Patent Publication Number: US-11046087-B2

Title: Vacuum operated pumps

Description:
BACKGROUND 
     Positive displacement pumps, such as vacuum operated pumps, have been used in a variety of applications, where fluid from a supply side may be provided to a receiving side. For instance, the positive displacement pumps may be used in printer systems for supplying ink to a print head assembly. Such pumps generally include an inlet port for ingress of fluid and an outlet port to discharge the fluid. To ensure that the vacuum operated pump is adequately operated and the ports work efficiently, for instance, to avoid accidental discharge from the outlet port, mechanisms to isolate the ports may be provided. For example, the inlet port and the outlet port may be isolated using additional valves, such as shut off valves. Further, such shut off valves in turn may be operated by an actuating mechanism to open and shut in accordance with the operations of the pump. 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
       The following detailed description references the drawings, wherein: 
         FIG. 1  illustrates an example block diagram representation of an apparatus implementing a vacuum operating pump, according to an example implementation of the present subject matter, 
         FIG. 2  illustrates an example block diagram representation of the vacuum operating pump, according to an example implementation of the present subject matter; 
         FIG. 3  illustrates an isometric view of the vacuum operated pump, according to an example implementation of the present subject matter; 
         FIG. 4  illustrates an exploded view of the vacuum operated pump, according to an example implementation of the present subject matter, and 
         FIG. 5-7  illustrate cross-sectional views of the vacuum operated pump in various states, according to example implementations of the present subject matter. 
     
    
    
     DETAILED DESCRIPTION 
     Pumps are generally used for moving fluids from a reservoir to a receiver. The pumps may be classified in various categories, based on principle of operation. Positive displacement pump is one such category of pumps, where fluid may be pumped with substantially the same speed regardless of pressure on an inlet end. One of commonly used positive displacement pumps are vacuum operated pumps. Generally, in vacuum operated pumps, partial vacuum is created to allow ingress and discharge of fluids. The vacuum operated pumps have been used in a variety of applications, where a fluid from a reservoir may be provided to a receiving side. Vacuum operated pumps may be used in printer systems, where ink from a reservoir may be provided to a print head assembly. 
     To prevent accidental discharge of fluid and to ensure that the vacuum operated pump operates properly the outlet port and an inlet port are often isolated using additional valves, such as shut off valves. For example, in a printer system with four color based color system, four shut off valves may be used to separate each intake port from the outlet port. Such shut off valves in turn may be operated by an actuating mechanism to open and shut in accordance with the operations of the pump. The actuating mechanism may in turn be integrated with a control unit to synchronize the functioning of the shut off valves with that of the pump. This in turn may make the pump assembly bulky, costly, resource intensive, and complex. 
     Various examples of a vacuum operated pump, and systems incorporating such vacuum pumps, are described. In an example, the vacuum operated pump may include a plurality of fluid ports, such as an inlet port and outlet port, to receive and discharge fluid. The vacuum operated pump may also include a communication port to control flow of fluid from the inlet port to the outlet port. In an open state, the communication port may allow flow of fluid from the inlet port towards the outlet; however, in a closed state, the communication port may block the flow of fluid to the outlet port, thereby isolating the two ports. 
     In one example, the fluid ports and the communication port may be controlled by a reciprocating motion of a diaphragm of the vacuum operated pump. For instance, in an idle state of the vacuum operated pump, i.e., when vacuum operated pump is not operating, the diaphragm may be in collapsed state to mate with communication port, thereby sealing the same. As a result of communication port being sealed, the fluid ports are automatically isolated to prevent flow of fluid from the inlet to outlet and subsequently to a fluid receiving unit, when the vacuum operated pump is idle. 
     During operation, on application of suction pressure, the diaphragm may expand to open the communication port and creating negative pressure in the vacuum operated pump. The negative pressure may in turn cause the inlet port to open to allow ingress of the fluid from a reservoir. As the fluid enters the pump, the negative pressure may be released through a vent, thus allowing diaphragm to move to back to original position, i.e., collapsed state. The upward motion of the diaphragm causes positive pressure to be developed again in the pump. Consequently, the outlet port may open to discharge the fluid from the pump. As the diaphragm returns to original position, i.e., collapsed state, the communication port may be sealed again, thereby separating and isolating the fluid ports. 
     Thus, the present subject matter provides a vacuum operated pump, where the reciprocating motion of the diaphragm not only controls the fluid ports for ingress and discharge of fluids but also the communication port, which in turn may provide for isolating fluid ports. As the fluid ports may now be efficiently isolated without additional valves, such as the shut off valves, the vacuum operated pump may also be free from other mechanisms associated with a shut off valve, such as an actuation mechanism for controlling the shut off valves. Consequently, the vacuum operated pump may also be free from an additional set-up used for integrating the actuation mechanism with a control unit to synchronize the functioning of the shut off valve with that of the pump. Moreover, as the communication port may block a fluid channel that may be between fluid ports, a separate shut off valve may not be installed for each inlet port. 
     Accordingly, with the communication port providing for isolation of the fluid ports and the diaphragm controlling both the fluid ports and the communication port, number of pump components may be substantially reduced, thereby making entire pump assembly cost effective and compact. Further, it will be appreciated that higher the number of components, higher the cost and the efforts in establishing the additional control mechanisms and therefore with fewer components, the vacuum operated pump of the present subject matter may be resource efficient. 
     The following detailed description refers to the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar parts. While several examples are described in the description, modifications, adaptations, and other implementations are possible. Accordingly, the following detailed description does not limit the disclosed examples. Instead, the proper scope of the disclosed examples may be defined by the appended claims. 
       FIG. 1  illustrates a block diagram of an example apparatus  100  implementing a vacuum operated pump  105 , and  FIG. 2  illustrates a block diagram of the vacuum pump  105 , according to an example implementation of the present subject matter. The apparatus  100  may be implemented a variety of systems, for instance a printer system, where ink may be provided from an ink source to a print head assembly via the vacuum operated pump  105 . 
     In an example, the apparatus may include a reservoir  110 , such as the ink source and a fluid receiving unit  115 , such as the print head assembly. The fluid from the reservoir  110  may be provided to the fluid receiving unit  115  using the vacuum operated pump  105 , hereinafter referred to as pump  105 . The pump  105 , amongst other things, may include a plurality of fluid ports  120 , such as an inlet port  120 - 1  and an outlet port  120 - 2 , a communication port  125  to provide for communication between the fluid ports  120 , and a diaphragm  130  to control opening and closing of the fluid ports  120  and the communication port  125 . 
     According to an aspect of the present subject matter, the communication port  125  is disposed in the vacuum operated pump  105  such that the fluid from the inlet port  120 - 1  may be provided to the outlet port  120 - 2  through the communication port  125 . Thus, in an open state of the communication port  125 , the fluid from the inlet port  120 - 1  may be allowed to flow to the outlet port  120 - 2 , from where it may be discharged to the fluid receiving unit  115 . 
     In an idle state of the pump  105 , i.e., when pump  105  is not operating, the diaphragm  130  may be in a collapsed state to mate or seal the communication port  125 , as explained in detail in subsequent figures. As a result of the communication port  125  being closed, the flow of the fluid to the outlet port  120 - 2  is restricted thereby isolating the outlet port  120 - 2  from the inlet port  120 - 1 . During operation or in active state, the diaphragm  130  may expand to open the communication port  125 . Further, as the communication port  125  open, the negative pressure may develop in the pump  105  causing the inlet port  120 - 1  to open to allow ingress of the fluid into a fluid chamber (illustrated in  FIG. 6 ). The negative pressure may be released after a certain time, which allows the diaphragm  130  to return to a collapsed state. This develops positive pressure in the pump  105 , thus opening the outlet port  120 - 2  for discharging the fluid. Thus, in the active state, the communication port  125  and a fluid port  120  may open and other(s) fluid ports  120  may close to provide for pumping of fluid. Details pertaining to the vacuum operated pump  105  in the idle state and in operation are discussed in detail in subsequent figures. 
       FIG. 3  illustrates an exploded view of the pump  105  and  FIG. 4  illustrates an isometric view of the pump  105 , according to example implementations of the present subject matter. For the sake of brevity, two fluid ports, the inlet fluid port  120 - 1  and the outlet fluid port  120 - 2  are illustrated; however, it will be appreciated that the pump  105  may include more than two fluid ports as well. The inlet port  120 - 1  and the outlet port  120 - 2  may be provided in a fluid injection housing  305  disposed at a first end  310  of the pump  105 . The inlet port  120 - 1  may be coupled to the reservoir  110  and the outlet port  120 - 2  may be coupled to the fluid receiving unit  115 . 
     The fluid injection housing  305  may be coupled to a valve housing  315 . The fluid injection housing  305  may be coupled via an O-ring  320  to the valve housing  315 . The valve housing  315  may include a fluid valve  325  corresponding to each of the fluid ports  120 . The fluid valve  325  may be a one-way valve to allow fluid to flow at a predetermined pressure in one direction and prevent back flow in an opposite direction. The fluid valve  325  may be, for instance, an umbrella valve, which may include an elastomeric component, such as a diaphragm to open or close the fluid valve  325  (and thus the fluid ports  120 ), based on a pressure inside the pump  105 . In an example, the predetermined pressure in the pump  105  to control the fluid ports  120  and the fluid valves  325  is controlled by a reciprocating movement of diaphragm  130 , as will be discussed in detail with reference to description of  FIGS. 5-7 . 
     Referring to the second end  330  of the pump  105 , a vacuum port  335  may be provided at the second end  330  of the pump  130 . In an example, while one end of the vacuum port  335  may be coupled to a vacuum pump (not shown in figures) to provide suction pressure, the other end, for instance, integrated with a diaphragm housing  340 . The diaphragm housing  340  may include a cavity to house the diaphragm  130  and a biasing component  345 , which may be coupled to the diaphragm  130 . The biasing component  345  may be, for instance, a compressible spring  345 - 1  coupled to the diaphragm  130  through a spring mount  345 - 2 . The biasing component  345  is disposed such that the biasing component  345  pushes the diaphragm  130  against the communication port  125 , during an idle state of the pump  105 . Thus, in the idle state, the fluid ports  120  may be isolated from each other. On the other hand, in an active state of the pump  105 , i.e., when suction pressure is applied at the vacuum port  335 , the diaphragm  130  may be pulled, thereby compressing the bias component  325 . As a result of the diaphragm  130  being pulled, the communication port  125  may open, which may provide for opening of the inlet port  120 - 1 . 
     In an example, the communication port  125  may be a port formed in a port plate  350 , which may dome shaped, i.e., in the form of a hemi-sphere so that the diaphragm  130  may easily cooperate with the port plate  350  to seal the communication port  125  in the idle state of the pump  105 . Further, in the active state, the diaphragm  130  may expand to provide for creation of the fluid chamber with a valve  325 , associated with the inlet port  120 - 1 , for holding the fluid entering the pump  105  through the inlet port  120 - 1 . 
       FIG. 5-7  illustrate the pump  105  in various positions, according to example implementations of the present subject matter. Although the operations of the pump  105  has been explained in considerable details with respect to a single inlet port and a single outlet port; it will be appreciated the principles recited herein extend to embodiments, where the pump  105  may include multiple inlet ports and multiple outlet ports. 
     Referring to  FIG. 5 , the pump  105  is illustrated in an idle state  500 , where the pump  105  is not operating. As mentioned earlier, the idle state  500  may refer to a state, when the fluid is not to be supplied to the fluid receiving unit  115 , and hence, the pump  105  may not be operated. Typically, in an idle state, to avoid accidental discharge of fluid, fluid ports, such as the fluid ports  120  may be separated by a shut off valve and an associated mechanism to control the opening and closing of the shut off valve with respect to the idle state or an active state of the pump  105 . According to an aspect of the present subject matter, the fluid ports  120  may be separated by the communication port  125 , which may control flow of fluid to the outlet port  120 - 2 . 
     In an example, in the idle state  500 , as the pump  105 , is not to be operated, no suction pressure may be applied to the vacuum port  335 . In this state, the biasing component  345  may push the diaphragm  130  (represented by broken lines) with a force acting upwards, i.e., towards the communication port  125 . As a result, the diaphragm  130  mates with the port plate  350  having the communication port  125 , thereby sealing the communication port  125 . The sealing of the communication port  125  may prevent flow of the fluid from the inlet port  120 - 1  to the outlet port  120 - 2 , thereby isolating the two fluid ports  120 . The isolation in turn prevents the pump  105  from leaking the fluid or pressure, thereby maintaining a requisite backpressure at the fluid receiving unit  115 . Thus, the diaphragm  130  and the communication port  130  may efficiently isolate the fluid ports  120  in the idle state  500  of the pump  105 . 
       FIG. 6  illustrates the pump  105  in an inlet active state  600 , according to example implementation of the present subject matter. The inlet active state  600  of the pump  105  may refer to a state of the pump  105 , where the pump  105  may be operated to open the inlet port  120 - 1  to allow the fluid to enter the pump  105 . In an example, to operate the pump  105 , a suction pressure in form of a vacuum pull (indicated by arrow  605 ) may be applied at the vacuum port  335 . For instance, the vacuum port  335  may be coupled to a vacuum source  610 , which may be operated to provide the suction pressure at the vacuum port  335 . Further, a vent valve  615  may be closed to maintain negative pressure in the pump  105 . The vent valve  615  may be provided in a pressure line  620  coupled to the vacuum port  335 . The vacuum source  610  and the vent valve  615  may be controlled by a control unit, such as, an electronic control unit of an apparatus, such as a printer system. 
     The suction pressure may pull the diaphragm  130  downwards, i.e., away from the communication port  125 , thereby causing the diaphragm to expand. As a result, the diaphragm may be displaced by a distance denoted by “Y” in  FIG. 6 . The displacement of the diaphragm  130  open the communication port  125  and creates a suction pressure (negative pressure) to open the inlet valve  325 - 1  corresponding to the inlet port  120 - 1 . In an example, the inlet valve  325 - 1  may be a one-way valve, such as an umbrella valve adapted to open when the negative pressure is created in the pump  105 . The umbrella valve may allow inflow of the fluid once the negative pressure is enough to lift the convex diaphragm from its seat to allow flow at a predetermined pressure in one way. The opening of the inlet port  120 - 1  and the inlet valve  325 - 1  allow the fluid to enter a fluid chamber  625 , which may now be created owing to displacement of the diaphragm  130 . 
     As the diaphragm  130  displaces, i.e., expands, the communication port  125  may open, and the inlet valve  325 - 1  together with the diaphragm  130  in the expanded form may form the fluid chamber  625 . The fluid from the inlet port  120 - 1  may be collected in the fluid chamber  625 . The inlet valve  325 - 1  and thus, the inlet port  120 - 1  may close again, once pressure applied at the vacuum port  335  is stopped, as illustrated in  FIG. 7 . 
       FIG. 7  illustrates the pump  105  in an outlet active state  700  of the pump  105 , according to example implementation of the present subject matter. The inlet active state  600  and the outlet active state  700  may be collectively referred to as an active state of the pump  105 . In the outlet active state  700 , pressure may no longer be applied to the vacuum port  335 , and vacuum creating the suction pressure is allowed to dissipate. For instance, in the outlet active state  700 , the pressure may be released through the vent valve  615 , which may open into the atmosphere. This allows the biasing component  345  to return to its original position as illustrated in  FIG. 5 , when the pump  105  is in the idle state  500 . Thus, the diaphragm  130  may be displaced by the distance “Y” in an upward direction, i.e., towards the communication port  125 . 
     The upward motion of the diaphragm  130  causes positive pressure to be developed, thereby opening the outlet valve  325 - 2  and the outlet port  120 - 2  to allow the fluid in the fluid chamber  625  to discharge through the outlet port  120 - 2 . Thus, the upward motion of the diaphragm  130  may cause the fluid to be discharged. 
     Repeated cycles of the inlet active state  600  as illustrated in  FIG. 5  and the outlet active state  700  as illustrated in  FIG. 7  to allow pumping of fluid at a given flow rate. Further, the frequency of cycles may also be adjusted to match the flow rate. This way a reciprocating motion of the diaphragm  130  may allow fluid to be pumped from the reservoir  110  to the fluid receiving unit  115 . 
     Further, the reciprocating motion of the diaphragm may not only control the fluid ports  120  but also the communication port  125 . As the communication port  125  is controlled by the diaphragm  130 , a separate mechanism for controlling the pump  105  and a separate mechanism for controlling the fluid ports  120  may not be required. Also, as described above, the communication port  125  along with the diaphragm  130  may efficiently isolate multiple fluid ports from each other to prevent accidental discharge of fluid or pressure. As a result, the pump  105  may be made compact and economical owing to lesser number of components and resources required to work the pump  105 . 
     In an example, upon discharging requisite amount of the fluid, the pump  105  may no longer be operated. Accordingly, the various components of the pump  105  may move to a position corresponding to the idle state  500  of the pump  105 , as illustrated in  FIG. 5 . For instance, the diaphragm  130  may be in a collapsed state sealing the communication port  125 , and the fluid port  120  may also be closed, thereby preventing inflow and outflow of the fluid. 
     In an example implementation of the present subject matter, the pump  105  may be implemented in a printer system, and operations of the pump  105  may be controlled by a control unit of the printer system. For instance, when ink (fluid) is to be supplied to a print head assembly, the control unit may provide a trigger to activate another pump to generate a vacuum pull at the vacuum port  335  to operate the pump  105 . As a result of vacuum pull being generated, the inlet port  120 - 1  may open to allow ingress of ink in a fluid chamber formed between the inlet valve  325 - 1  and the diaphragm  130 , which in an expanded state. The vacuum generation pump may be repeatedly operated to cause the diaphragm  130  to move in the pump  105 , thereby opening and closing the fluid ports  120  to transport the ink from an ink reservoir to the print head assembly, as described with reference to description of  FIG. 6  and  FIG. 7 . 
     Further, when no ink is to be supplied, the suction pressure may no longer be applied at the vacuum port  335 , and the pump  105  may move to its idle state, as depicted in  FIG. 5 . In the idle state, the fluid ports  120  may be suitably isolated by the diaphragm  130  and the communication port  125  to prevent discharge of ink to the print head assembly. This may also help in maintaining pressure at the print head assembly side. Owing to efficient isolation, wastage of ink may be prevented. Further, due to diaphragm  130  performing dual function of pumping the ink as well isolating the fluid ports, lesser number of components may now be involved, thus making the pump cost efficient and resource efficient. 
     Although examples for vacuum operated devices have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples for the vacuum operated pumps.