve;

(7) emergency action cut off or vent valve;

(8) anti-blocking control valve;

(9) corrosion resistant anti-blocking shut-off valve;

(10) insulation jacket valve;

(11) large pressure drop shutoff valve;

(12) small flow control valve;

(13) large diameter control valve;

(14) adjustable adjustment valve;

(15) low S energy saving control valve;

(16) low noise valve;

(17) fine small control valve;

(18) Lining (rubber, PTFE, ceramic) Regulating valve;

(19) Water treatment special ball valve;

(20) caustic soda special valve;

(21) Ammonium phosphate special valves;

(22) chlorine control valve;

(23) Bellows Seal Valve ...

By driving the energy classification

(3) hydraulic control valve.

Adjustment valve CV value (flow coefficient)

Flow capacity Cv value (flow coefficient) is one of the main parameters of the valve selection, the control valve flow capacity is defined as: when the control valve is fully open, the valve pressure at both ends of 0.1MPa, fluid density of 1g / cm3 , The flow rate of the flow control valve per hour, called the flow capacity, also known as the flow coefficient, expressed in Cv, the unit is t / h, the liquid Cv value calculated by the following formula.

According to the size of the circulation capacity of the Cv value of the table, you can determine the nominal diameter of the valve DN.

Regulating valve flow characteristics

The flow characteristics of the control valve are the relationship between the relative flow of the medium flowing through the control valve and its opening at the constant pressure differential across the valve. The flow characteristics of the control valve are linear, such as percentage characteristics and parabolic characteristics. The significance of the three fluence characteristics is as follows:

(1) Equal percentage characteristics (logarithmic)

The relative travel of the percent characteristic is not in a straight line relationship. The change in the flow rate caused by the change of the unit stroke at each point of the stroke is proportional to the flow rate at this point and the percentage of the flow rate change is equal. So it has the advantage of small flow, flow changes, flow is large, the flow changes, that is, in different degrees of opening, with the same adjustment accuracy.

(2) Linearity (linear)

The relative travel of the linearity characteristic is linear with the relative flow. The change in the flow caused by changes in the unit travel is constant. When the flow rate is large, the relative value of flow change is small, and when the flow rate is small, the relative value of flow changes greatly.

(3) parabolic characteristics

The flow rate varies in proportion to the two sides of the stroke, which generally have intermediate characteristics of linearity and equal percentage characteristics.

From the analysis of the above three characteristics can be seen, on its regulation performance speaking, to equal percentage of the characteristics of the best, its regulation is stable, good regulation. The parabolic characteristics and better than the linear characteristics of the regulatory performance, according to the requirements of different occasions, the selection of any one of the flow characteristics.

According to the purpose and function, the main parameters, pressure, medium working temperature, special purpose (special valve), drive energy, structure, etc. are classified, the most commonly used classification is the structure will be divided into nine Large class, six kinds of straight trip, three for the angular travel.

Control valve use and maintenance and troubleshooting methods

1, installation

Regulating valve installation does not meet the requirements of the failure will cause a huge waste, on the contrary, the installation properly, to ensure normal start and extend the service life. Reduce maintenance workload and achieve good system control performance.

(1) the installation of control valve in general should consider the following aspects:

① safety: the installation process of personnel and equipment security.

② control performance: piping system pressure loss should be calculated when the size of the valve to consider the same pressure to ensure that the required flow characteristics. Import and export should try to ensure adequate straight pipe.

③ installation location: there should be enough space for the operator to manually operate (including bypass operation) and to ensure that the control valve and accessories on the spot removal and maintenance of the possibility.

④ control valve group: generally in the process piping are installed shut-off valve bypass valve and control valve into a valve group to meet the needs of continuous operation of equipment. Check the valve with a shut-off valve. Adjust with bypass valve.