Trigger pump dispenser

Abstract

The trigger pump dispenser (10) comprises a body (20), an outlet nozzle (35), a pump chamber (190), a piston (25) for defining a variable volume within the pump chamber (190), the piston (25) being movable between a retracted position that increases the chamber volume and an inserted position that decreases the chamber volume, a trigger (60) connected to the piston (25) and movable between a start position in which the piston (25) is in the retracted position and a depressed position in which the piston (25) is in the inserted position, and biasing means (65a, 65b) provided for biasing the trigger (60) toward its retracted position.

Description

Technical Field

[0001] The present invention generally relates to dispensers for liquid products, and more particularly to so-called "trigger pumps" having a trigger operable to drive a piston along a pump chamber against the action of a spring and place a liquid product under pressure from the pump chamber through a discharge orifice in a nozzle.

[0002] Some aspects and embodiments of the present invention generally relate to valves, and more particularly, but not exclusively, to valves for pumps such as valves for trigger pumps.

Summary of the Invention

Means for Solving the Problems

[0003] One aspect of the present invention provides a trigger pump dispenser comprising a body, an outlet nozzle, a pump chamber, a piston for defining a variable volume within the pump chamber, the piston being movable between a retracted position that increases the chamber volume and an inserted position that decreases the chamber volume, a trigger connected to the piston and movable between a starting position where the piston is in the retracted position and a pushed-down position where the piston is in the inserted position, and a biasing means for biasing the trigger toward its retracted position, wherein the pump includes an inlet port and an outlet port defined by the body and adapted to communicate with the pump chamber, and the pump is configured such that the liquid to be discharged is in the pump chamber and the volume of the pump chamber is reduced The pump chamber includes an inlet valve adapted to close the inlet port as the piston moves from the retracted position to the inserted position, the inlet valve adapted to open the inlet port as the pump chamber volume increases as the piston moves from the inserted position to the retracted position and the liquid to be discharged is drawn into the pump chamber through the inlet port, the outlet valve adapted to open the outlet port as the volume of the pump chamber decreases as the liquid in it is discharged through the outlet port and adapted to close as the volume of the pump chamber increases, and the outlet valve includes a pre-compression valve that can be operated to allow the liquid to pass through the outlet only after a predetermined high pressure has been established in the pump chamber.

[0004] One aspect of the present invention provides a trigger pump dispenser comprising a body, an outlet nozzle, a pump chamber, a piston for defining a variable volume within the pump chamber, the piston being movable between a retracted position for increasing the chamber volume and an inserted position for decreasing the chamber volume, a trigger connected to the piston and movable between a starting position where the piston is in the retracted position and a pushed-down position where the piston is in the inserted position, and a biasing means for biasing the trigger toward its retracted position, wherein the pump includes an inlet port and an outlet port defined by the body and adapted to communicate with the pump chamber, and the pump is discharged A liquid is present in the pump chamber, and the pump chamber is equipped with an inlet valve adapted to close the inlet port as the piston moves from the retracted position to the inserted position as the volume of the pump chamber decreases, the inlet valve adapted to open the inlet port as the pump chamber volume increases as the piston moves from the inserted position to the retracted position as the discharged liquid is drawn into the pump chamber through the inlet port, and the outlet valve adapted to open the outlet port as the volume of the pump chamber decreases as the liquid within it is discharged through the outlet port, and to close as the volume of the pump chamber increases.

[0005] In some embodiments, during the suction process, the piston moves away from the valve, so that a vacuum is formed in the cylinder chamber, and the negative pressure causes the lip of the inlet valve to collapse, opening the inlet opening, at which point the liquid can enter the cylinder chamber through the inlet path. During the pressurizing process, the piston moves toward the valve, so that excess pressure is accumulated in the system, and the sealing lip of the inlet valve is pressed against the outer wall of the cylinder, sealing the inlet opening. Once a certain pressure level is exceeded, the outlet valve closes backward, thereby creating a free passage between the outer valve member and the inner valve member.

[0006] The predetermined high pressure can be defined, for example, by the material of the inner member of the valve. Alternatively, or in addition to that, the predetermined high pressure can be defined, for example, by the design of the conical connection between the outer jacket and the inner sealing element.

[0007] The dispenser may include a valve member, which includes a first member and a second member, which are formed separately and connectable to each other, with one of these members providing an inlet valve function and the other providing an outlet function.

[0008] A gap can be created by the movement of a valve, which allows the liquid to flow from the cylinder space into the outlet channel.

[0009] The valve opening distance can be determined by the length of the central stop section.

[0010] In some embodiments, when the system pressure falls below a certain level, the outlet valve returns to its original position and closes, sealing the outer portion of the valve and allowing the connection from the cylinder chamber to the outlet side to be closed again.

[0011] The trigger and the biasing mechanism can be formed from the same components.

[0012] The biasing mechanism may include a pair of curved spring arms spaced apart from each other. These arms may be unconnected (except via a trigger).

[0013] The arm can be joined to the trigger at a hinge point, allowing the arm to move hinged relative to the trigger when in use. This can be used, for example, to provide a stronger spring action.

[0014] The trigger and spring arm can be formed as a single unit.

[0015] Dispenser components, such as actuators, can be formed from, for example, post-consumer recycled (PCR) plastics. For instance, actuators can be formed from 20-80% PCR-containing material.

[0016] A further embodiment provides a valve element for providing a pre-compression function to the pumping cylinder of a trigger sprayer, which enables the discharge of pressurized liquid only when the pressure of the liquid in the cylinder exceeds a certain predetermined level.

[0017] A further embodiment provides a conversion valve for converting a non-pre-compression pump to pre-compression.

[0018] A further embodiment provides a trigger pump dispenser comprising a body, an outlet nozzle, a pump chamber, a piston for defining a variable volume within the pump chamber, the piston being movable between a retracted position that increases the chamber volume and an inserted position that decreases the chamber volume, a trigger connected to the piston and movable between a starting position where the piston is in the retracted position and a pushed-down position where the piston is in the inserted position, and a biasing means for biasing the trigger toward its retracted position, wherein the pump comprises an inlet port and an outlet port defined by the body and adapted to communicate with the pump chamber, and the pump is such that as the liquid to be discharged is in the pump chamber and the volume of the pump chamber decreases, the piston is inserted from the retracted position The pump has an inlet valve adapted to close the inlet port when it moves to a position, the inlet valve adapted to open the inlet port when the discharged liquid is drawn into the pump chamber through the inlet port as the pump chamber volume increases as the piston moves from the insertion position to the retraction position, the outlet valve adapted to open the outlet port when the volume of the pump chamber decreases as the liquid in it is discharged through the outlet port, and adapted to close when the volume of the pump chamber increases, the outlet valve has a pre-compression valve that can be operated to allow the liquid to pass through the outlet only after a predetermined high pressure has been established in the pump chamber, the trigger and biasing means are formed in the same component, the biasing means comprises a pair of spaced-apart curved spring arms.

[0019] A further embodiment provides a trigger pump dispenser comprising a body, an outlet, a pump chamber, a piston for defining a variable volume within the pump chamber, the piston being movable between a retraction position where the chamber volume is large and an insertion position where the chamber volume is small, a trigger connected to the piston and movable between a starting position where the piston is in the retraction position and a pushed-down position where the piston is in the insertion position, and a biasing means for biasing the trigger toward its retraction position, wherein the trigger and the biasing means are formed from the same component, and the biasing means comprises a pair of spaced-apart curved spring arms.

[0020] A further embodiment provides an actuator for a trigger pump dispenser comprising a trigger movable between a retracted position and a depressed position when in use, and a spring for biasing the trigger toward the retracted position, wherein the trigger and the biasing means are formed of the same component, and the spring comprises a pair of spaced-apart curved arms.

[0021] These arms can be considered virtually identical.

[0022] The arm can be roughly J-shaped or roughly U-shaped.

[0023] The arms can extend approximately parallel to each other.

[0024] The spring arm can be made almost straight along the vertical plane.

[0025] The spring arm can be bent in a horizontal plane.

[0026] The end of the arm opposite the trigger may include a plane. The arm can be a simple continuous curve (other than a plane).

[0027] The end of the arm opposite the trigger may include a hook or wedge.

[0028] The arm can extend from the trigger at one end and is free at the other end, i.e., it can be supported / connected only at one end.

[0029] Each arm can be joined to the trigger at a hinge point, whereby the arm can move in a hinged manner relative to the trigger during use.

[0030] The actuator can be integrally formed (e.g., molded) from, for example, a plastic material.

[0031] The actuator can be formed from post-consumer recycled (PCR) plastic.

[0032] The actuator can be formed from PCR content in the range of 20% - 80%.

[0033] The present invention also provides an actuator as described herein in combination with a trigger pump dispenser as described or defined herein.

[0034] The present invention also provides a trigger pump dispenser having an actuator as described or defined herein.

[0035] Some aspects and embodiments provide or relate to a pre-compression valve operable to allow liquid to pass through an outlet only after a predetermined high pressure has been established.

[0036] The pump outlet valve can be or can include a pre-compression valve operable to allow liquid to pass through an outlet only after a predetermined high pressure has been established within the pump chamber.

[0037] Some embodiments provide a pre-compression valve that reduces the amount of the body portion by a compact design. Thereby, this valve can facilitate a lightweight trigger pump.

[0038] Some embodiments include an outer valve member and an inner valve member.

[0039] In some embodiments, during the suction process, the piston can be moved away from the valve, thereby creating a vacuum in the cylinder chamber. The negative pressure causes the lip of the inlet valve to collapse, opening the inlet opening. The liquid can then enter the cylinder chamber through the inlet path.

[0040] During the pressurization process, the piston can move toward the valve, thus accumulating excess pressure in the system. The sealing lip of the inlet valve can be pressed against the outer wall of the cylinder, sealing the inlet opening.

[0041] When a certain pressure level is exceeded, the outlet valve can be closed backward, thereby creating a free passage between the outer valve member and the inner valve member. The pressure level for switching can be defined by the material of the inner member of the valve and the design of the conical connection between the outer jacket and the inner sealing element. The opening distance can be determined by the length of the central stop bar.

[0042] The gap created by the movement of the valve may allow the liquid to flow from the cylinder space into the outlet channel.

[0043] If the system pressure falls below a certain level, the outlet valve returns to its original position and closes, sealing the outer portion of the valve and allowing the connection from the cylinder chamber to the outlet side to be closed again.

[0044] A trigger pump dispenser may include a main body, an outlet nozzle, a pump chamber, a piston for defining a variable volume within the pump chamber, the piston being movable between a retraction position that increases the chamber volume and an insertion position that increases the chamber volume, a trigger connected to the piston and movable between a starting position where the piston is in the retraction position and a pushed-down position where the piston is in the insertion position, and a biasing means for biasing the trigger toward its retraction position.

[0045] The pump may have inlet and outlet ports defined by the main body and adapted to communicate with the pump chamber.

[0046] The pump may be equipped with an inlet valve adapted to close the inlet port when the liquid to be discharged is in the pump chamber and the piston moves from the retracted position to the inserted position as the volume of the pump chamber decreases.

[0047] The inlet valve can be adapted to open the inlet port when the liquid to be discharged is drawn into the pump chamber through the inlet port as the pump chamber volume increases as the piston moves from the insertion position to the retraction position.

[0048] The outlet valve can be adapted to open the outlet port when the volume of the pump chamber decreases as the liquid inside is discharged through the outlet port, and to close it when the volume of the pump chamber increases.

[0049] The outlet valve may include a pre-compression valve that can be operated to allow the liquid to pass through the outlet only after a predetermined high pressure has been established within the pump chamber.

[0050] This aspect of the present invention therefore provides a pre-compression function to the pumping cylinder of a trigger sprayer, which enables the discharge of pressurized liquid only when the pressure of the liquid in the cylinder exceeds a certain predetermined level.

[0051] A pre-compression system can be used to prevent the fluid from being released at too low a pressure, and can improve the spray pattern by pushing the liquid out of the outlet nozzle at a predetermined relatively high pressure.

[0052] Functional description: A spare compression valve, as shown in the example. During the suction stroke, the piston (not shown here) moves away from the valve, causing a vacuum to build up in the cylinder chamber. The negative pressure causes the lip of the inlet valve to collapse, opening the inlet opening.

[0053] The liquid can enter the cylinder chamber here via the inlet passage.

[0054] During the pressurization process, the piston moves toward the valve, and therefore excess pressure accumulates in the system. The sealing lip of the inlet valve is pressed against the outer wall of the cylinder to seal the inlet opening.

[0055] When a certain pressure level is exceeded, the outlet valve closes backward, thereby creating a free passage between the outer and inner valve sections. The pressure level for switching is defined by the material of the inner valve section and the design of the conical connection between the outer jacket and the inner sealing element. The opening distance is determined by the length of the central stop bar.

[0056] The gap created by the movement of the valve allows the liquid to flow from the cylinder space into the outlet channel.

[0057] If the system pressure falls below a certain level, the outlet valve returns to its original position and closes, sealing the outer portion of the valve and allowing the connection from the cylinder chamber to the outlet side to be closed again.

[0058] One advantage of this valve concept is that, for example, it is an independent pre-compression valve element that can be used to constructively convert an existing non-pre-compression pump to pre-compression.

[0059] The present invention also provides a trigger pump including a valve as described herein.

[0060] Different aspects and embodiments of the present invention can be used separately or in combination.

[0061] Examples of the present invention are shown in the accompanying drawings. [Brief explanation of the drawing]

[0062] [Figure 1] This is a diagram of a trigger pump dispenser. [Figure 2] This is a diagram of a trigger pump dispenser. [Figure 3] This is a diagram of a trigger pump dispenser. [Figure 4] This is an exploded view showing the components of a dispenser. [Figure 5] This diagram shows these components in more detail. [Figure 6] This diagram shows these components in more detail. [Figure 7] This diagram shows these components in more detail. [Figure 8] This diagram shows these components in more detail. [Figure 9] This diagram shows these components in more detail. [Figure 10] This diagram shows these components in more detail. [Figure 11] This diagram shows these components in more detail. [Figure 12] This diagram shows these components in more detail. [Figure 13] This diagram shows these components in more detail. [Figure 14] This is a diagram showing an actuator. [Figures 15a-15c] This is a diagram showing the operation of the actuator. [Figure 16] This figure shows examples of different versions of a spring arm. [Figure 17] This diagram shows the valve engaged with the pump chamber of the dispenser body. [Figures 18a-18b] This diagram shows the two separated parts of the valve. [Figures 19a-19c] This diagram shows the valve parts snapped together. [Figure 20] This is a diagram showing the inlet / outlet valves. [Figure 21] This figure shows a bayonet-mounted version of a trigger pump dispenser formed according to the present invention. [Figure 22] This figure shows dispensers with different external designs formed according to the present invention. [Figure 23] This figure shows dispensers with different external designs formed according to the present invention. [Figure 24] This figure shows dispensers with different external designs formed according to the present invention. [Modes for carrying out the invention]

[0063] First, referring to Figures 1-4, the trigger pump dispenser 10 is shown. Figure 4 is an exploded view showing the components of the dispenser, namely the shroud 15, body 20, piston 25, actuator 30, nozzle 35, visor 40, valve 42 including valve (upper) 45 and valve (lower) 50, and screw-in closure 55.

[0064] Figures 5-14 show these components in more detail.

[0065] The actuator 30 is shown in Figure 14. The actuator 30 includes a trigger 60, with two spaced-apart spring arms 65a and 65b extending rearward from one end of the trigger. Each spring arm 65a and 65b is substantially J-shaped and connected at one end via a hinge point 70. At the other end of each arm, they include a plane 75 and a terminal hook / wedge 80. The top of the trigger is provided with a pair of lugs 85, each having a hole 86 for engaging a corresponding pin 21 on the body 20. The trigger can rotate relative to the body.

[0066] Figures 15a to 15c show the operation of the actuator 30.

[0067] Figure 15a shows the actuator 30 in a relaxed, retracted position, attached to the main body (via lugs 85 and pins 21). The spring arm plane 75 rests on a horizontal flange 22 formed on the main body, and the spring hook 80 engages behind the vertical flange 23, which restrains the spring arm.

[0068] During use, the trigger 60 is pulled against a bias provided by the spring arm. As the trigger moves progressively, the arms 65a and 65b bend or deform and also move hingely relative to the trigger (downward as shown in the drawing). This arrangement has been found to generate more force.

[0069] Figure 16 shows examples of different versions of the spring arm.

[0070] Figures 17-20 show the inlet / outlet valve 142 and provide a functional explanation of the functionality of the pre-compression valve.

[0071] Figure 17 shows the valve 142 engaged with the pump chamber 190 of the dispenser body.

[0072] The chamber 190 includes an inlet opening 191 that provides an inlet route and an outlet opening 192 that provides an outlet route.

[0073] Valve 142 includes an upper part 145 and a lower part 150. Figures 18a and 18b show the two separated parts, and Figures 19a-c show the parts snap-fitted together.

[0074] The upper part 145 includes an annular sealing lip 146, and within the radial direction of the lip is a frustoconical member 147 containing a central flow hole 148. Below the member 147, arc-shaped clip portions 149a, with holes 149b formed between them, are spaced apart from each other.

[0075] The lower part 150 includes a frustoconical central seal 151 supported on an inclined ring 152. The ring 152 is connected to a peripheral mounting ring 153, to which an upper clip portion 149a connects, securing the upper and lower parts together. A frustoconical stop portion 154 hangs down from the underside of the seal 151.

[0076] During the suction process, the piston (not shown here) moves away from the valve 142, thereby creating a vacuum in the cylindrical pump chamber 190. The negative pressure causes the lip 146 of the inlet valve to tilt (indicated by the dotted line), opening the inlet opening 191.

[0077] The liquid can enter the cylinder chamber 190 here via the inlet path.

[0078] During the pressurization process, the piston moves toward the valve 142, and thus excess pressure accumulates in the system. The sealing lip 146 of the inlet valve is pressed against the outer wall of the cylinder to seal the inlet opening 191.

[0079] When a certain pressure level is exceeded, the outlet valve seal 151 closes to the rear (shown by a dotted line in Figure 20), thereby creating a free passage between the outer valve member and the inner valve member. This provides pre-compression functionality. The pressure level for switching is defined by the material of the inner member of the valve and the design of the conical connection between the outer jacket and the inner sealing element. The opening distance is determined by the length of the stop portion 154 when it abuts against the rear wall 193 of the chamber 190.

[0080] The gap created by the movement of the valve allows the liquid to flow from the cylinder space into the outlet channel.

[0081] When the system pressure falls below a certain level, the outlet valve seal returns to its original position and closes, sealing the outer portion of the valve and allowing the connection from the cylinder chamber to the outlet to close again.

[0082] One advantage of this valve concept is that, for example, it is an independent pre-compression valve element that can be used to constructively convert an existing non-pre-compression pump to pre-compression.

[0083] Figure 21 shows a bayonet-mounted version of the trigger pump dispenser 210 formed according to the present invention. This dispenser is similar to the dispensers in Figures 1-15, except that it is provided with a bayonet-style mounting means instead of a threaded collar for securing the dispenser to the container.

[0084] Figures 22-24 show dispensers 310, 410, and 510 with three different external designs formed according to the present invention.

[0085] There is no intention to limit the disclosure to any specific form.

[0086] While exemplary embodiments of the present invention have been disclosed in detail herein, it will be understood that the present invention is not limited to the exact embodiments shown, and that various changes and modifications can be made therein without departing from the scope of the invention by those skilled in the art.

Claims

1. A trigger pump dispenser (10) comprising a main body (20), an outlet nozzle (35), a pump chamber (190) having a rear wall (193) and an outer wall, a piston (25) for defining a variable volume in the pump chamber, the piston being movable between a retraction position that increases the chamber volume and an insertion position that decreases the chamber volume, a trigger (60) connected to the piston and movable between a starting position where the piston is in the retraction position and a pushed-down position where the piston is in the insertion position, and biasing means (65a, 65b) for biasing the trigger toward its starting position, The pump chamber (190) comprises an inlet port (191) and an outlet port (192), and the trigger pump dispenser comprises a valve (142) adapted to close the inlet port when the piston moves from the retracted position to the insertion position as the volume of the pump chamber decreases, and the valve adapted to open the inlet port when the volume of the pump chamber increases as the piston moves from the insertion position to the retracted position and the volume of the pump chamber increases, and the valve The trigger pump dispenser, wherein the valve is configured to open the outlet port when the volume of the pump chamber decreases as the liquid inside is discharged through the outlet port, and to close the outlet port when the volume of the pump chamber increases, and the valve is configured to operate to allow the liquid to pass through the outlet port only after a predetermined high pressure has been established in the pump chamber, the trigger pump dispenser wherein the inlet port (191) is formed in the outer wall of the pump chamber, and the outlet port (192) is formed in the outer wall of the pump chamber.

2. The trigger pump dispenser according to claim 1, wherein the outlet port (192) is closer to the rear wall (193) than the inlet port (191).

3. The valve comprises a valve member (142), which includes an outer valve member (145) and an inner valve member (150), these members being formed separately and connectable to each other, with one of these members (145) providing an inlet valve function and the other member (150) providing an outlet function, and is configured such that during the suction process the piston moves away from the valve (142), thereby creating a vacuum in the pump chamber (190), and the negative pressure causes the sealing lip (146) of the valve to collapse and the inlet port (191) to open. The trigger pump dispenser according to claim 1 or 2, wherein the liquid can enter the pump chamber through the inlet port, the piston is configured to move toward the valve during the pressurizing process, thereby accumulating excess pressure in the pre-compression valve, the sealing lip of the valve is pressed against the outer wall of the pump chamber to seal the inlet port, and when the predetermined high pressure is reached, the valve is configured to close backward, forming a free passage between the outer valve member (145) and the inner valve member (150).

4. The trigger pump dispenser according to claim 3, wherein the predetermined high pressure is defined by the material of the inner member (150) of the valve.

5. The trigger pump dispenser according to any one of claims 1 to 4, wherein the predetermined high pressure is defined by the design of the conical connection between the outer valve member and the inner valve member.

6. The trigger pump dispenser according to any one of claims 1 to 5, wherein the gap formed by the movement of the valve allows the liquid to flow from the pump chamber through the outlet port.

7. A trigger pump dispenser according to any one of claims 1 to 6, comprising a central stop section (154), wherein the opening distance of the valve is determined by the length of the central stop section (154).

8. The trigger pump dispenser according to claim 3, wherein when the pressure of the pre-compression valve falls below the predetermined high pressure, the outer valve member returns to its starting position and closes, sealing the outer portion of the valve, and the connection between the outer valve portion (145) and the inner valve member (150) is closed again.

9. The trigger pump dispenser according to any one of claims 1 to 8, wherein the trigger (60) and the biasing means (65a, 65b) are formed from the same component, and the biasing means comprises a pair of curved spring arms spaced apart from each other.

10. The trigger pump dispenser according to claim 9, wherein the arms (65a, 65b) are joined to the trigger at a hinge point, thereby allowing the arms to move in a hinge manner relative to the trigger when in use.

11. The trigger pump dispenser according to claim 9 or 10, wherein the trigger (60) and the spring arms (65a, 65b) are both formed as a single unit.

12. The trigger pump dispenser according to any one of claims 9 to 11, wherein the arm (65a) and the arm (65b) are substantially the same.

13. The trigger pump dispenser according to any one of claims 9 to 12, wherein the arms (65a, 65b) are substantially J-shaped.

14. The trigger pump dispenser according to any one of claims 9 to 13, wherein the arms (65a, 65b) extend substantially parallel to each other.

15. The trigger pump dispenser according to any one of claims 9 to 14, wherein the spring arms (65a, 65b) are substantially straight along the vertical plane.

16. The trigger pump dispenser according to any one of claims 9 to 15, wherein the spring arms (65a, 65b) are curved in a horizontal plane.

17. The trigger pump dispenser according to any one of claims 9 to 16, wherein the end of the arm (65a, 65b) opposite to the trigger (60) includes a flat surface (75).

18. The trigger pump dispenser according to any one of claims 9 to 17, wherein the end of the arm opposite the trigger (60) has a hook or wedge (80).

19. The trigger pump dispenser according to any one of claims 9 to 18, wherein the arms (65a, 65b) extend from the trigger at one end and are free with at least one degree of freedom at the other end.

20. A trigger pump dispenser according to any one of claims 9 to 19, wherein each arm (65a, 65b) is joined to the trigger at a hinge point, thereby allowing the arms to move in a hinge manner relative to the trigger (60) when in use.

21. A trigger pump dispenser according to any one of claims 9 to 20, wherein the trigger (60) is pulled against a bias provided by the spring arms (65a, 65b), and as the trigger moves progressively, the arms bend or deform and also move hingely relative to the trigger.

22. The trigger pump dispenser according to any one of claims 1 to 21, wherein the trigger (60) is formed from post-consumer recycled (PCR) plastic.

23. The trigger pump dispenser according to any one of claims 1 to 22, wherein the trigger (60) is formed from 20 to 80% PCR-containing material.

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