DE2723321C2 - Vapor barrier for a piston metering pump - Google Patents

Description

position shown, wherein the cleaning connection 6 is closed and the sterilization via the steam inlet IaDöTinung 10 takes place.

As can be seen from the illustration, the outside diameter is the hollow piston rod 8 is smaller than the inner diameter of the working stroke 2 in the housing forming cylinder, v / as ensures that the vapor forming the vapor barrier from the vapor overflow openings 11 can also exit and go up into the rinsing room if 5 when both pistons 3.4 move in the area of the working stroke section 2.

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1 sheet of drawings

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Claims (2)

Patent claims: 1 vapor barrier for a piston metering pump to keep the piston rod sterile behind the piston, which is surrounded by a jacket containing a pamprein- and outlet, characterized in that the piston consists of a metering piston (3) and a control and locking piston (4) , and the dosing piston (3) has a hollow piston rod (8) which surrounds the piston rod (9) of the control and locking piston like a jacket and contains the steam discharge opening (10) at the end remote from the dosing piston and a steam overflow opening (11) directly above the dosing piston, to connect the interior space (7) of the piston rod JS) with the space formed by the outer surface of the hollow metering piston rod (8) and the cylinder (1). 2. Vapor barrier according to claim 1, characterized that above the working stroke of the piston (3, 4) in the cylinder a flushing space ip, is arranged whose diameter is larger than the diameter of the cylinder (1). The invention relates to a vapor barrier for a piston metering pump according to the preamble of the patent claim ^C Such vapor barriers are used to prevent smear infections from iler Ve; To avoid external atmosphere containing impurities in the pump or valve interior, in which sterile masses to be pacified are dosed. Vapor barriers of the type mentioned are known from DE-OS 22 11 117. The metering piston or pistons are in an open cylinder arranged on the back of the piston against a buffer space that can be flushed with superheated steam housed on the housing, which can be flushed separately with superheated steam, for the ends of the Piston rods are provided. For the suction and the dosing output of the product are outside the Buffer space arranged in front of the actual working space rotary valve with adapted housings, which thus are not accessible to hot steam purging. Furthermore, according to DE-OS 21 63 097, a metering pump known, in which the metering piston and the control and closing piston are reset in the steam purging chambers and can be rinsed there with steam for sterilization and cleaning. For one all the time effective vapor barrier during operation, this filling pump is not suitable because the control and Closing piston moves with its piston rod in the Fülirnassenzuführraum and this with the Dosierkolbcnraum communicates. The invention is accordingly based on the object of a vapor barrier of the type mentioned at the outset to improve that a permanently effective for the two piston rods even during operation Vapor barrier to prevent smear infection is guaranteed. This valve is equipped with a vapor barrier in piston metering pumps of the type mentioned in the introduction solved by the features listed in the characterizing part of the patent claim. In an advantageous further development, it is provided that that above the working stroke of the piston in the cylinder, a flushing chamber is arranged, the diameter of which is larger than the diameter of the cylinder, which means that in a cleaning phase without having to mount the pump to have to be able to flush the pistons and the entire interior of the cylinder. The combination according to the invention of the features listed in the identifier ensures that on the one hand the piston rod of the control and closing piston during operation, since this extends through the interior of the piston rod of the metering piston can be flushed with steam, but also the hollow piston rod of the dosing piston from the outside, since the steam can get from their interior into the steam purging chamber, for which the stipulation cr-1-jrderlich is also required is that the hollow piston rod must have a smaller outer diameter than the inner diameter of the cylinder space in the area of the actual working stroke. O ₀ reference is made to a filling pump according to DE-PS 27 23 320 of the same rank, in the case of the Stcu- __. _ünc j C ₀ UIj ₅ Ru ₀ IiJg _{n provided} with mass passage channels and the mass feed line connection is arranged in the lower travel range of the control and closing piston. wherein the control and closing piston and the metering piston are arranged in the cylinder so that they can be controlled independently of one another, coaxially one behind the other, and the piston rod of the control and closing piston extends through the piston rod of the metering piston. In the design of the vapor barrier according to the invention, metering and closing pistons work in normal operation in the area of the working stroke distance below the steam purging space. The back of both pistons has steam applied to them, and the amount of steam is regulated in such a way that a condensate of sterile water is created, the drainage of which is ensured by the cleaning drain. During the actual cleaning, during which the both pistons free-standing in a known manner in the steam purging space above the actual working stroke and the entire pump is cleaned in a continuous cycle without dismantling the pump the steam connection can be blocked, which is also connected to the cleaning circuit will. When steaming (sterilizing) the dosing pump, the cleaning connection is closed and the entire Pump sterilized via the steam connection. The inventive vapor barrier for the Kolbcrr-50 metering pump is described below with reference to the graphic representation of a highly schematic exemplary embodiment explained in more detail. In the schematic representation, 1 is the cylindrical Housing designated, its lower part with 55 Filling nozzle and mass supply connection not shown isl. The dosing pistons move during normal filling operation 3 and the control and closing piston 4 only within the working stroke distance 2. However, the piston rods 8 9 remain exposed to the steam supplied through the steam inlet opening 10 on the hollow piston rod 8 from this through the steam overflow opening 11 also into the washing area 5 and thus to the outer surface the hollow piston rod 8 can reach. Are the pistons 3, 4 in the rinsing area 5, as shown, b-i started up..so the whole pump can be flushed or be steamed from the inside without having to dismantle any individual parts. During sterilization, the pistons 3, 4 remain in the