fig1 depicts a two - chamber ampoule in its initial state . the two - chamber ampoule comprises the housing 1 with a longitudinal axis l , through which housing a bypass 3 is formed . a collar 2 is carried or attached at the end of the housing 1 generally at the discharge end ( the end pointing in the discharge direction a ) of the housing . a septum that serves as the closure 2 of the two - chamber ampoule is located in the collar . the housing contains two pistons 4 , 5 , of which one piston is a closing piston 5 and the other is a separating piston 4 . a front chamber is formed by the end of the housing , the separating piston 4 and the housing 3 , and a product component 9 is located in the front chamber . the product component 9 is , in this case , a solid powder 9 . a second chamber is formed by the separating piston 4 , the closing piston 5 , and the housing 1 . a fluid product component 10 is located in the second , rear , chamber , and serves as a solvent for the product component 9 in the front chamber . both pistons 4 , 5 are arranged in the housing 1 in such a manner that they are displaceable along the axis l . the separating piston 4 displays on its circumferential side two radial grooves 7 . these grooves 7 serve to reduce the friction between the separating piston 4 and the housing 1 . in principle , the separating piston 4 could also be designed without radial grooves 7 . in this exemplary embodiment with grooves , the grooves display a semicircular contour . however , any other advantageous contour could be used . in fig1 , the closing piston 5 and separating piston 4 have the same features , but this is not an absolute requirement for a functional application of the two - chamber ampoule . located in the recesses 7 of the closing piston 5 is , in each case , an o - ring 8 . the o - ring 8 comprises an elastic and / or compressible material . in addition , this material is suitable for forming a seal with the inner side of the housing 1 and the bypass 3 . on the other hand , the material can also be absorbent , so that it is suitable for absorbing fluids to a certain degree . as is shown in fig1 , the o - rings 8 are located in a compressed state in the recesses 7 of the closing piston 5 . to ensure that the o - ring 8 , during the initial state of the two - chamber ampoule , does not come into contact with the product component 10 , at least a part of the circumferential side 6 of the closing piston 5 forms a seal with the housing 1 . fig2 shows the two - chamber ampoule according to the present invention in a state in which the closing piston 5 is located with the o - rings 8 axially in the region of the bypass 3 . through the protrusion of the bypass 3 , it is possible for the o - rings 8 to expand , by virtue of their elasticity , and to occlude and / or at least partially occupy the bypass 3 . through an appropriate selection of the material of the o - rings 8 , a fluid seal is formed between the o - rings 8 and the bypass 3 , which seal prevents the fluid remnants 10 from emerging from the bypass region into a region behind the closing piston 5 , which region is opposite to the discharge direction a ( i . e ., generally at the end of the housing opposite the discharge end ). in addition , the o - rings 8 can be formed of a material that is suitable for absorbing fluids . in this case , the fluid remnants 10 would be absorbed by the o - ring 8 . likewise , a combination of an absorbent material and a sealing material for the o - ring 8 is also conceivable . since two o - rings are used in the closing piston 5 , it can be advantageous to produce , for example , the o - ring 8 closest to the discharge end from a sealing material and the other o - ring 8 from an absorbent material . in this case , were the sealing o - ring 8 to not , in a normal manner , seal off the fluid remnants 10 , then the other o - ring 8 could absorb the overflowing fluid remnants 10 . an exiting of fluid remnants 10 from the bypass 3 is thus prevented . fig3 shows the moment in which the closing piston 5 , together with the o - rings 8 , leaves the axial region of the bypass 3 . to be able to compensate the radial distance between the inner wall of the housing 1 and the bypass 3 , ramp - like oblique bevels are formed as the transitions , which bevels , upon an axial movement of the closing piston 5 in the discharge direction , again press or rather compress the o - rings 8 into the grooves of the closing piston 5 . fig4 shows a piston , e . g ., a closing piston 5 , of a multi - chamber ampoule , which piston has a two - part form . the two parts 15 , 8 are arranged serially or sequentially in the axial direction l , along the axis of the ampoule . the front part 15 of the piston 5 comprises a material that is fluid - impermeable , and forms a fluid seal with the inner wall of the housing 1 . through this , parts of the fluid component 10 that are located in the proximal direction p in front of the part 15 are prevented from moving past this part and reaching the expanding part 8 , when the piston 5 is located outside the region of the bypass 3 . the expanding part 8 of the piston 5 is formed such that , when it moves into the region of the bypass 3 , it expands into and thus occludes the bypass 3 . in addition , the expanding part 8 can consist of a material that , upon contact with the fluid component 10 , begins to swell , i . e . absorb the fluid component . the portion of the expanding part 8 represented in fig4 above the center line l displays , in contrast to the lower part , radially running or extending grooves 7 , which reduce the contact surface of the expanding part 8 with the inner wall of the housing 1 , so that frictional forces during the axial movement of the piston 5 are reduced . fig5 shows a piston 5 that is formed completely of one material , which material , when it is pushed into the region of the bypass 3 , expands and occludes the bypass 3 . since the piston 5 is in constant contact with the product component 10 , the piston 5 must be formed of a material that is not fluid - absorbent . suitable materials are those that , due to their elasticity , rest against the inner wall of the housing in a swelling or sealing manner and can penetrate , expand or extend into the bypass 3 , to occlude or block the latter by occupying at least a portion of it . in one embodiment , a sequence of use or function of an embodiment of a multichamber ampoule and administering device in accordance with the present invention comprises the following steps : in the initial state ( fig1 ) of the two - chamber ampoule , the fluid solvent 10 is located between the closing piston 5 and the separating piston 4 . the product component 9 to be dissolved is located between the separating piston 4 and the collar 2 . through application of a force to the closing piston 5 , the latter is moved , during the mixing process , in the discharge direction a . in consequence of the incompressibility of the solvent 10 , the movement is transferred to the separating piston 4 , until the latter is axially located with its entire length in the region of the bypass 3 . for this , in some embodiments , the separating piston 4 has a shorter axial length than the bypass 3 . since the solvent 10 now flows past the separating piston 4 via the bypass 3 to the front product component 9 and can thus mix with it , the separating piston 4 remains stationary until the closing piston 5 strikes against the separating piston 4 . at this moment , the mixing process is completed . if the closing piston 5 is moved further in the discharge direction a , then it pushes the separating piston 4 likewise in this direction . this moment represents the beginning of the discharging process of the product mixture 9 . through the axial movement of the piston 5 in the discharge direction a , the closing piston 5 is moved axially into the region of the bypass 3 . in the region of the bypass 3 , the o - rings 8 are no longer compressed by the housing 1 , so that , due to their elastic material , the o - rings 8 expand and move into the bypass 3 . the o - rings 8 now prevent the reflux of fluid remnants 10 from the bypass 3 against the discharge direction , since the o - rings 8 form a sealing and / or fluid - absorbing element . for completing the discharging of the product mixture 19 , the closing piston 5 is further pressed in the discharge direction a , so that it leaves the region of the bypass 3 ( fig3 ). by means of the ram - like element 11 , which acts as an oblique plane , the o - rings 8 , through the axial movement of the closing piston 5 , are radially compressed back into the recess 7 and are pre - stressed . the o - rings 8 are now located completely in the region of the housing 1 , i . e . they are no longer in the region of the bypass 3 . for completing the discharging of the product mixture 19 , the closing piston 5 is pressed in the axial direction a until the forward side of the separating piston 4 abuts or lies against the discharge end of the housing 1 . embodiments of the present invention , including preferred embodiments , have been presented for the purpose of illustration and description . they are not intended to be exhaustive or to limit the invention to the precise forms and steps disclosed . obvious modifications or variations are possible in light of the above teachings . the embodiments were chosen and described to provide the best illustration of the principles of the invention and the practical application thereof , and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated . all such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth they are fairly , legally , and equitably entitled .
a multi - chamber ampoule including a housing with a longitudinal axis , at least one bypass operably associated with the housing , at least one front and one rear piston both of which can engage with the housing in a sealing manner outside the vicinity of the bypass and both of which may be displaced along the longitudinal axis , wherein the rear piston includes at least one material which can project into the bypass when the rear piston is in the region of the bypass .