Patent Application
20090159133
The present invention generally relates to fluid control valves and, more particularly, relates to fluid control valves adapted to harsh, high-pressure environments such as steel mills.
Steel mills produce steel from iron ore by removing impurities such as sulfur and phosphorous and adding alloying elements such as manganese, nickel, and chromium. The mills then transform the molten steel into slabs and sheets of steel through casting and rolling. After casting and prior to rolling, molten metal begins to cool, and scale formations develop on the surface of the steel. These scales or flaking must be removed prior to rolling. In descaling steel, a high pressure liquid, usually water, is directed toward the surface of the steel via a plurality of jet nozzles. Descale pumps are used to forward large volumes of pressurized water to the nozzles from a reservoir or accumulator. Descale water often contains sand, sediment, and other abrasive materials. Valves are used to turn on and off the flow of water between the pumps and the nozzles based on need.
Conventional poppet valves in this setting are constructed using an elastomeric valve seat or elastomeric gaskets around the poppet head to form a seal when the poppet head and seat are in engagement. Elastomeric materials fail rapidly because the high pressure water containing abrasive materials cuts and erodes the elastomeric material of the valves as it flows from the descale pump to the nozzles. In addition, conventional poppet valves in this setting are designed to close off this high pressure water source within one or two seconds. Conventional poppet valve systems do not control the speed at which the poppet valve opens and closes, causing the poppet head to slam into the seat. As a result of this slamming, the energy contained in the high pressure water causes system shock which propagates upstream from the valves and damages valves, pumps, piping, and related system components.
In view of the above, it is apparent that there is a need for a valve and a method of controlling said valve that is less susceptible to high pressure water containing abrasive contaminants and which produces less system shock upon opening and closing off the high pressure water source.
Accordingly, the present disclosure provides a poppet valve apparatus and method which is directed at reducing cost and wear on the descaling system.
In accordance with one aspect of the disclosure, a low viscosity, high pressure fluid control valve assembly for use in high pressure applications is disclosed which comprises a valve housing, a poppet mounted within the valve housing, a valve seat mounted in the valve body, and a servo motor. The valve housing defines a valve body, a flow inlet, and a flow outlet. The poppet within the valve housing has balancing channels to channel pressurized fluid through the poppet to allow the poppet to become pressure balanced with a hydraulic bias to be closed. The poppet is adapted to move between an open position allowing fluid communication between the inlet and outlet. The poppet further includes a valve head made of ceramic. The valve head engages the valve seat when the poppet is in the closed position. The valve seat is made of ceramic. The servo motor is operatively connected to the poppet to move the poppet between the open and closed positions.
In accordance with another aspect of the disclosure, a low viscosity, high pressure fluid control valve assembly for use in steel mill applications is disclosed which comprises a valve housing, a poppet mounted within the valve housing, a valve seat mounted in the valve body, and a servo motor. The valve housing defines a valve body, a flow inlet, and a flow outlet. The poppet within the valve housing has balancing channels to channel pressurized fluid through the poppet to allow the poppet to become pressure balanced with a hydraulic bias to be closed. The poppet is adapted to move between an open position allowing fluid communication between the inlet and outlet. The poppet further includes a valve head made of ceramic. The valve head engages the valve seat when the poppet is in the closed position. The valve seat is made of ceramic. The servo motor is operatively connected to the poppet to move the poppet between the open and closed positions.
In accordance with another aspect of the disclosure, a method for controlling a flow of high pressure fluid is disclosed which comprises providing a valve assembly consisting of a ceramic poppet valve and a ceramic valve seat, a ceramic pressure breakdown orifice pack and a header holding a plurality of spray nozzles; determining differential pressure between a flow inlet and a flow outlet; determining a fluid pressure within the poppet valve; sending signals representative of the differential pressure, fluid pressure and position to a microprocessor which controls a servo motor; calculating a servo motor position using the microprocessor's algorithm to determine the next position of the servo motor; and pre-filling of the header in order to saturate said header with water prior to the high pressure water source being opened in the circuit.
In accordance with a still further aspect of the disclosure, a low viscosity, high pressure fluid control valve assembly for use in steel mill applications is disclosed which comprises a valve housing, a poppet mounted within the valve housing, a valve seat mounted in the valve body, a servo motor, and a ceramic pressure breakdown orifice pack. The valve housing defines a valve body, a flow inlet, and a flow outlet. The poppet within the valve housing has balancing channels to channel pressurized fluid through the poppet to allow the poppet to become pressure balanced with a hydraulic bias to be closed. The poppet is adapted to move between an open position allowing fluid communication between the inlet and outlet. The poppet further includes a valve head made of ceramic. The valve head engages the valve seat when the poppet is in the closed position. The valve seat is made of ceramic. The servo motor is operatively connected to the poppet to move the poppet between the open and closed positions. The ceramic pressure breakdown orifice pack contains a series of chambers with varying diameter holes acting as orifices and ceramic plates on each side of the orifice.
These and other aspects and features of the disclosure become more apparent upon reading the following detailed description taken in conjunction with the accompanying drawings.
While the present disclosure is susceptible to various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the present invention to the specific forms disclosed, but on the contrary, the intention is to covet all modifications, alternative constructions, and equivalents falling within the spirit and scope of the present invention.
Referring again to
As shown in
Assuming the main valve 108 is not closed, high pressure fluid is received by the poppet valve assembly 66 via the flow inlet 96 and flows through the pressure reducer 44. The reduced-pressure fluid then flows out through the flow outlet 98 to the header 26. The operation of the poppet valve assembly 66 allows the poppet 74 to be opened and closed at variable rates and speeds by use of the servo motor 48 controlled electromechanical actuator.
In one embodiment, the servo motor 48 controlled electromechanical actuator proportionally closes the poppet 74 during the last stages of its closing (for example 0 5 to 1 0 seconds) to prevent slamming of the poppet 74 against the ceramic seat 80. The servo motor 48 may receive pressure and position readings via sensors (not shown) and uses these readings internally in its microprocessor (not shown) to calculate the speed at which the poppet 74 is closed against the ceramic seat 80. The servo motor 48 controls the lineal actuator 46 and gear box 52 to actuate the electromechanical actuator 50 which then moves the poppet 74 to the calculated position. In another embodiment, the servo motor may just be programmed to move at the same speed and distance with every cycle, if such values are pre-determined.
A balancing rod 54 is coupled to the electromechanical actuator 50 on one end and the poppet 74 on the other end. A seal 64 is in place at the interface between the balancing rod 54 and poppet 74. A stand 56 is provided to protect moving parts such as the balancing rod 54 and electromechanical actuator 50. A cap 58 and housing 72 are provided to seal the poppet 74 system. Beatings 68 and seals 70 are provided between the poppet 74 and the housing 72.
The poppet 74 and seat 80 are constructed of ceramic or other hardened material to utilize the wear resistance properties of these materials. By using such elements the short life span of elastomeric grommets and seals is overcome. An additional design feature of the valve 66 allows for the pressurized fluid to continually be channeled through the poppet 74 through balancing passages 76. This allows the poppet 74 to become pressure-balanced with a hydraulic bias to be closed, allowing the poppet 74 to be moved by the electromechanical actuator 50 with lower force.
Referring to
From the foregoing, it can be seen that the teachings of the disclosure can be used to manufacture an electromechanically-controlled ceramic-based proportional valve and accompanying ceramic pressure breakdown orifice pack. The invention is manufactured to withstand wear and tear in extreme high-pressure conditions such as seen in a steel mill. Because of its ability to withstand extreme conditions, the invention results in lower maintenance costs and therefore lower operating costs for its users, as well as a longer product life.
