FR2636880A3 - Fluid-distributing device intended for the temperature-control (thermoregulation) of moulds for the working of plastics or metals - Google Patents

Abstract

Fluid-distributing device intended for the temperature-control (thermoregulation) of moulds for the working of plastics or metals, comprising a tank 5 for the said fluid and to which tank are connected a pipe A sending the fluid towards the mould and a pipe R for returning the fluid coming from the mould, characterised in that it includes a vacuum pump 17 fixed to the return pipe R containing the fluid coming from the mould, the said pipe R being connected to the top of the said tank 5 via a box 12 having two compartments 13, 14 which separate the gaseous or gas elements from the liquid, and in the said tank 5 is provided a coil heat exchanger 8 in which a refrigerant fluid circulates, and immersed heating (electrical resistance) elements 11 which are used in alternation with the coil exchanger.

Description

DEVICE WITH FLUID DISTRIBUTION FOR THERMOREGU-
LOTION OF MOLDS FOR WORKING PLASTIC MATERIALS OR
METALS"
The invention relates to a device with fluid distribution intended for the thermoregulation of molds used in injection molding machines for plastics or metals, which device is fitted with a pump which can suck the fluid from the mold in question to channel it. first in a tank for heat exchange with another fluid intended for cooling and then from said tank to said mold. The tank is equipped with devices which separate the ga from the liquid fluid, send the fluid intended for cooling and possibly an auxiliary heat exchanger.

 There are already thermoregulatory installations using a liquid fluid, for example water or oil, to control and / or maintain the molds intended for working with plastics at a predetermined operating temperature. These installations circulate the fluid in a tank to heat it, to make a possible exchange of heat or to mix it with another cold fluid.

 Known devices generally operate under pressure, which has various drawbacks and disadvantages. Note that, in such operating conditions, the connections of the return and return tubes of the thermoregulation liquid must be perfectly sealed, otherwise liquid will be lost. Sealing also requires the use of gaskets, collars, etc., which complicates the work and lengthens the assembly time.

 On the other hand, possible cracks in the mold, wear of the seals, perforation or rupture of the tubes, loosening of the caps, etc., cause a dispersion of the liquid, which causes the stopping of the use of molds and serious risks of burns for operators, burns due to the violent projection of hot liquid.

 In addition, to switch from the distribution of the hot liquid to the distribution of the cold liquid, the tank must be emptied each time, resulting in a continuous change of liquid in the molds and therefore a greater possibility of lime deposition when, as this is often the case, the liquid used is water. Such an obligation to empty the tank and pour the hot liquid each time one passes from the hot liquid to the cold liquid also prevents the use of special liquids or water with additives as would be desirable.

 Finally, pressure thermoregulators have the disadvantage of not being able to eliminate any gases or vapors that form in the mold, consequently these gases or vapors disperse in the mold thus causing production waste.

 The object of the present invention is to provide a device intended for thermoregulation of molds for working with plastics or metatrx, which device operates under vacuum or aspiration and thus makes it possible to completely eliminate the drawbacks and disadvantages noted above. .

 Another object of the invention is to provide a device which is safer and more flexible to the extent that any liquid, special or with additives can be used, since this device does not provide for flow or dispersion. liquid.

 To do this, the present invention relates to a vacuum device for thermoregulation of the molds used in injection machines according to claim 1 /.

 We will provide a better illustration of an example of practical application as well as other objects and advantages of the invention in the following description which is based on the appended drawings and in which FIG. 1 shows the device R1 of the exterior, in perspective, FIG. 2 shows the hydraulic diagram of said device for thermoregulation of a mold.

 In said drawing, (1) generally indicates a mold which contains, as is known, conduits (2) in which circulates a thermoregulatory fluid (3) distributed by a distribution device (4) and this fluid is conveyed by a forward tube (A) and a return tube (R). Said fluid is generally a liquid such as water but can also be any other suitable liquid with or without additives.

 Thanks to the invention, the dispensing apparatus (4) comprises - cf. Fig. 2 - a reservoir (5) intended to receive and contain the thermoregulatory fluid (3) and the level of which is automatically controlled by a float (6) connected to an electrovalve (7) fixed on a tube (7 ') which sends the fluid in the reservoir (5) during its initial filling and each time it is possibly useful to add more. In addition, provision is made to provide the reservoir with a coil heat exchanger (8) in which circulates a refrigerant fluid coming from a refrigerating appliance (9) in order to establish a heat exchange with the fluid (3) contained in The reservoir.

The coil heat exchanger (8) is supplied with an electrovalve (10) so as to maintain the fluid (3) in the tank at a pre-established operating temperature in order to ensure thermoregulation. correct mold (1). Provision is also made to provide the tank with immersed electrical resistors (11) to initially heat the fluid (3) or to maintain its temperature.

 A box (12) is fixed on the top of the tank (5).

This box has two compartments (13 - 14) separated by a vertical partition (15) and both communicating from below with the interior of the tank (5).

 The return tube (R) containing the fluid from the mold is connected to the first compartment (13) of said box (12), while the go tube (A) containing the fluid intended to pass into the mold (1) is connected side to # tank (5). In this way, the fluid coming from the mold (1) - fluid which may or may not contain aeriform or gaseous elements - arrives in the reservoir (5) after having entered the first compartment (13) to then be distributed in the mold by means of the go pipe (A).

 The air or gas element present in the tank (5) passes into the second compartment (li) to be discharged into the atmosphere by means of a tube (16) fixed to the top of said compartment.

 Arranged thus, the box (12) therefore acts as a separator between the liquid elements and the gaseous elements.

 On the return tube (R) connected to the mold (1) a suction pump (17) is fixed which controls the circulation of the thermoregulatory fluid from the reservoir to the mold and vice versa.

 On said return tube (R) one can also fix an auxiliary heat exchanger (18) supplied by a circuit (19) by means of the same refrigerant which supplies the coil exchanger (8) of the tank (5).

 The reservoir (5) and the box (12), the pump (17) and the other components are combined in a carcass (20) - cf.

 Fig. 1 - which comprises - on the front of a switchboard (20 ') with the control instruments, - on one side of the manifolds with fixings (21-22) for the connection of the outward (A) and return (R) tubes respectively ) from the thermoregulatory fluid to the mold.

 The device works mainly in vacuum which contributes above all - to eliminate the losses of fluid in the event of crack of the mold itself, the ruptures of joints or tubes, etc. and, - to facilitate the assembly of the various components since it is no longer necessary to have a maximum seal and that the collars no longer have any reason for being.

 The circuit also allows the gases to be sucked in and away from the mold, which reduces the production waste due to these gases.

The thermoregulating fluid (3) circulates in a closed circuit and must never be emptied from the tank even when a hot fluid and a cold fluid have to be used alternately. It follows the possibility of using special fluids which do not deposit lime which is an advantage for better operation and greater security of all devices.

Claims (5)

REN ICATIONS  1 / Device with fluid distribution intended for the thermoregulation of molds for working plastics or metals comprising a reservoir (a) for said fluid and to which reservoir are connected a tube (A) which sends the fluid to the mold and a tube (R) for return of the fluid from the mold, characterized in that it comprises a vacuum pump (17) fixed on the return tube (R) containing the fluid from the mold, said tube (R) being connected at the top of said tank (5) by means of a box (12) with two compartments (13 -14) which separate the aeriform or gas elements from the liquid, and in said tank (5) there is provided a heat exchanger with coil (8) in which a refrigerant circulates, and immersed electrical resistors (11) which are used alternately with the coil exchanger.  2 / Device according to claim 1 / characterized in that an auxiliary heat exchanger (18) supplied with the same refrigerant which supplies the coil exchanger (8) which is located on the return tube (R) in said tank (5).  3 / Device according to claims 1 / and 2 / characterized in that said box (12) consists of two compartments (13 - 14) separated by a partition (15) and both communicating with said tank; the fluid coming from the mold in the return tube (R) passes into one of these compartments (13) while the air-forming element or gas which forms in the reservoir (5) is collected in the other compartment (14) and is evacuated by means of a tube connected to this same compartment.  4 / Device according to the preceding claims characterized in that the fluid flows from the reservoir to the mold and vice versa, in a closed circuit and in a vacuum condition.  5 / Device according to the preceding claims characterized in that the outgoing tubes (A) and return (R) are connected respectively to the tank and to the pump by means of control valves.