Adjustable self operated steam pressure reducing valve

1、 Product Description:

LKZZYP-16PAdjustable self operated steam pressure reducing valveAutomatic control valve used for pressure reduction and stabilization after gas, liquid, and steam medium valves or for pressure stabilization before valve leakage. For liquids, vapors, non corrosive gases, and low viscosity liquids with nominal diameter ≤ DN100, P1 ≤ 1.0MPa, P2 ≥ 15KPa, pressure reduction ratio ≤ 10, ≥ 1.25.Without the need for external energy, using the energy of the regulated medium itself as a power source, introducing an actuator to control the position of the valve core, changing the pressure difference and flow rate at both ends, and stabilizing the pressure before (or after) the valve. It has the advantages of sensitive action, good sealing, and small pressure set point fluctuations, and is widely used in automatic control of pressure reduction and stabilization or leakage stabilization of gas, liquid, and steam media.

Determination of pressure regulation range: The pressure regulation range is segmented, as shown in the main parameters and performance indicators table. The control pressure should be selected as close as possible to the middle value of the regulation range.

LKZZYP-16P Adjustable TypeSelf operated steam pressure reducing valveThe relationship between the pre valve pressure and the post valve pressure of the pressure regulating valve: The self operated regulating valve itself is a regulating system, and the valve itself has certain pressure drop requirements. For the post valve pressure regulating valve (type B), in order to ensure that the post valve pressure is within a certain range, the pre valve pressure must reach a certain value.

2、 Technical parameters:

Packing: Fluorotetrafluoroethylene

Type: single seat, double seat

Nominal diameter: DN20-DN300

Nominal pressure: ANSI150, 300, 600LB

JIS10、16、20、30、40K

PN1.6、2.5、4.0、6.4MPa

Connection method: Flanges: FF, RF, RJ, and LG

Flange standards: ANSI B16.5, JIS B2201

JB/T79.1 PN1.6MPa,JB/T79.2

Threads: DIN, NPT, RC, BSP, G, etc

Welding: GB12224-89

Sealing surface form: PN16 convex surface, PN40, PN63, PN100 concave surface

Material: WCB, WCC, WC6, 304, 316, 304L, 316L

Upper valve cover: standard type (-20 ℃~+200 ℃)

Low temperature type (-60 ℃~-196 ℃)

Heat dissipation type (-40 ℃~450 ℃)

Bellows sealed type

Cover type: pressure plate type

Packing: V-type PTFE, flexible graphite

Valve components:

Valve core form: single seat plunger type, pressure balanced type, double seat, metal seal, soft seal, quick opening characteristic

Valve core and seat: 304, 316, 316L+STL

Executing Agency:

Form: Multi spring thin film actuator, piston actuator

Membrane material: Rubber clip reinforced polyester fabric

Signal interface: Internal thread M16 × 1.5

Performance:

Rated KV value: refer to the table

Traffic characteristics: fast opening

Function mode: Pre valve pressure control

Post valve pressure control

Pressure regulation range: refer to the table

Pressure control accuracy: ± 8%

Leakage level: Metal seal: less than 0.01 (ANSI B16.104-1976IV level)

Soft seal: less than 0.00001%

Dimensional drawing:

Principle and Installation

1. Valve body; 2. Valve seat 3. Valve core; 4. Take over; 5. Pressure regulating disc; 6. Bellows; 7. Condenser; 8. Valve stem; 9. Spring; 10. Pressure conduit; 11. Check the execution machine

Pressure reducing type: a pressure regulating valve used to control the pressure behind the valve, and the valve operates in a pressure closed manner. The medium flows into the valve body from the front of the valve, and is output after being throttled by the valve core and seat. The other route passes through the pressure tube and condenser (used when the medium is steam) for cooling, and is introduced into the actuator to act on the effective area of the diaphragm, generating a downward force that compresses the spring, pushes the valve stem, drives the valve core displacement, and changes the flow area. To achieve the purpose of pressure reduction and stabilization. If the pressure behind the valve increases, the force acting on the effective area of the diaphragm increases, compressing the spring and driving the valve core, reducing the valve opening until the pressure behind the valve drops to the set value. Similarly, if the pressure behind the valve decreases, the force acting on the effective area of the diaphragm decreases. Under the elastic force of the spring, the valve core is driven to increase the valve opening until the pressure behind the valve rises to the set value.

Installation method:

When used in gas or low viscosity liquid media at room temperature (≤ 70 ℃), it is installed upright on a horizontal pipeline, similar to the usual pneumatic thin film regulating valve,

Note: 1. Stop valve 2. Pressure gauge 3. Filter 4. Pressure regulating valve 5. Pressure gauge

2. When the medium is steam, the pressure regulating valve needs to be installed upside down on a horizontal pipeline

Note: 1. Stop valve 2. Pressure gauge 3. Filter 4. Condenser 5. Pressure regulating valve 6. Pressure gauge

3、 The following parameters should be provided when placing an order:

(1) Valve model

(2) Nominal diameter x valve seat diameter

(3) Nominal pressure and flange connection form

(4) Valve body and internal material

(5) Upper valve cover form

(6) Traffic characteristics

(7) Form of executing agency

(8) Valve action type (gas closed, gas open or holding position)

(9) Accessories (locator, handwheel mechanism, solenoid valve, limit switch, holding valve, air filter pressure reducer, etc.)

(10) Special requirements (prohibition of oil, prohibition of copper, etc.)

(11) Media name

(12) Normal traffic, high traffic, andlow flow

(13) Medium high flow rate andThe inlet/outlet pressure corresponding to low flow rate

(14) Medium temperature

(15) Medium viscosity (whether it contains a suspension)

(16) Other requirements

4、 Reference for the impact of valve internals on noise during selection:

1. The valve noise generated by valve internals is caused by one of the following reasons:

(1) Mechanical vibration;

(2) Natural frequency vibration;

(3) Unstable throttling;

(4) The aerodynamic effects of liquid cavitation or gas flow on air flow in flowing media;

(5) Water hammer impact on valve closure components.

2. Mechanical vibration can be reduced by the following methods:

(1) Maintain a tight radial clearance;

(2) Using heavy-duty guidance to disperse impact and reduce vibration;

(3) Select heat-resistant and wear-resistant materials to prevent gap expansion;

(4) A damping ring made of elastic material is used on the heavy-duty spool guide of the sleeve valve, which can also be used as a pressure balanced sleeve structure seal.

3. The natural frequency vibration can be eliminated by the following methods:

(1) Using integral cast valve cores and components to break their symmetry, instead of welding cylindrical thin-walled tubes onto the valve stem;

(2) Replace the cylindrical thin-walled window type valve core with a plunger type valve core, or vice versa;

(3) Change the flow;

(4) Change the diameter of the valve stem;

(5) Adopting a single seat valve with heavy-duty valve core guidance (without guide rod), as the larger valve core rigidity is less sensitive to vibration.

Throttle instability refers to the vertical oscillation motion of a composite component, including the valve core, valve stem, and movable actuator components. Both single seat and double seat valves with no pressure balance are unstable. When their throttling reaches high pressure and the stroke is reduced, as explained in the "Fluid Dynamic Effects" section, a huge upward and downward thrust is generated by the fluid colliding with the valve core, rapidly changing their direction and amplitude. This impact may be amplified by actuators with valve positioners, and their combined frequency characteristics may lose the required control effect. So, it caused pressure fluctuations in the flowing medium, producing a rumbling noise with a frequency of about 30 Hz. The vibration depends on the rigidity of movable parts such as the valve core, valve stem, and actuator, as well as the stiffness of the spring. The valve seat, valve core, and valve stem may be damaged due to leakage or valve stem fracture caused by vibration. In addition, the wear rate of the valve stem packing will also increase.

4. The instability of throttling can be reduced by the following methods:

(1) Use actuators with high rigidity (high spring range);

(2) Install a pulse damper, or use a "hydraulic buffer" to install it on the push rod of the actuator;

(3) Design a pressure balanced sleeve to reduce the amplitude of unbalanced forces, thereby improving stability;

(4) Maintain fast frequency response for the combination of regulator valve positioner actuator.

5. The noise of flowing media includes:

(1) Cavitation noise refers to the noise generated by the rupture and impact of bubbles formed through the annular gap between the valve seat and the valve core under high pressure drop;

(2) Aerodynamic noise, caused by the flow of high-pressure gas into and out of valves, is a huge noise. Aerodynamic noise may also generate sound shock waves due to pressure recovery and subsequent decrease in flow velocity in downstream channels.