TW201434538A - Variable orifice outlet assembly - Google Patents

Abstract

A pumping system comprises a pump, first and second channels, a valve, and an actuator. The pump pumps fluid according to a pumping cycle. The first channel has a first fluid flow orifice with a first diameter, while the second channel has a second fluid flow orifice with a second diameter greater than the first diameter. The valve is configured to direct fluid from the pump to the first channel in a first state, and to the second channel in a second state. The actuator is configured to switch the valve into the first state during a high pressure period of the pumping cycle, and into the second state during a low pressure period of the pumping cycle.

Description

Variable orifice outlet assembly

The present invention generally relates to systems for dispensing hot melt adhesives. More specifically, the present invention relates to a pump outlet assembly for pressure control.

Hot melt dispensing systems are commonly used in the manufacture of assembly lines to automatically dispense one of the adhesives used in the construction of packaging materials such as boxes, cartons, and the like. The hot melt dispensing system generally includes a material tank, a heating element, a pump, and a dispenser. The solid polymer pellets are melted in the tank using a heating element prior to supplying the solid polymer pellets to the dispenser by a pump.

Adhesives are desirably applied at a substantially constant rate to provide a uniform layer of adhesive in many hot melt applications. Accordingly, conventional hot melt systems often use a heating supply system in which a pump and a dispenser are connected by a heated hose. A pump (typically a linear displacement piston pump having a single reciprocating piston) utilizes varying pressures within each pumping cycle to expel the molten adhesive from the tank. The hose carries the molten adhesive from the pump to the dispenser and acts as a first-rate volume accumulator or pressure damper to attenuate changes in pressure during the pump cycle of the pump.

In accordance with an embodiment of the present invention, a pumping system includes a pump, first and second passages, a valve, and an actuator. The pump pumps the fluid according to a pump cycle. The first passage includes a first fluid flow orifice having a first diameter and the second passage includes a second fluid flow orifice having a second diameter greater than one of the first diameters. The valve is configured to be in a first shape The fluid directs fluid from the pump to the first passage and directs the fluid to the second passage in a second state. The actuator is configured to switch the valve to the first state during one of the high pressure cycles of the pump cycle and to switch it to the second state during one of the low pressure cycles of the pump cycle.

In accordance with a second embodiment of the present invention, an adhesive system includes a melt system, a pump, a dispenser, and an outlet assembly. The melt system melts the adhesive and the pump pumps the adhesive from the melt system according to a pump cycle. The dispenser is configured to receive and dispense an adhesive from the pump. An outlet assembly is disposed between the pump and the dispenser to deliver the adhesive through a first diameter orifice during a first portion of the pumping cycle and to extend it during a second portion of the pumping cycle The molten adhesive pressure at the dispenser is smoothed through a second diameter orifice.

10‧‧‧System

12‧‧‧ Cold section

14‧‧‧hot section

16‧‧‧Air source

17‧‧‧Air control valve

18‧‧‧ Controller

20‧‧‧ container

22‧‧‧Feed assembly

24‧‧‧vacuum assembly

26‧‧‧feed hose

28‧‧‧Import

30‧‧‧Melt system

32‧‧‧ pump

34‧‧‧ dispenser

35A‧‧‧Air hose

35B‧‧ Air hose

35C‧‧‧Air hose

35D‧‧‧Air hose

36‧‧‧Motor

38‧‧‧Supply hose/feed supply hose

40‧‧‧Management

42‧‧‧Distribution module/module

44‧‧‧Export

100‧‧‧Export assembly

102‧‧‧Imported inflatable room

104‧‧‧First Path/Import First Path

106‧‧‧second pathway

108‧‧‧Export plenum

110‧‧‧ valve

112‧‧・ shuttle/sliding shuttle

114‧‧‧First opening

116‧‧‧second opening

118‧‧‧Actuator

120‧‧‧first orifice plug

122‧‧‧Second orifice plug

124‧‧‧First orifice/orifice

126‧‧‧Second orifice/orifice

PI‧‧‧import pressure/high inlet pressure/low inlet pressure

PO‧‧‧ export pressure

V1‧‧‧First valve status/valve status

V2‧‧‧Second valve status/valve status

△P ₁ ‧‧‧ permanent pressure drop / large pressure drop

△P ₂ ‧‧‧ permanent pressure drop / less pressure drop

Figure 1 is a schematic illustration of one of the systems for dispensing a hot melt adhesive.

Figure 2 is a simplified cross-sectional view of one of the outlet assemblies for the system of Figure 1.

Figure 3 is an exemplary graph of the inlet and outlet pressures in the outlet assembly of Figure 2 as a function of time.

1 is a schematic illustration of system 10, which is a system for dispensing a hot melt adhesive. System 10 includes a cold section 12, a hot section 14, an air source 16, an air control valve 17, and a controller 18. In the embodiment shown in FIG. 1, the cold section 12 includes a vessel 20 and a feed assembly 22 that includes a vacuum assembly 24, a feed hose 26, and an inlet 28. In the embodiment shown in FIG. 1, the hot section 14 includes a melting system 30, a pump 32, and a dispenser 34. The air source 16 is supplied to one of the components of the system 10 of the cold section 12 and the hot section 14 to compress the air source. The air control valve 17 is connected to the air source 16 via an air hose 35A and selectively controls the flow of air from the air source 16 through the air hose 35B to the vacuum assembly 24 and through the air hose 35C to the motor 36 of the pump 32. Air hose 35D connects air source 16 to dispenser 34 to bypass air control valve 17. Controller 18 and various components of system 10 For example, air control valve 17, melt system 30, pump 32, and/or dispenser 34) are connected for connection for operation of control system 10.

The components of the cold section 12 can be operated at room temperature without heating. The container 20 can be used to house one of the hoppers of solid adhesive pellets quantified by the system 10. Suitable adhesives can include, for example, a thermoplastic polymer glue such as ethylene vinyl acetate (EVA) or a metallocene. Feed assembly 22 connects vessel 20 to hot section 14 for transporting solid adhesive pellets from vessel 20 to hot section 14. Feed assembly 22 includes a vacuum assembly 24 and a feed hose 26. The vacuum assembly 24 is positioned in the container 20. Compressed air from air source 16 and air control valve 17 is delivered to vacuum assembly 24 to create a vacuum that causes solid adhesive pellets to flow into inlet 28 of vacuum assembly 24 and then through feed hose 26 Flow to the hot section 14. The feed hose 26 is sized using a diameter substantially larger than one of the diameters of the solid adhesive pellets to allow the solid adhesive pellets to flow freely through one of the tubes or other passages of the feed hose 26. Feed hose 26 connects vacuum assembly 24 to hot section 14.

The solid adhesive pellets are delivered from the feed hose 26 to the melting system 30. The melting system 30 can include a container (not shown) and a resistive heating element (not shown) for melting the solid adhesive pellets to form a hot melt adhesive in liquid form. Melting system 30 can be sized to have a relatively small adhesive volume (eg, about 0.5 liters) and configured to melt solid adhesive pellets in a relatively short period of time. Pump 32 is driven by motor 36 to pump hot melt adhesive from melt system 30 to dispenser 34 via supply hose 38. Motor 36 can be driven by a pulse of compressed air from air source 16 and air control valve 17 to drive one of the air motors. Pump 32 may, for example, be driven by motor 36 as a linear displacement pump (such as a dual action piston pump). In the illustrated embodiment, the dispenser 34 includes a manifold 40 and a dispensing module 42. The hot melt adhesive from pump 32 is received in manifold 40 and dispensed via module 42. The dispenser 34 selectively discharges the hot melt adhesive thereby allowing the hot melt adhesive to be sprayed out of the outlet 44 of the module 42 onto an article, such as a package, a box, or benefiting from the system 10 Another item of heat-melting adhesive. Module 42 can be applied One of a plurality of modules of a portion of the adapter 34. In an alternate embodiment, the dispenser 34 can have a different configuration, such as a hand gun type dispenser. Some or all of the components of the hot section 14 (including the melt system 30, the pump 32, the supply hose 38, and the dispenser 34) may be heated to maintain the hot melt adhesive in a liquid throughout the thermal section 14 during the dispensing process. status.

System 10 can be, for example, part of an industrial process for packaging and sealing a package of cardboard packages and/or packages. In an alternative embodiment, system 10 may be modified as necessary for a particular industrial program application. For example, in an embodiment (not shown), pump 32 can be separated from melt system 30 and instead attached to dispenser 34. The hose system 38 is thus supplied to connect the melt system 30 to the pump 32.

The outlet assembly 100 connects the pump 32 to the supply hose 38. The outlet assembly 100 is a variable orifice outlet assembly that is configured to reduce variations in fluid pressure at the supply hose 38 and manifold 40 during pumping cycles across the pump 32. The outlet assembly 100 is described in detail below with respect to Figures 2 and 3.

FIG. 2 illustrates an outlet assembly 100 disposed between the pump 32 and the supply hose 38. In the depicted embodiment, the outlet assembly 100 includes an inlet plenum 102, a first passage 104, a second passage 106, an outlet plenum 108, and a valve 110 (having a shuttle 112 and a first opening 114 and a second opening 116, respectively) The actuator 118, the first orifice plug 120 (having a first orifice 124) and the second orifice plug 122 (having a second orifice 126). The outlet assembly 100 is a variable orifice outlet assembly that is configured to select between two (or (in alternative embodiments)) fluid paths from the pump 32 to the supply hose 38. Sexual switching.

The pump 32 pumps the hot melt adhesive from the melting system 30 to the inlet plenum 102 of the outlet assembly 100 at an inlet pressure P _I . The inlet plenum 102 and the outlet plenum 108 are chambers, passages or sump for accumulating liquid adhesive. Entering the inlet plenum P ₁ changes the liquid inlet 102 of the adhesive of the pressure pump 32 of the pumping function of one cycle (see discussion of Figure 3 below). In an exemplary embodiment, pump 32 is a linear displacement dual action piston pump. When the pump 32 reciprocates between the upstroke and the downstroke, the liquid is forced into the inlet plenum 102. During the transition between the strokes of the pump 32, the inlet pressure P _I temporarily decreases. The relative stroke of pump 32 may also vary slightly in pump pressure.

The valve 110 is provided by one of the switching valves from the inlet plenum 102 to one of the first passage 104 or the second passage 106. In the depicted embodiment, valve 110 is a shuttle valve that includes a sliding shuttle 112 having a first opening 114 and a second opening 116. The inlet and outlet plenums 102 and 108 are depicted as having bifurcated passages that communicate with the inlet first passage 104 and the second passage 106, respectively, and the individual branches that communicate from the inlet first passage 104 and the second passage 106. The first passage 104 includes a first orifice 124 and the second passage 106 includes a second orifice 126. The first aperture 124 and the second aperture 126 are narrower than the apertures of the first opening 114 and the second opening 116 and the first via 104 and the second via 106. As described in further detail below, first aperture 124 and second aperture 126 have diameters selected to produce a desired permanent pressure drop ΔP ₁ and ΔP ₂ between inlet plenum 102 and outlet plenum 108, respectively. The first passage 104 and the second passage 106 have the same diameter as the first opening 114 and the second opening 116, such that the diameters of the first aperture 124 and the second aperture 126 determine the difference between ΔP ₁ and ΔP ₂ . .

In the depicted embodiment, the valve 110 has a first valve state V1 and a second valve state V2 that correspond to the position of the shuttle shuttle 112. The valve 110 is shown in a first valve state V1, wherein the sliding shuttle 112 aligns the first opening 114 with the first passage 104 and seals the second passage 106, thereby passing from the inlet plenum 102 to the outlet plenum 108 via the first The passage 104 and the first orifice 124 provide a fluid path. In the second valve state V2 (not shown), the shuttle 112 aligns the second opening 116 with the second passage 106 and seals the first passage 104, whereby the second passage 106 is passed from the inlet plenum 102 to the outlet plenum 108 via the second passage 106 And the second orifice 126 provides a fluid path. In an alternate embodiment, valve 110 can be, for example, a ball valve or a similar valve type having a single configurable or re-steerable opening rather than individual first opening 114 and second opening 116. As described above, when the valve 110 is in the first valve state V1, the permanent pressure drop between the inlet plenum 102 and the outlet plenum 108 is ΔP ₁ . When the valve 110 is in the second valve state V2, the permanent pressure drop between the inlet plenum 102 and the outlet plenum 108 is ΔP ₂ . Actuator 118 switches valve 110 between first valve state V1 and second valve state V2 during the pumping cycle of pump 32. As described in further detail below, valve state V1 is used during the continuous stroke of pump 32, while valve state V2 is used during pump switching.

Actuator 118 is coupled to a valve actuator such as a motor or hydraulic actuator of valve 110. The actuator 118 drives the valve 110 in accordance with a control line cl (a mechanical or electrical control line that matches the state of the valve 110 to one of the cycles of the pump 32 as described in further detail below with respect to FIG. 3). The control line cl can, for example, be driven by a hydraulic pilot line by a change in pump pressure within the pump 32, and the actuator 118 can be a hydraulic switch. Alternatively, the actuator 118 can be an electrical switch and the control line cl can carry an electrical signal to one of the wires of the actuator 118. Such electrical signals may be provided by controller 18 to synchronize actuator 118 with a pump cycle (discussed above with respect to FIG. 1), or may be reactive from one of pump 32 or adjacent pump 32. Pressure reading of the device. By switching valve 110 between valve states V1 and V2, actuator 118 controls whether fluid flowing through outlet assembly 100 travels through first orifice 124 or second orifice 126. In this manner, the actuator 118 controls whether the pressure drop between the inlet plenum 102 and the outlet plenum 108 is ΔP ₁ (corresponding to valve state V1) or ΔP ₂ (corresponding to valve state V2).

In the depicted embodiment, the first aperture 124 has a diameter that is narrower than one of the second apertures 126. As is well known in the art, a narrower aperture produces a greater permanent pressure drop. Accordingly, ΔP ₁ across the first aperture 124 is greater than the permanent pressure drop ΔP ₂ across the second aperture 126. By using a period of high inlet pressure P _{I to} match a larger pressure drop ΔP ₁ and a period of low inlet pressure P _I matching a smaller pressure drop ΔP ₂ , the outlet assembly 100 reduces fluctuations in the outlet pressure P _O . To this end, the actuator 118 switches the valve 110 to the valve state V1 during the relatively high pressure continuous stroke of the pump 32 and switches it to the valve state V2 during the relatively low pressure transition of the pump 32. In this manner, the outlet assembly 100 produces a substantially less uniform outlet pressure P _O that is substantially less varied during each pumping cycle of the pump 32 than the inlet pressure P _I .

In the depicted embodiment, the first aperture 124 and the second aperture 126 travel through the first aperture plug 120 and the second aperture plug 122, respectively. First aperture plug 120 and second aperture plug 122 are removable inserts that can be fitted into outlet assembly 100 to provide an aperture of a desired diameter. The first aperture plug 120 and the second aperture plug 122 can, for example, be screwed into the outlet assembly 100 to provide the apertures 124 and 126 in the sealed threaded cylinders in the first passage 104 and the second passage 106, respectively. Shaped component. The first orifice plug 120 and/or the second orifice plug 122 may be replaced for similar plugs having orifices of different diameters to adjust the permanent pressure drop ΔP ₁ and ΔP ₂ to achieve an outlet pressure P _O across the pump 32 The pump cycle is reduced by a change. In an alternate embodiment, the first aperture 124 and the second aperture 126 can be formed in a permanent structure within the outlet assembly 100.

Although the outlet assembly 100 has been described above as including one variable outlet assembly having two individual orifices 124 and 126 having different diameters, alternative embodiments may include more or fewer orifices. Some alternative embodiments may, for example, dispense with valve 110 and replace orifices 124 and 126 with a single aperture having a continuously variable diameter that is controllable to compensate for fluctuations in inlet pressure P _I from pump 32. In other embodiments, valve 110 can be switched between three or more orifice passages for greater granularity of pressure control than the two orifice embodiments described above.

3 is a graph of one of the inlet pressure P _I and the outlet pressure P _O of the outlet assembly 100 as a function of time, illustrating the switching of the valve 110 from valve state V1 to valve state V2 during pump switching. FIG. 3 is intended only to be illustrative of one of the fluid pressures in the outlet assembly 100 and is not drawn to scale. As described above with respect to FIG. 2, the actuator 118 switches the valve 110 of the outlet assembly 100 between valve states V1 and V2. Valve state V1 delivers fluid through first orifice 124, while valve state V2 delivers fluid through second orifice 126. Because the first orifice 124 is narrower than the second orifice 126, the permanent pressure drop ΔP ₁ in the valve state V1 is greater than the permanent pressure drop ΔP ₂ in the valve state V2. The outlet assembly reduces fluctuations in the outlet pressure P _O (as shown) by switching from valve state V1 to valve state V2 during a relatively low pressure pump shift cycle. As illustrated in Figure 3, P _I in the pump top and bottom of the converter 32 may be subjected to different pressure drops. Inlet and outlet plenum 102 and 108 may be (in some embodiments) acts as a fluid accumulator, thereby further smoothing the outlet pressure P _O into one of a function of time. Cartridge outlet 100 thus increasing the uniformity of the outlet pressure P _O, the dispenser 34 so as to allow to uniformly apply hot melt adhesive coating. Although the outlet assembly 100 has been described as the feed supply hose 38, the alternate embodiment may dispense with the supply hose 38 and pump the adhesive directly into the dispenser 34 because the outlet assembly 100 is substantially dispensed with The need to supply the accumulator function of the hose 38. The outlet assembly 100 thus enables smoothing of the adhesive in a more compact system.

While the invention has been described with respect to the preferred embodiments, the embodiments of the present invention may be modified in the form and details without departing from the spirit and scope of the invention.

30‧‧‧Melt system

32‧‧‧ pump

38‧‧‧Supply hose/feed supply hose

40‧‧‧Management

100‧‧‧Export assembly

102‧‧‧Imported inflatable room

104‧‧‧First Path/Import First Path

106‧‧‧second pathway

108‧‧‧Export plenum

110‧‧‧ valve

112‧‧・ shuttle/sliding shuttle

114‧‧‧First opening

116‧‧‧second opening

118‧‧‧Actuator

120‧‧‧first orifice plug

122‧‧‧Second orifice plug

124‧‧‧First orifice/orifice

126‧‧‧Second orifice/orifice

PI‧‧‧import pressure/high inlet pressure/low inlet pressure

PO‧‧‧ export pressure

V1‧‧‧First valve status/valve status

V2‧‧‧Second valve status/valve status

△P ₁ ‧‧‧ permanent pressure drop / large pressure drop

△P ₂ ‧‧‧ permanent pressure drop / less pressure drop

Claims (21)

A pumping system comprising: a pump that pumps a fluid according to a pump cycle; a first passage that includes a first orifice having a first diameter; and a second passage that includes greater than a second orifice of one of the first diameters; a valve configured to direct the fluid from the pump to the first passage in a first state and in a second state Fluid is directed to the second passage; and an actuator configured to switch the valve to the first state during one of the pump cycle high pressure cycles and during a low pressure cycle of the pump cycle It switches to the second state. The pumping system of claim 1, wherein the first orifice is disposed through one of the first passages of the first passage and the second orifice is disposed through one of the second passages The plug can be removed. A pumping system according to claim 1, wherein the actuator comprises an electronic switch. The pumping system of claim 3, wherein the electronic switch actuates the valve in response to a sensed pressure reading from the pump. The pumping system of claim 3, further comprising: a pump motor configured to drive the pump; and a controller configured to control the pump motor and the electronic switch in accordance with the pump cycle . A pumping system according to claim 1, wherein the actuator comprises a hydraulic switch. The pumping system of claim 6, wherein the hydraulic opening relationship is controlled by a hydraulic control line driven by a change in pressure in the pump. The pumping system of claim 1, wherein the pump is a double acting piston pump. An adhesive system comprising: a melting system for melting an adhesive; a pump arranged to pump the adhesive from the melting system according to a pump cycle; a dispenser configured to Receiving and dispensing the adhesive from the pump; and an outlet assembly disposed between the pump and the dispenser to deliver the adhesive through a first portion of the pumping cycle A diameter orifice and it is delivered through a second diameter orifice during a second portion of the pumping cycle to smooth the melt adhesive pressure at the dispenser. The adhesive system of claim 9, wherein the first diameter orifice has a diameter that is narrower than one of the second diameter orifices, and wherein the outlet assembly further comprises a valve that is arranged to convert at the pump The adhesive is delivered through the second diameter aperture and otherwise passes through the first diameter aperture. The adhesive system of claim 10, wherein the valve is a shuttle valve. The adhesive system of claim 10, wherein at least one of the first diameter aperture and the second diameter aperture is located in a removable plug. The adhesive system of claim 9, further comprising a supply hose configured to carry the adhesive from the outlet assembly to the dispenser. An outlet assembly for a pump, the outlet assembly comprising: an inlet plenum arranged to receive fluid from the pump; an outlet plenum arranged to supply fluid to a downstream component; An orifice disposed fluidly between the inlet plenum and the outlet plenum and having a first orifice diameter; a second orifice fluidly disposed in the inlet plenum and the outlet plenum Between and having a second orifice diameter greater than one of the first orifice diameters; a valve having two valve states: a first valve state, wherein the fluid is delivered from the inlet plenum to the outlet plenum via the first orifice; and a second valve state via which the fluid is injected from the inlet plenum Served to the outlet plenum; and an actuator configured to switch the valve from the first valve state to the second valve state during transition of the pump. The outlet assembly of claim 14, wherein the first orifice is located in a first passage connecting one of the inlet and outlet plenums, and the second orifice is located in one of the inlet and outlet plenums connected to the second In the path. The outlet assembly of claim 15, wherein the valve is a shuttle valve, the shuttle valve being arranged to open the inlet plenum for the first passage or the second passage. The outlet assembly of claim 14, wherein the downstream component is a fluid dispenser. The outlet assembly of claim 14, wherein the flow system thermally melts the adhesive. A method for controlling an outlet pressure of a pump having a pumping cycle, the method comprising: directing fluid through a first orifice during a high pressure period of the pumping cycle corresponding to a continuous pump stroke; The fluid is directed through a second orifice that is wider than one of the first orifices during a low pressure cycle corresponding to one of the pump cycles of pump switching. The method of claim 19, wherein: directing fluid through the first orifice comprises switching a valve to fluidly connect the pump to one of the first orifice states; and directing fluid through the second orifice The port includes switching the valve to a second valve state in which the pump is fluidly coupled to the second orifice. The method of claim 20, further comprising actuating the valve based on a pressure in the pump.