Abstract:
A transfer valve system includes an improved double block and bleed transflow valve system which uses six valves and uses one single spindle interconnecting the inlet and outlet transflow valves, which valves also drive a gear train mechanism connecting all six valve stems. As such, by operating one main spindle connected to the two inlet and outlet transflow valves, all six valves of this double block and bleed configuration operate simultaneously and assure an uninterrupted flow of fluid from one device to another standby device. The transflow valve system also is formed of separable components to form both single and double block and bleed configurations.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application asserts priority from provisional application 61/787,110 filed on Mar. 15, 2013, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a transflow valve forming part of a bearing or mechanical seal support system or other support system for turbomachinery, and more particularly, to an isolation and switching mechanism for a transflow valve for such support systems. 
     BACKGROUND OF THE INVENTION 
     Bearing and mechanical seal support systems or other support systems for turbomachinery often may use fluid flow systems, which use various system devices to control the flow of a fluid, such as a gas or liquid through the support systems. The fluid flows through an operational system device but is switchable by a transflow valve to a standby system device. The fluid flow systems include a variety of fluid handling or transfer valves, which define independent fluid flow lines having flow passages through which flow is directed, controlled and in many cases diverted from one independent flow line to another fluid flow line. These fluid flow systems can include a variety of system components and devices that are used in a variety of different applications. For example, such system devices may include process filters, seal gas filters, fuel gas filters, lube oil filters, seal oil systems, scrubbers, gas-liquid separators, heat exchangers (cooling or heating) and gas or oil heaters used in any industry application. Accordingly, such devices are used with the bearing or mechanical seal support systems for turbomachinery where continuous and uninterrupted supply of a gas or liquid is needed for the main equipment and system. 
     In such applications, it is desirable for continuous fluid flow through the system, such that when one system device is spent or requires maintenance, another standby device can be brought on-line immediately so that the entire system need not be shut down. In one example, a fluid delivery system used for pumps, compressors or other types of rotating equipment for fluid delivery will include mechanical seals on the rotating equipment to seal such equipment, which seals are supplied with dry gas such as a barrier or buffer fluid in a conventional manner. It is necessary to continuously supply such gas during operation of the rotating equipment, wherein such gas will pass through the system devices, such as seal gas filters, that are provided in the gas supply system. 
     Thus, multiple or redundant system devices, such as gas seal filters, may be placed adjacent to one another, with at least one of the system devices being shutoff from the system, i.e. on standby, while at least one other system device is being used, i.e. is operational. Such a set-up allows a user or automated system to select which of the system devices are to be used at a certain time as the operational device and which devices are not to be used so as to serve as the standby device. Once an operational system device is spent or requires servicing, the operational device is shutoff from the system for replacement or maintenance and the standby device is put on line in its place. 
     To affect shutoff or switching between fluid treatment devices, transflow valves are used to isolate and switchover the system devices so that fluid flow switches from the operational device to the standby device. 
     Conventional transflow valves can be constructed using three way ball valves such as that shown in  FIG. 1  which are provided with one common spindle to operate the flow through the inlet and outlet sections of the transflow valves together in unison. Generally, there are two types of transflow valves used in industry, wherein one is a single block and bleed (SBB) valve ( FIG. 1 ) and another one is a double block and bleed (DBB) valve ( FIG. 2 ). The SBB transflow valve of  FIG. 1  has one common spindle CS- 1  connected to valve stems of an inlet transflow valve V 1 - 1  and an outlet transflow valve V 2 - 1 . The DBB transflow valve of  FIG. 2  has three valve spindles CS 1 , CS 2 , and CS 3  linked together by a common handle assembly HL- 2  to operate six transflow valves through one single operation. 
     More particularly,  FIG. 1  is a schematic of a single block and bleed (SBB) transflow valve currently used in industry. In this drawing, A represents the equipment in operation, i.e. the operational device, and B represents the equipment in standby mode, i.e. the standby device. Each device has a vent and drain and is supplied by a respective inlet and outlet which are controlled through the valves V 1 - 1  and V 2 - 1 , which in turn are connected to the main INLET or OUTLET. The valves V 1 - 1  and V 2 - 1  have respective valve stems connected to the common spindle CS- 1  which is rotated manually by the handle HL- 1 . 
     The inlet and outlet for device A respectively have bleed valves B 1 - 1  and B 2 - 1  connected thereto, while the inlet and outlet for device B have respective bleed valves B 3 - 1  and B 4 - 1  connected thereto. A pressure equalizing valve E is also provided. Rotation of the spindle CS- 1  by the handle HL- 1  simultaneously switches the inlet and outlet transflow valves V 1 - 1  and V 2 - 1  between devices A and B. Hence, a fluid supply connected to device A is isolated from device B based on the valve position for valves V 1 - 1  and V 2 - 1 , but the fluid supply can be switched over to device B and shut off from device A without affecting the flow to the devices downstream of the SBB transflow valve. Using valves V 1 - 1  and V 2 - 2  by operating the common spindle (CS- 1 ) and the handle (HL- 1 ), the device A is in operation and device B is in standby mode. Device B can be attended to for maintenance such as changing of the filter elements if the devices A and B were gas seal filters. Prior to the maintenance, the stand by side bleed valves B 3 - 1  and B 4 - 1  are normally closed but then opened to depressurize the device vessel  2  for safety prior to maintenance. By operating the valve position, the flow can be changed to switchover the flow to device B while device A becomes the standby device. 
     In the DBB transflow valve of  FIG. 2 , this also is a known device used in industry. Here again, A represents the equipment in operation and B represents the equipment in standby mode. This valve configuration uses a first block valve comprising inlet and outlet transflow valves V 1 - 2  and V 2 - 2 , and a second block valve comprising inlet valves V 3 - 2 , V 4 - 2  and outlet valves V 5 - 2  and V 6 - 2 . These valves are connected in pairs by common spindles CS 1 , CS 2  and CS 3  which are all connected by handle linkage LK- 2  operated by handle HL- 2 . Manual rotation of the handle HL- 2  rotates the common spindles CS 1 , CS 2  and CS 3  through linkage LK- 2  which in turn opens and closes the appropriate transflow valves. In this regard, the fluid supply may be connected to device A and isolated from device B based on the valve position for interconnected valve pairs V 1 - 2 /V 2 - 2 , V 3 - 2 /V 5 - 2 , and V 4 - 2 /V 6 - 2 . The fluid supply can be switched over to device B without affecting the flow to the devices downstream of the transflow valve assembly. 
     Therefore, main inlet and outlet valves V 1 - 2  and V 2 - 2  of the first block valve define the main switchover valve for diverting the fluid flow direction towards devices A or B, while the inlet and outlet valves V 3 - 2  and V 5 - 2  define the second block valve for device A and inlet and outlet valves V 4 - 2  and V 6 - 2  define the second block valve for device B. By operating the handle HL- 2 , all of these six valves are operated simultaneously. Notably, valves B 1 - 2 , B 2 - 2 , B 3 - 2 , B 4 - 2 , B 5 - 2 , B 6 - 2 , B 7 - 2  and B 8 - 2  are bleed valves, which are normally closed and selectively opened to depressurize the devices A or B during maintenance. 
     In another commercial design of a transflow valve for a double block and bleed (DBB) application ( FIG. 3 ), this design is based on using a SBB design for first block valves (V 1 - 3  and V 2 - 3 ), which are connected by a common spindle CS and operated by a handle HL like in  FIG. 1 . This design uses separate second block valves (V 3 - 3 , V 4 - 3 , V 5 - 3  and V 6 - 3 ), which are independent valves operated by their own respective handle H 3 , H 4 , H 5  and H 6 . B 1 - 3 , B 2 - 3 , B 3 - 3 , B 4 - 3 , B 5 - 3 , B 6 - 3 , B 7 - 3  and B 8 - 3  are bleed valves, which are normally closed and selectively opened to depressurize devices A or B during maintenance. 
     In operation, if any one of these transflow valves (V 3 - 3 , V 4 - 3 , V 5 - 3  and V 6 - 3 ) are operated incorrectly by being closed when it should be open, the process device A or B will lose the supply of fluid or may allow the fluid flow to flow in the wrong direction and cause an operational issue and unsafe maintenance. This arrangement depends on the skill set of the operator and a thorough understanding of the valves positions by the operators. Hence, this design is not a fool proof device and depends on the operator&#39;s skill and care. 
     It is an object of the invention to provide an improved transflow valve assembly, which overcomes disadvantages associated with known transflow valve designs. 
     The invention relates to an improved double block and bleed transflow valve which uses one single spindle interconnecting the inlet and outlet transflow valves with which valves also drive a gear train mechanism connecting all six valve stems. As such, by operating one main spindle connected to the two inlet and outlet transflow valves, all six valves of this double block and bleed configuration operate simultaneously through the common spindle and gear train mechanism and assure an uninterrupted flow of fluid from one device to another standby device. 
     Generally, the preferred design of the present invention includes two system devices and in particular, two fluid treatment devices such as gas seal filters, where inlet and outlet flow to and from the filters is controlled by respective inlet and outlet transfer valves, which selectively switch or transfer fluid flow from one filter to another. These system devices may be any type of such devices used with transflow valves, and it will be understood that the fluid transfer valves disclosed herein are usable with various types of turbomachinery devices which receive and transfer fluid that flows therethrough. For example, the inventive fluid transfer valves can be provided on the upstream and downstream sides of one or more fluid handling or flow devices to selectively switch or transfer flow of fluid from one device to the other. 
     Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         FIG. 1  is a schematic diagram of a single block and bleed transflow valve system. 
         FIG. 2  is a schematic diagram of a double block and bleed transflow valve system. 
         FIG. 3  is a schematic view of a further embodiment of a double block and bleed transflow valve system. 
         FIG. 4  is a schematic diagram of a double block and bleed transflow valve system, according to the present invention. 
         FIG. 5  is a detailed view thereof. 
         FIG. 6  is a enlarged partial view thereof. 
         FIG. 7  illustrates a first step in modifying the system, according to a modular construction thereof. 
         FIG. 8  shows a second step of the system modification. 
     
    
    
     Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “up”, “down”, “right” and left” will designate directions in the drawings to which reference is made. The words “in” and “out” will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. The words “proximal” and “distal” will refer to the orientation of an element with respect to the device. Such terminology will include derivatives and words of similar import. 
     DETAILED DESCRIPTION 
     Referring to  FIG. 4 , a transflow valve assembly  1  of the present invention is shown in a double block and bleed configuration. As in the above figures, A represents the operational device and B represents the standby device wherein the devices A and B are connected to the transflow valve assembly  1  by respective pipe fittings  2 . As will be described herein, these devices A and B are switchable in response to operation of the transflow valve assembly  1  of the present invention. 
     The inventive transflow valve assembly  1  is connected between devices A and B and is connected so as to receive system fluid through the inlet  3  and discharge such fluid to the outlet  4 . In this double block and bleed configuration, a first pair of transflow valves  5  and  6  are provided, which are inter connected by a common spindle. These valves  5  and  6  may be ball valves or other suitable valves. Spindle  13  is rotatable manually by the handle  14 . Therefore, manual rotation of the handle  14  rotates the spindle  13  which in turn drives the valve stems  9  of the transflow valves  5  and  6 . Hence, these transflow valves  5  and  6  are movable, simultaneously to either direct flow of fluid into and out of the device A or else into in and out of device B.  FIG. 5  illustrates the open condition of the valves  5  and  6  in white, while showing the closed passage side in dark shading or cross-hatching. It will be understood that the white and black representations are reversible when the valve is operated to change flow from device A and instead direct flow to device B. 
     These valves  5  and  6  also may be referenced as the main diverter valves for the fluid flow direction, which control the flow of the fluid either towards device A or towards device B. 
     Additionally, a set of block valves are provided in the double block configuration. As shown in this regard, a pair of block valves  7  are connected to one down-stream side of the diverter valves  5  and  6  and in turn connected to the device A as the inlet and outlet thereof. Appropriate bleed valves  15  and  16  are provided to release pressure there from and during maintenance. 
     A second pair of block valves  8  is also provided on the second side of the diverter valves  5  and  6  so as to control flow into and out of the device B. Additional bleed valves  15  and  16  are also provided in association with these block valves  8 . To simultaneously drive all of the valves  5 - 8 , the diverter valves  5  and  6  have their valve stems  9  ( FIG. 5 ) each drivingly inter-connected with drive-gears  11 , which drive-gears  11  are operatively connected to the spindle  13 . Hence, rotation of the spindle  13  by the handle  14  also causes simultaneous rotation of the drive gears  11  about the axis of such spindle  13 . 
     These gears  11  have gear teeth, which intermesh with additional driven gears  12  that are interconnected to the valve stems  10  ( FIG. 5 ) of the block valves  7  and  8 . Preferably, these gears  11  and  12  are spur gears, having intermeshing gear teeth. In this regard, one set of valves  6 ,  7  and  8  on the inlet side of the transflow valve assembly would be simultaneously driven by their respective drive gear  11  and driven gears  12  during rotation of the spindle  13 . Similarly, the valves  6 ,  7  and  8  on the outlet side are also simultaneously operated by the inter-meshed gears  11  and  12  connected thereto. Therefore, operation of the handle  14 , rotates the spindle  13  and transmits rotary motion to each set or gear set of gears  11  and  12 , either on the inlet side or the outlet side, so as to turn the valve stems  9  and  10  and operate all six of the respective valves  5 ,  6 ,  7  and  8 . With this arrangement, the two gear trains are operated by a single common spindle  13 , and the one common spindle  13  and handle  14  enables operation of all six valves  5 - 8  simultaneously so that the flow of fluid changes from device A to device B or device B to device A, without interruption. 
     Referring to  FIGS. 5 and 6 , the transflow valves  5 ,  6 ,  7  and  8  are formed as modular blocks or modules, which are connected together by suitable fasteners. In the double block and bleed configuration of  FIGS. 5 and 6 , a first valve  5  or  6  is positioned between a respective pair of inlet or outlet valves  7  and  8  so that the valve flow paths flow either to the pipe fittings  2  connected to the device A or the pipe fittings  2  connected to the device B. By the provision of these six (6) valves, the flow can be directed either through the valves  7  or valves  8  in the same manner as described herein. Referring to  FIG. 7 , however, these same components may also be used to form a single block and bleed configuration. In this regard, the valve modules for valves  7  and  8  are omitted and only the central assembly, comprising the valves  5  and  6  is provided between the devices A and B. The pipe fittings  2  are then respectively connected to the opposite sides of the valve modules  5  and  6  and when interconnected, form the single block and bleed configuration seen in  FIG. 8 . In this construction, the central drive gears  11  can be removed from the valve stems  9  prior to installation of the spindle  13 . Once assembled, the spindle  13  drives the valve stems  9  for each of the valves  5  and  6  to alternate operation between devices A and B. Hence, the same components may be used to form both of the valve configurations shown in  FIGS. 5 and 8 . 
     Referring to  FIG. 5 , a modular construction for the transflow valve assembly  1  comprises the six block valves  5 ,  6 ,  7  and  8 , which control the inlet and outlet sides. Each valve  5 ,  6 ,  7  and  8  is formed as a valve module, which each have a modular construction and are removably engagable with each other by fasteners. These modules are used to build both a single block and bleed configuration SBB ( FIG. 8 ) or a double block and bleed configuration DBB ( FIGS. 5 and 6 ) from the same components. 
     In  FIGS. 5-8 , items  3  and  4  are the inlet and outlet flange adapters for connection of the process piping designed according to pressure rating and line size, and items  5  and  6  are first block or transflow valves for the inlet and outlet flow switchover. Items  7  and  8  are second block valves, which can be provided as additional modules that can be used only when a DBB arrangement is required. Item  9  is the main valve stem for each valve  5  and  6  wherein both of these stems  9  are connected together by spindle  13 . Also, a drive gear  11  is installed on each valve stem  9  while the spindle is operated by handle  14  to rotate the valve stems  9  and actuate the valves  5  and  6 . 
     Items  7  and  8  are block valves having basically the same design except that they are formed with a mirror image  7  for the left side and  8  for the right side. Item  10  is the valve stem for each valve  7  and  8 , which are each equipped with a driven gear  12 . The driven gear  12  is engaged with drive gear  11  constantly, and when the main handle  14  is operated between 0 to 90° (a one quarter turn), each drive gear  11  drives the respective driven gears  12  on both the left and right side through the same angle but in the opposite direction. Thus when the switchover or diverter valves  5  and  6  are operated, the second block valves  7  and  8  are operated. 
     As noted above, items  15  are first stage bleed valves and items  16  are second stage bleed valves. These bleed valves are used for venting the system for maintenance or purging purpose. This modular design allows for construction of the single block and bleed configuration of  FIGS. 7 and 8 . Alternatively, the same modular components may be used to construct the double block and bleed design of  FIGS. 4-6 . Further, the double block and bleed design of  FIGS. 4-6  allows a single spindle  13  to be used to drive two separate gear trains formed of three gears  12 / 11 / 12  operating three valves  7 / 6 / 8  or  7 / 5 / 8 . This provides an improved operation and construction for a double block and bleed transflow valve assembly. 
     Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.