CLIAMS:1. A system for manufacturing gelatin free hard shell seamless capsules comprising:
a) a tank for shell forming liquid (1) and core forming liquid (2) fitted with suitable heating arrangement;
b) double concentric nozzle (3) is connected to said tank (1, 2) via insulated/jacketed mass transfer lines (4, 5) to maintain the temperature of the content flowing through said transfer lines
c) compressed air pumps (6, 7) helps in the movement of tank content;
d) the compressed air passes through pressure reducing valve (8 & 9) before entering to the tank (1, 2).
e) proportional integral derivative (PID) controllers (10, 11) are there to control the pressure of the compressed air;
f) An agitator (12) is fixed in the tank containing shell forming liquid to agitate the thick shell forming liquid continuously to ensure heat distribution;
g) temperature sensors (13, 14) are mounted on both the tanks to measure the temperature of the content;
h) a precision solenoid valve (15) is fit to the tank containing shell forming liquid;
i) a band heater (16) is surrendered around the double concentric nozzle (3) to heat the nozzle assembly;
j) spherical droplets (17) thus produced immerse into the cooling liquid cylinder (18) and solidifies.
k) a chiller (19) is fit with recirculation pump;
l) an online strainer (20) helps in straining the capsules formed;
m) the strained capsules are collected and dried in a suitable dryer;
n) a vibration induction device (21) is mounted on the concentric nozzle which is controlled through a control panel (22);
wherein height of the nozzle from the surface of the cooling liquid is set between 5-15 cm.

2. A method of preparing the gelatin free hard shell seamless capsules comprising the steps of:

a. passing the shell forming liquid through conduit (4) at a given temperature, which ends at the outer nozzle of the concentrically aligned double nozzle (3);
b. passing the core forming liquid through conduit (5) at a given temperature, which ends at the inner nozzle of the concentrically aligned double nozzle (3);
c. extruding both the shell and core forming liquid through the concentrically aligned double nozzle to form a spherical shaped capsule (17);
d. dropping the capsule (17) into the cooling oil cylinder (18) placed at a height from the tip of the concentrically aligned double nozzle (3) at desired vibration frequency;
e. straining capsule (17) through a strainer (20) and collecting the capsules (17);
f. drying the capsules to attain the acceptable moisture level, not exceeding 20%.
3. The method as claimed in claim 2, wherein said shell forming liquid melt temperature ranges from 90 to 94°C.
4. The method as claimed in claim 2, wherein said core forming liquid temperature ranges from 38 to 42°C.
5. The method as claimed in claim 2, wherein said concentrically aligned double nozzle temperature ranges from 90 to 94°C.
6. The method as claimed in claim 2, wherein said shell forming liquid flow rate ranges from 10 to 200 mbar.
7. The method as claimed in claim 2, wherein said core forming liquid flow rate ranges from 20 to 1000 mBar.
8. The method as claimed in claim 2, wherein said cooling oil temperature ranges from 10 to 15°C.
9. The method as claimed in claim 2, wherein said vibration frequency ranges from 10 to 500 Hz.
10. The method as claimed in claim 2, wherein the capsules are dropped into the cooling oil cylinder from a distance of 5-15cm in height.
11. The method as claimed in claim 2, wherein said spherical shaped capsules size ranges from preferably, 1-10 mm in diameter, and most preferably 3.4-3.6mm in diameter.

12. The gelatin free hard shell seamless capsules of any one of the preceding claim which is used in tobacco and/or nicotine containing combustible products such as cigarettes, filters with capsules attached to the cigarettes and so on.
,TagSPECI:Field of the Invention
The present invention relates to hard shell seamless capsules, more particularly the present invention relates to a system and a process to manufacture gelatin free hard shell seamless capsules.

Background and the Prior Art
The challenges associated with gelatin free hard shell seamless capsules making process is the shell forming material, made by a composition containing vegetable based polymer material, which melts at high temperature and solidifies quickly even with little drop in temperature. It is also found that the viscosity of the shell forming material is highly dependent on temperature and any change in temperature affects the viscosity which has a direct bearing on the quality of the capsules. It is seen that maintenance of accurate flow rate of shell forming liquid and core forming liquid is highly essential to get good quality capsules and to get desired production rate.

To effectively capture both the shell and core forming liquid to form a seamless spherical shaped capsule, cong centrically aligned double nozzle is generally preferred. However, most of the prior art teach nozzles that are totally or partially immersed in the cooling liquid (e.g. US Pat. No. 7112292, US Pat. No. 4422985, US Pat. No. 6174466, US Pat. No. 2911672) which pose major disadvantages.

US 7112292 discloses a method of manufacturing a spherical seamless capsule formed by encapsulating a filler material such as a medicine with a capsule shell material such as gelatin.

US Pat No’ 292 also talks about keeping the tip of the concentrically aligned nozzle at a height from the surface of the cooling liquid. But the prime intention of that is to produce gelatin based capsules without irregularities and to do that the inventors of the invention have optimized the height of the tip of the nozzle and claims that the optimum height is 0.5 to 3 time of the outer diameter of the capsules. The patent also discloses that the composting flow of liquid breaks into capsules inside the curing liquid and not in air.

The main objective of our invention is a system and method to handle shell forming material which solidifies quickly and thus cannot be used to make capsules with the system describes on US pat No’292.

Since the present invention forms the capsule in air rather than immersing the composting liquid flow in curing liquid, the height has been optimised.

US 4422985 discloses a method for encapsulation of a liquid or meltable solid material, comprises the steps of forming a jet of a material to be encapsulated, simultaneously forming a coaxial jet of a capsule-forming material surrounding the jet of the material to be encapsulated, forming a coaxial jet of a heated circulating liquid surrounding the coaxial composite jet of the capsule-forming material and the material to be encapsulated, introducing the resultant coaxial triple jet into a flow of a cooling liquid to form capsules composed of a core of the material to be encapsulated and a capsule or coating film of the capsule-forming material. The heated circulating liquid has a temperature close to or higher than that of the capsule-forming material.

US ‘985 talks about an arrangement where the tip of the nozzle is immersed into the curing liquid. Since this is a disadvantage for shell forming liquid having high melting point, the inventors have proposed a method of supplying a flow of hot liquid along with the composting liquid flow leaving the nozzle to prevent solidification. This is disadvantages as maintaining the temperature of both the liquid (curing liquid and hot liquid) is impossible for extended period of time. This kind of arrangement also sees fusion of multiple capsules and defects.

US 6174466 Method for the production of seamless capsules in which capsule forming material passes from a heated carrier fluid to a cooled carrier fluid during formation and solidification of the capsules.

The inventors of the US ‘466 realized the disadvantages associated with a capsule manufacturing system where the tip of the nozzle is immersed in the cooling liquid for a shell forming solution which melts at higher temperature and solidifies quickly.

To overcome the disadvantages, the inventors have proposed a design of the system to keep the nozzle away from the cooling liquid. The inventors disclose a system where the nozzle is immersed into hot liquid. The composting liquid flow immerses into the hot liquid and breaks into small droplets and then transports to the cooling liquid duct for solidification. The inventors disclose the ratio of the flow rate of the hot and cooling liquid to avoid mixing of the same.

The inventors of the present invention found that such limitation of the ratio of hot and cooling liquid in the prior art is disadvantages for a system meant for higher production rate. Higher production rate requires higher flow rate of the cooling liquid to remove the excess energy from the capsule surface. Unlike the prior arts, the cooling oil does not require to put additional force to push the tender capsules against gravity. The capsules are getting discharged from the cylinder by gravity itself. This is what contextually we mean by energy efficient. This eliminates the chances of deformation or rupturing of capsules.

The inventors of the US Pat No: 6174466 realized the disadvantages associated with a capsule manufacturing system where the tip of the nozzle is immersed in the cooling liquid for a shell forming solution which melts at higher temperature and solidifies quickly.

To overcome the disadvantages, the inventors have proposed a design of the system to keep the nozzle away from the cooling liquid. The inventors discloses a system where the nozzle is immersed into hot liquid. The composting liquid flow immerse into the hot liquid and breaks into small droplets and then transports to the cooling liquid duct for solidification. The inventors disclose the ratio of the flow rate of the hot and cooling liquid to avoid mixing of the same.

The inventors of the present invention found that such limitation of the ratio of hot and cooling liquid in the prior art is disadvantages for a system meant for higher production rate. Higher production rate requires higher flow rate of the cooling liquid to remove the excess energy from the capsule surface.

The design of the system discloses by the inventors of the present invention does not require additional accessories such as additional reservoir to heat second liquid and transport through the cylinder, flow controller to maintain laminar flow of both the liquid, etc.

Rather, the inventors of the present invention found that just by placing the nozzle at a height 5-15 cm away from the surface of the cooling liquid can overcome the disadvantages associated with processing of high temperature shell forming liquids.
The design of the system discloses by the inventors of the present invention does not require additional accessories such as additional reservoir to heat second liquid and transport through the cylinder, flow controller to maintain laminar flow of both the liquid, etc.

Rather, the inventors of the present invention found that just by placing the nozzle away from the surface of the cooling liquid can overcome the disadvantages associated with processing of high temperature shell forming liquids.

Further, none of the prior art teaches the cooling liquid cylinder which is user friendly, practical and energy efficient (US Pat. No 4251195, 7112292). There are no prior art which teaches an energy efficient, economical system to make gelatin free hard shell seamless capsules, preferably with a viscosity ranging from preferably 300-900 cps, more preferably 400-800 cps, and most preferably 400-600 cps.

Hence there is a need for a system and method which can produce gelatin free hard shell seamless capsules with shell forming polymer composition having high melting temperature and tendency to solidify quickly with little drop of temperature.
Object of the present invention
An object of the present invention is to overcome the drawbacks of the prior art:

Another object of the present invention is to provide a system and method to manufacture seamless capsules which melts at higher temperature and solidifies quickly with little drop of temperature.
Yet another object of the present invention is to provide a user friendly, energy efficient and economical system to make gelatin free hard shell seamless capsules.
Another objective of the present invention is to provide a system that can produce capsules having spherical shape, even size and free from any discernible defects with higher production rate i.e. at least 60 capsules per minute.

Yet another objective of the present invention is to provide system to manufacture seamless capsules with vegetable based shell forming material.

Another objective of the present invention is to provide a system to melt the shell forming material. The significance of the system is to melt the shell forming material at higher temperature for a longer time but at the same time it should not denature the properties of such materials used.

Summary of the present invention
An aspect of the present invention is to provide a system for manufacturing gelatin free hard shell seamless capsules comprising:

a. a tank for shell forming liquid (1) and core forming liquid (2) fitted with suitable heating arrangement;
b. double concentric nozzle (3) is connected to said tank (1, 2) via insulated/jacketed mass transfer lines (4, 5) to maintain the temperature of the content flowing through said transfer lines
c. compressed air pumps (6, 7) helps in the movement of tank content;
d. the compressed air passes through pressure reducing valve (8 & 9) before entering to the tank (1, 2).
e. proportional integral derivative (PID) controllers (10, 11) are there to control the pressure of the compressed air;
f. An agitator (12) is fixed in the tank containing shell forming liquid to agitate the thick shell forming liquid continuously to ensure heat distribution;
g. temperature sensors (13, 14) are mounted on both the tanks to measure the temperature of the content;
h. a precision solenoid valve (15) is fit to the tank containing shell forming liquid;
i. a band heater (16) is surrendered around the double concentric nozzle (3) to heat the nozzle assembly;
j. spherical droplets (17) thus produced immerse into the cooling liquid cylinder (18) and solidifies.
k. a chiller (19) is fit with recirculation pump;
l. an online strainer (20) helps in straining the capsules formed;
m. the strained capsules are collected and dried in a suitable dryer;
n. a vibration induction device (21) is mounted on the concentric nozzle which is controlled through a control panel (22);
wherein height of the nozzle from the surface of the cooling liquid is set between 5-15 cm.

another aspect of the present invention is to provide a method of preparing the gelatin free hard shell seamless capsules comprising the steps of:

a) passing the shell forming liquid through conduit (4) at a given temperature, which ends at the outer nozzle of the concentrically aligned double nozzle (3);
b) passing the core forming liquid through conduit (5) at a given temperature, which ends at the inner nozzle of the concentrically aligned double nozzle (3);
c) extruding both the shell and core forming liquid through the concentrically aligned double nozzle to form a spherical shaped capsule (17);
d) dropping the capsule (17) into the cooling oil cylinder (18) placed at a height from the tip of the concentrically aligned double nozzle (3) at desired vibration frequency;
e) straining capsule (17) through a strainer (20) and collecting the capsules (17);
f) drying the capsules to attain the acceptable moisture level, not exceeding 20%.

Brief Description of Accompanying Drawings
Figure-1: Schematic design of apparatus illustrating formation of capsules
Figure-2: Schematic design illustrating the effect of nozzle height on quality of capsules
Figure-3: Schematic design of the tank containing shell forming liquid
Figure-4 : Schematic design of the cooling liquid cylinder
Figure-5: Schematic design of the shell forming material melting system

Detailed Description of the Invention
The present invention provides a system and a process to manufacture hard shell seamless capsules where the shell forming material melts at higher temperature and solidifies quickly with slight decrease in temperature.

The terms used in the specification has been defined as under.
“Good quality capsule” refers to capsule of substantially spherical shape, even sized and free from any discernible defects with higher production rate i.e. atleast 60 capsules per minute.

The term “even sized” in this invention refers to capsules have diameter in the desired range. The desired diameter range of the capsules is (mean diameter ±0.1 mm).

The term “discernible defects” in this invention refers to any perceivable defects such as uneven size which can affect the end usage of the capsules.

The term “substantially spherical shape” in this invention refers to the ratio of the minor to major axis of the capsule. To be substantially spherical, the capsule should have the number equal to or more than 96 %.

“Shell forming material” can be defined as “shell polymer” and the both the terms are interchangeable, which made up of any suitable material forming the shell i.e. the outer layer of the capsules. The shell forming material of the present invention is a gelatin free vegetable based material. The shell forming material contains atleast carrageenan as base material. The shell forming material dissolves in water at higher temperature and solidifies quickly with little drop of temperature.

“Core forming material” is a hydrophobic liquid, semiliquid or emulsion, which is the content of the seamless capsules. The core forming material may also contain actives, flavors or some other specialty chemicals.

Other specialty chemical in this invention refers to any other chemical that can be used for customized end use, such as, chemical to impart heating and cooling effect, etc.

“Desired flow rate” depends on the size of the capsules produce and vibration frequency. The desired flow rate of shell and core forming liquid depends upon the required size of the capsules and production rate i.e. vibration frequency. With the increase of vibrating frequency, to keep the size contestant, higher flow rate of shell and core forming liquid is expected.
A preferred embodiment of the present invention provides a system as illustrated in Figure 1 wherein, the reference number 1 & 2 indicates the tank for shell forming liquid and core forming liquid respectively. The tanks are fit with suitable heating arrangement to maintain the temperature of the content in the tank precisely. The tanks are connected to the double concentric nozzle (3), via jacketed mass transfer lines (4, 5). The transfer liens (4, 5) are insulated/ jacketed to maintain the temperature of the content flowing through the lines. The content of the tank is pushed by the help of compressed air pumps (6 &7). Peristaltic pump can also be used instead of compressed air to push the core liquid from the tank containing core liquid. The compressed air passes through pressure reducing valve (8 & 9) before entering to the respective tank. Proportional integral derivative (PID) controllers (10 & 11) are there to control the pressure of the compressed air. An agitator (12) is fixed in the tank containing shell forming liquid to agitate the thick shell forming liquid continuously to ensure heat distribution. Temperature sensors (13, 14) are mounted on both the tanks to measure the temperature of the content. A precision solenoid valve (15) is fit to the tank containing shell forming liquid. The double concentric nozzle (3) is surrounded by a band heater (16) to heat the nozzle assembly. The spherical droplets (17) thus produced immerse into the cooling liquid cylinder (18) and solidifies. The cooling liquid in the cooling liquid cylinder is a hydrophobic liquid, preferably mineral oil or light paraffin. The temperature of the cooling liquid is maintained at below 15 °C. A chiller (19) is fit with recirculation pump to maintain the desired temperature of the cooling liquid. The capsules thus formed get strained through an online strainer (20). The strained capsules are collected and dried in a suitable dryer. A vibration induction device (21) is mounted on the concentric nozzle. The vibrator is controlled through a control panel (22).
In another embodiment of the present invention there is provided a method for the preparation of the gelatin free hard shell seamless capsules comprising steps of:
a. passing the shell forming liquid through conduit (4) which ends at the outer nozzle of the concentrically aligned double nozzle (3);
b. passing the core forming liquid through conduit (5), which ends at the inner nozzle of the concentrically aligned double nozzle (3);
c. extruding both the shell and core forming liquid through the concentrically aligned double nozzle to form a spherical shaped capsule (17);
d. dropping the capsule (17) into the cooling liquid cylinder (18) placed at a predetermined height of 5-15 cm from the tip of the concentrically aligned double nozzle (3);
e. straining capsule (17) through an online strainer / separate strainer (20) and collecting the capsules (17); and
f. drying the capsules to attain the acceptable moisture level.
The capsules of the present invention are spherical in shape, even sized capsules and the diameter of the same ranges from preferably between 1mm-10mm and most preferably between 3.4 - 3.6mm.
While extruding both the shell and core forming liquids from the orifice of the concentrically aligned double nozzle, the shell forming liquid encapsulates the core forming liquid and thus seamless capsule is formed.

The inventors of the present invention maintain the temperature of the shell forming liquid at 85-98 °C and the temperature of the core forming liquid at 25-45 °C.

The shell forming composition in the present invention comprising gelatin free biopolymer based material. The shell forming composition contains atleast carrageenan along or in combination with other gelatin free biopolymers selected from pectin, alginates, locust bean gum, pullulan, modified starches, cellulose, cellulose derivatives, gellan gum, guar gum or guar gum derivatives or their mixtures thereof. However this is not limited only to the above mentioned composition but also applies to any composition that melts at higher temperature and solidified quickly with little drop of temperature.

The shell forming composition also contains gelling material which is water soluble mono-valent or di-valent metal salts. The example of the metal salt, and is not limited to, is potassium chloride, calcium chloride and the like. Potassium chloride can be added alone or in combination with other metal salts.

The shell forming composition also contains moisture retaining agent. The example of moisture retaining agent, and is not limited to, is propylene glycol.

An optional colouring agent can also be used for aesthetic look and differentiation.

Figure 2 provides an illustration of the effect of nozzle height on quality of capsules. It provides a design of a system wherein the nozzle is placed at a height (5-15 cm) from the surface of the cooling liquid. The spherical droplets extruded from nozzle solidifies upon touching the cooling liquid in the cooling liquid cylinder.

The inventors of the present invention have observed that the height of the orifice of the nozzle from the surface of the cooling liquid (Figure-2) plays an important role in deciding the quality of the capsules. Studies have shown that good quality capsules are formed if the height is kept in between 5-15 cm. If the height is more than 15 cm, the capsules deform because of the impact. The inventors of the present invention also observed that if the nozzle is placed at height lower that 5 cm, the extruded liquid column directly enters into the cooling liquid and solidifies before separating as spherical droplets and therefore capsules are not formed.

Viscosity parameters:
The inventors of the present invention have observed that the viscosity of the shell forming liquid is highly critical to manufacturing good quality capsules. The inventors have maintained the viscosity of the shell forming liquid in the range of 300-900 cps, more preferably 400-800 cps, and most preferably 400-600 cps.

The present invention provides a design of an apparatus to maintain/adjust the viscosity of the shell forming liquid by heating/cooling the shell forming liquid in the tank containing shell forming liquid, shell forming liquid transfer line and at nozzle to ensures maintenance of desired viscosity and thus production of good quality capsules.

The present inventors have found that the flow rate of both the shell forming liquid and core forming liquid is very critical to get capsules with good quality and desired production rate. Even slight change in flow rate of the liquid changes the shape and size of the capsules. The inventors of the present invention provide a design of the apparatus which can maintain the flow rate of the shell forming liquid precisely to ensure desired production rate and quality of the capsules.

Figure-3 illustrates the schematic design of the tank (1) containing shell forming liquid. The tank is equipped with heating arrangement (2) to adjust the temperature. Three flight stirrers (3) are fixed inside the tank for mixing and effective heat distribution in the viscous liquid. The temperature sensor (4) senses the temperature of the liquid. Compressed air (5) is used to push the viscous liquid to the nozzle. A pressure reducing valve, PRV (6) is used to reduce the pressure of the compressed air to the desired level. Digital PID controller (7) is fit to control the input pressure precisely. The compressed air pushes the liquid to the nozzle through the mass transfer line (8).
The inventors of the present invention have found that during the manufacturing of capsules, steam is getting generated in the tank containing shell forming liquid which leads to increase of pressure in the tank resulting in uncontrolled flow rate which leads to the production of capsules of inferior quality. To overcome this processing issue, the inventors of the present invention have designed a tank for shell forming liquid fit with solenoid valve and PID controller (Figure-3).

A high precision solenoid valve (9) is mounted on the tank. The solenoid valve is designed in such a way that it bleeds for few milliseconds in every second to release the steam generated and thus excess pressure. This allows maintaining the pressure in the tank which is highly required for manufacturing good quality capsules. The inventors of the present invention have found that the system can produce good quality capsules even with ± 10 % variation of input pressure (compressed air). Further please provide a board range of the flow rate which is critical to maintain for desired production rate and quality of the capsules.

It is important to have a cooling oil cylinder which is user friendly, energy efficient with practical applications. Conventionally, cooling liquid was used to push the capsules against the gravity before discharge. The inventors of the present invention have found that pushing capsules against gravity before getting the capsules discharged from the cylinder requires higher flow rate of the cooling liquid. The inventors have also observed that higher flow rate deforms the tender capsules (due to shear force) and in extreme case it can rupture the tender capsules as well.

The design of the cylinder is detailed in Figure-4.

Figure-4 illustrates a concentrically aligned jacket (1) at the top of the cooling cylinder. The cooling oil coming from the chiller (2) pours into the jacket and flow down-wards along the cooling cylinder (3) and comes out of the chute (4). There is an inclined perforated plate (5) fit in the cylinder along with the chute in such a way that the newly formed capsules descends, hit the perforated plate and comes out of the chute. The cooling oil does not require to put additional force to push the tender capsules against gravity. Rather, the capsules get discharged from the cylinder by gravity itself. This eliminates the chances of deformation or rupturing of capsules.

The shell forming material melting system as illustrated in figure 5 uses an indirect way to melt the shell forming composition. A heater (1) is fixed at the bottom of the system which heats water (2) and generates steam (3). The heater temperature can be controlled by the control panel (4). An arrangement is provided to fill and adjust the water level in the system (5). The excess water can be drained from the chute (6). The polymer melting tank (7) is placed on a perforated plate (8). The polymer melting tank is fit with compressed air line (9) to push the molten liquid through the transfer line (10). Reference number 11 represents the temperature sensor mounted on the lead to record the melt temperature.

The shell forming solution is highly susceptible to heat. Higher heating temperature for prolonged time can degenerate the polymer. It is seen that the apparatus and process of making shell forming solution can impact the quality of the capsules. The inventors of the present invention provide a design and method for melting the shell forming composition to avoid denaturing of the polymer.

Most of the commercially available melting tank heats the content by electrical heater. These electrical heaters are fit in the jacket of the melting tank and are not highly effective in maintaining the temperature of the content. Moreover, as the viscosity of the shell forming liquid is very high at the beginning of the melting process, the stirring becomes ineffective. The inventors have observed that due to these issues, localized heat spots are generated. These heat spots, having higher temperature than 100 °C, breaks the high molecular weight polymer chains to low molecular weight chains. The low molecular weight chains (due to their lower gel strength), produces capsules with inferior quality. Thus the present invention provides the design of the melting apparatus with indirect heating facility to eliminate localized heating and denaturing of the polymer.

The term, “denaturing of the polymer” refers to the breaking of polymer molecular chains by heat. It has been observed that the shell forming polymer denatures if heated at higher temperature (100 °C and above) for prolonged time and this results in production of capsules with inferior quality, for example, lower hardness, deformation in shape, etc.

To avoid denaturing of the polymer, it has been disclosed the design of a polymer melting system (Figure-5) with indirect heating of the shell forming polymer liquid with the help of steam. This avoids formation of localized heat spot and provides better control in maintaining the melt temperature.

Advantageous features of the present invention:
· The nozzle of the apparatus of the present invention is placed at a height from the surface of the cooling oil to avoid solidification of the polymer resulting in choking of the nozzle.

· The tanks containing shell and core forming liquid shell and core forming material transfer lines and nozzle is equipped with direct / indirect heating system to adjust/ maintain the desired temperature required to match the viscosity requirement of the shell forming solution.

· The compressed air line is fit with pressure reducing valve and PID controller for efficient control of input pressure.

· A solenoid valve is mounted on the tank containing shell forming liquid. The solenoid valve bleeds for few milliseconds in every second and thereby release the pressure build up by the generation of steam. This allows to control the tank pressure effectively.

· The cooling liquid cylinder is design for discharge of the newly formed capsules by gravitational force. Unlike the design disclosed in prior art, this design is energy efficient more practical and user friendly. This design also eliminates the chances of deformation/rupture of the capsules.

· Melting of shell forming composition is done in a melting system equipped with suitable heating facility with the help of stream. The shell melting system is also equipped with a temperature controller. This design allows the shell forming composition to melt gradually without the change of formation of localized heat spot and overheating.

The present invention is now illustrated by means of various non-limiting examples:
Example 1: Method of preparation of gelatin free hard shell seamless capsules:
Capsules were prepared by using the apparatus shown in Figure-1 with the help of shell and core forming liquid.
a. passing shell forming liquid through conduit (4) which ends at the outer nozzle of the concentrically aligned double nozzle (3);
b. passing the core forming liquid through conduit (5), which ends at the inner nozzle of the concentrically aligned double nozzle (3);
c. extruding both the shell and core forming liquid through the concentrically aligned double nozzle to form a spherical shaped capsule (17);
d. dropping the capsule (17) into the cooling liquid cylinder (18) placed at a predetermined height of 5-15 cm from the tip of the concentrically aligned double nozzle (3);
e. straining capsule (17) through an online strainer / separate strainer (20) and collecting the capsules (17); and
f. drying the capsules to attain the acceptable moisture level.

Example 2: Composition of shell and core forming liquid and the Processing conditions for manufacturing capsules
In order to illustrate a working example to manufacture gelatin free hard shell seamless capsule, the following example is presented here.
The target capsule dimension is 3.4-3.6 mm.
The composition of shell and core forming liquid is as below:
Table 1: composition of shell and core forming liquid
For shell
Material Quantity wt%
CarrageenanPotassium ChlorideCalcium Chloride, dihydratePropylene GlycolGreen ColourDemineralized Water 5.550.650.0651.150.00592.5
For Core
Mineral oilApple Flavour 955
The processing condition followed for the capsule manufacturing is as below:
Table 2: processing condition followed for the capsule manufacturing
Shell Polymer melt Temp Core temp Nozzle temp Shell polymer Flow rate Core flow rate Cooling oil temperature Vibration frequency
92±2°C 40±2°C 92±2°C 40 mbar 110mbar 10-15°C 50 Hz

The dimension of the concentrically aligned nozzle is as below:
Table 3: dimension of the concentrically aligned nozzle
Outer Nozzle Inner Nozzle
ID (mm) OD (mm) ID (mm) OD (mm)
3.3 3.5 1.2 1.4

Result and observation: The below table shows the parameters of the capsules obtained when the processing conditions as mentioned above are maintained.

Table 4: parameters of the capsules obtained

Parameters Specification Measurement Process
Mean Range
Capsules size (diameter)(Individual capsules) 3.5 mm 3.4-3.6 mm By profile projector
Capsules roundness(Average of 30 capsules) Not less than 96 % 96-100 % By profile projectorRoundness = (Minor Axis/Major Axis)*100 %
Weight of capsules (Average of 30 capsules) 20 mg 19-21 mg By precision weighing balance
Core weight (Average of 30 capsules) 17.5 mg 17-18 mg By precision weighing balanceCore weight = (Capsule weight-shell weight)

Example 3: cooling liquid cylinder is user friendly and energy efficient
The design of the cooling liquid cylinder disclosed in the prior art (US 7112292 and US 4251195) is such that it requires higher flow rate of the cooling liquid in the cooling liquid cylinder to push the capsules against gravity before discharging the capsules from the cooling liquid cylinder. The inventors of the present invention observed that the design of the cylinder disclosed in the prior art is disadvantageous for tender capsules which are susceptible to mechanical strain. Higher cooling liquid flow rate deforms the tender capsules and in extreme case may rupture the capsules. The inventors of the present invention have provided the design of the cooling liquid cylinder which require lower flow rate of the cooling liquid compare to the prior art (as it does not require to push the capsules against gravity) and thus consumes lesser energy and can be termed as energy efficient.
US 4251195 discloses circulation of cooling liquid at two different temperatures. The present design of the cooling liquid cylinder does not require recirculating two different liquid having different temperature. The inventors of the present invention have found that circulating two different liquid at two different temperatures in the same cooling liquid cylinder is neither user friendly nor practical. The design of the cooling liquid cylinder in the present invention does not require circulating liquids at two different temperature and thus terms as user friendly.

Figure 4 of the present invention (Schematic design of cooling cylinder) illustrates that the outlet is made at the bottom of the tube to collect the capsules. On the contrary, in the prior art, the cooling oil does not require to put additional force to push the tender capsules against gravity (please refer the table with prior art comparison). Rather, the capsules are getting discharged from the cylinder by gravity itself. This justifies energy efficiency. This eliminates the chances of deformation or rupturing of capsules.

Example 4: effect of nozzle height
A set of experiment was conducted by keeping the processing conditions (example 3) and the shell and core formulation (example 2) same. The test was conducted altering the height of the nozzle from the surface of the cooling liquid.

Table 5: Effect of the height of the nozzle from the surface of the cooling liquid on the quality of capsules
Test No. Nozzle height from cooling liquid surface(cm) Roundness of the dried capsules (%)(Average of 30 capsules)Roundness = (Minor Axis/Major Axis)*100%
Test-1 20cm (negative data) 54
Test-1a 3cm (negative data) Capsules never been formed with the desired shape and size
Test-2 10 cm (range: 5-15cm is preferred) 97.5

Result and observation: The inventors found that capsules with desired shape ratio (not less than 96 %) is observed when the nozzle is set between 5-15 cm from the cooling liquid surface.
To eliminate the chance of solidification of the material in the nozzle by getting choked, it is critical to set the nozzle at 10-20 cm height from the cooling liquid surface.
The interpretation here is, when the nozzle height is maintained at 20cm (test 1), it has been observed that only 54% of results are found to be falling under the desired size (capsule roundedness) range 3.4-3.6mm dia. When the nozzle height is reduced to <5cm (test 1a), no capsule is formed with the desired size and shape and hence there is a steep reduction in capsule formation when the nozzle height is not met with the right specs. Whereas when the nozzle height is maintained at 10cm (5-15cm range), it gives almost 98% roundedness of dried capsules and hence it is highly preferred.
Example 5: Set of tests conducted to illustrate the effect to flow rate on quality of the capsules. The tests were conducted keeping the formulation and other processing conditions same as disclosed in example 2

Table 6: effect to flow rate on quality of the capsules
Test No. Capsule production rate Shell solution Flow rate(gm/min) Core flow rate(Peristaltic pump, RPM) Roundness of capsules (%)(Average of 30 capsules)
Test-3 (positive data) 180-200 capsules/min 14.5 3.2 97.5
Test-4 (negative data) 180-200 capsules/min 21 3.4 43
Test-5 (negative data) 180-200 capsules/min 9 3.4 55

Result and observation: The tests concludes that to produce capsules at a rate of 180-200 capsules/min (most preferred capsule size: 3.4-3.6 mm diameter), the flow rate of the shell forming liquid should be maintained at 14.5 gm/min and the flow rate of core forming liquid should be maintained at 3.2 RPM (peristaltic pump speed). Test-4 and 5 are negative experiments to show that when the effect of flow rate (shell solution and core) is altered, it affects the capsule quality (roundedness of capsule / sphericity).

Example 6: The flow rate of shell and core forming liquid and the vibrating frequency decides the size and shape of the capsules. Comparative data to show that change in flow rate of the solution changes the shape and size of the capsules.
Tests were conducted to evaluate the effect of input pressure on the quality of capsules. A set of capsules were prepared based on the conditions mentioned below. The composition of shell and core forming liquid remained same in all the tests. The capsules were analyzed and the results are shown below. The results shows that capsules of different size can be produced by changing the input pressure.
Table 7: Processing condition with change in flow rate
Test No. Shell Polymer melt Temp Core temp Nozzle temp Shell polymer Flow rate Core flow rate Cooling oil temperature Vibration frequency
Test-6 92±2°C 40±2°C 92±2°C 40 mbar 110mbar 10-15°C 50 Hz
Test-7 92±2°C 40±2°C 92±2°C 40 mbar 150mbar 10-15°C 50 Hz
Test-8 92±2°C 40±2°C 92±2°C 60 mbar 110 mbar 10-15°C 50 Hz

Result and observation: the capsules produced under the manufacturing condition according to the above table had the following dimensions/features.

Table 8: resulting parameters

Test No. Size, mm Shape ratio Capsule weight Core weight Hardness
Test-6 5.12 mm >96 % 90.1 mg 80.3 mg 10.8 N
Test-7 5.9 mm >96 % 102.7 mg 93.6 mg 8.7 N
Test-8 4.92 mm >96 % 93.2 mg 78.5 mg 14.3N

The present invention discloses capsule size anywhere between 1-10mm, preferably 3.4-3.6mm, the present invention is capable of producing capsules at different sizes.

For e.g. when the shell polymer flow rate and core flow rates are altered (tests 6,7,8 in the above tables), it is possible to obtain capsules of different sizes like 5.12, 5.9, and 4.9 mm etc. as per the need.

Example 7: Set of tests conducted to illustrate the effect to flow rate on quality of the capsules. The tests were conducted keeping the formulation and other processing conditions same as disclosed in example 2 and 3.

Table 9: Effect to flow rate on quality of the capsules

S No Shell Polymer melt Temp Core temp Nozzle temp Shell polymer Flow rate Core flow rate Cooling oil temp Vibration frequency CapsuleSize mm in dia
Working example 1 92±2°C 40±2°C 92±2°C 40-60mbar 110-150mbar 10-15°C 50Hz 4.9-5.9mm
Negative example 2 92±2°C 40±2°C 92±2°C <40mbar <110mbar 10-15°C 50Hz <1 mm (undesirable)
Negative example 3 92±2°C 40±2°C 92±2°C >60mbar >150mbar 10-15°C 50Hz 11mm (undesirable)

Result and observation: The present invention is capable of producing capsules if 1-10 mm in diameter. In the above example it has been shown with additional examples of 4.9-5.9 mm is also incorporated.
However, negative examples are given to show that when the flow rate (shell polymer flow rate vs. Core flow rate) is used beyond the preferred specs, it would affect the size of the capsules.