An emergency trip manifold for a turbine or other piece of industrial equipment is shown and described. More specifically, the trip manifold provides a compact design with multiple pressure readings of multiple sources. Pressure transmitters may be removed or serviced while the system is still operating. The disclosed manifold replaces the cumbersome emergency tripping systems currently used with industrial turbines and other devices where it is imperative to keep certain pressure readings, such as bearing oil pressures, thrust bearing oil pressures, condenser vacuum pressures and/or exhaust pressures within a certain predetermined range.
Emergency tripping systems have long been utilized to shut off industrial turbines in the event certain operating conditions occur. Such tripping systems are commonly designed around certain pressure readings. Those pressure readings, and the maintenance of such pressures within a prescribed range, include a pressure or vacuum reading in the condenser vacuum which is indicative of exhaust pressure, maintenance of oil bearing pressure, the prevention of an increase in the thrust bearing oil pressure and a monitoring of the autostop oil pressure. Often, the autostop oil pressure line may be in communication with a solenoid valve.
Of course, other components may form part of an emergency tripping system such as anticipator trip valves which may be tripped or activated by excessive speed of the turbine. A turbine emergency trip valve may be incorporated along with stop valve bypass trips, auxiliary pilot valve trips, lock out sleeve trips and other emergency trip functions, depending upon the manufacturer. Those skilled in the art and familiar with the turbine designs of Westinghouse and General Electric will be familiar with various trip functions associated with these turbines.
One problem associated with emergency tripping systems for industrial turbines, engines and other similar apparatuses is the cumbersome design of such systems. Specifically, piping must be provided for each pressure sensing function which is then connected to a separate transmitter. Often, it is desirable to use redundant transmitters to monitor each trip function. Specifically, transmitters are prone to failure and require frequent maintenance. Manufacturers therefore often utilize two or three transmitters to monitor one trip function with the criteria that at least two of the transmitters must register an alarm status before a shut down procedure is begun.
With the common use of multiple redundant transmitters or multiple redundant distributed control system (DCS) inputs for each trip function, the piping, wiring and mounting for the various trip functions becomes cumbersome to install and difficult to maintain. Specifically, typical systems include multiple manifolds with custom mounts that are interconnected with extensive quantities of tubing and pipe. Still further, due to the cumbersome design of these systems, there is no easy way to gain access to the transmitters or valves for service and maintenance. Thus, an improved emergency tripping system for turbines and other industrial apparatuses is needed that is less cumbersome, reliable and easy to install and maintain.
In accordance with the aforenoted needs, an improved trip manifold is disclosed which comprises a manifold body connected to a stationary header shaft. The header shaft passes through a plurality of rotary valves. Each of the rotary valves is connected to a pressure transmitter. The header shaft includes two passages including a transmitter input passage and a drain passage. The rotary valves each comprise a through passage directed towards the pressure transmitter. The manifold body provides fluid communication between an input source and the transmitter input passage of the header shaft. The manifold also provides communication between the drain passage of the header shaft and a drain vent or pressure dump. The rotary valves are each independently rotatable between two positions including a transmit position where the through passage of each valve provides communication between the transmitter input passage of the header shaft and the respective pressure transmitters and a drain position where the through passage of each valve is in communication with the drain passage of the header shaft.
In the transmit position, fluid communication is provided by the manifold and header shaft between the input source and the pressure transmitter. In the drain position, the transmitter is isolated and pressure is released from the valve to the drain vent. Thus, in the drain position, the transmitter may be safely removed and examined for service, maintenance or possible replacing. By providing multiple valves and transmitters on a header shaft, multiple redundancy pressure transmitters may be provided for a single input source. Because each valve and transmitter can be rotated to the drain position without interfering with the function of the other valves and transmitters, a single valve and transmitter can be moved to the drain position to release pressure within the valve and the transmitter can be safely removed, serviced and maintained or replaced without interfering with the operation of the other valves and transmitters. In this manner, a transmitter may be replaced without interfering with the operation of the remaining components of the manifold and therefore the turbine, engine or other apparatus being monitored may continue to run or stay on-line while a transmitter is replaced or serviced. In a preferred embodiment, three valves and three transmitters are disposed on the header shaft for each transmitter input passage and drain passage.
In one embodiment, the header shaft includes two sets of transmitter input passages and drain passages. In this embodiment, each set of transmitter input passages and drain passages extend along a different section of the header shaft. Specifically, one set of a transmitter input passage and drain passage extend axially along the header shaft from one end of the header shaft and the other set of the transmitter input passage and drain passage extend axially along the header shaft from the other end of the header shaft. In this way, the header shaft is divided into two parts, with one set of rotary valves and transmitters disposed on one part or one half of the header shaft and another set of rotary valves and transmitters disposed on the other part or other half of the header shaft. Thus, in this embodiment, one header shaft provides input communication to two different sets of valves and transmitters and also provides a drain function for each set of valves and transmitters.
In another preferred embodiment, the manifold includes a second header shaft disposed parallel to and either above or below the first header shaft. Similar or identical to the design of the first header shaft, the second header shaft also passes through a plurality of rotary valves and, most preferably, two sets of rotary valves. Therefore, the second header shaft preferably includes two sets of passages with each set including a transmitter input passage and a drain passage. In this preferred embodiment, four inputs may be monitored by the single manifold with a double or triple redundancy.
However, it may be preferable to connect the drain passages to provide a single drain passage in each header shaft.
Another option is to include a separate drain passage and separate drain for certain inputs where it is advantageous to include a separate, isolated drain. One such example is the vacuum drain of a turbine.
In another refinement, the manifold body is connected to a pair of parallel and spaced apart support blocks. The support blocks are, in turn, connected to and support the header shaft(s). The support blocks also include passages or routing to provide communication between the various inputs and the transmitted input passages of the header shafts and between the drain and the drain passages of the header shafts. The support blocks also provide a convenient place to mount gauges or connections for gauges. Of course, gauges may also be mounted to the manifold body.
Therefore, in a preferred embodiment, the manifold body is connected to four inputs that need to be monitored and is connected to two header shafts by two support blocks. Communication is provided between the header shafts and the manifold body by the support blocks. Further, in the preferred embodiment, each header shaft provides communication to two sets of three rotary valves and pressure transmitters. Therefore, the preferred manifold design provides triple redundant monitoring of four inputs and therefore it provides communication to four sets of three rotary valves and transmitters for a total of twelve valves and twelve transmitters.
However, it will be noted that the disclosed manifold design is applicable to systems with more than four inputs or less than four inputs, such as a single input. The disclosed manifold design is also applicable to systems only requiring double redundancy or no redundancy. Further, an improved method for replacing or removing a transmitter from a system while the system is on-line is also disclosed which includes moving one of the valves to the drain position as described above.
The disclosed design is particularly adaptable to currently used Westinghouse steam turbines. However, the disclosed manifold assemblies are adaptable to other uses and therefore this disclosure is not limited to trip manifolds for steam turbines, but only to trip manifolds for industrial devices requiring emergency tripping systems.
The disclosed trip manifolds and methods of use and maintenance thereof will be described more or less diagrammatically in the accompanying drawings, wherein:
It should be understood that the drawings are not necessarily to scale and that the disclosed embodiment is illustrated in certain instances with symbols, phantom lines, diagrammatic representations and partial fragmentary views. In certain instances, details, such as connections between support blocks and the manifold body or vice versa and the various fluid pathways through the manifold body and support blocks, which are not necessary for an understanding of the disclosed embodiment or which render other details difficult to perceive, have been omitted. It should be understood, of course, that this disclosure is not limited to the particular embodiment illustrated herein.
Referring to
In the embodiment shown in
To handle the two sets of rotary valves 16, 17 and transmitters 18, 19 associated with each header shaft 14, 15, each header shaft 14, 15 includes two sets of passages including the transmitter input passages shown at 21a, 21b, 22a, 22b and the drain passages shown at 23a, 23b, 24a, 24b. In an embodiment, the drain passages 23a, 23b may be connected together and the drain passages 24a, 24b may be connected together as shown in phantom in
Referring to
In contrast, in
Also shown in
Turning to
Specifically, referring first to the bearing oil input 47 (
Still referring to header shaft 14 and
Turning now to the header shaft 15, as shown in
Referring now to the autostop input shown at 44 in
Therefore, a simple, compact assembly 10 is provided which enables double triple redundancy monitoring of one to four or more different inputs. In this case, triple redundancy may be provided for thrust bearing oil pressure, bearing oil pressure, condenser vacuum pressure and autostop oil pressure. Of course, the design can be modified to provide triple redundancy monitoring for four different inputs and the design can be further modified by providing no redundancy or double redundancy monitoring of less than or more than four inputs. The manifold assembly 10, while clearly applicable to steam turbines, is also applicable to other industrial devices that require monitoring for operation safety.
While only a single preferred embodiment has been described in the figures, alternative embodiments and various modifications will be apparent from the above descriptions of those skilled in the art. These and other alternatives are considered equivalents and within the spirit and scope of this disclosure.