InfiniSpring® has developed a novel prototype of a vibrating conveyor. Students at SeAMK have followed vibrating conveyor development and supported with the manufacturing drawings and assembly of the vibrating conveyor. Vibrating conveyor was first assembled and tested at SeAMK laboratory to validate design simulations. A Finite Element (FE) simulation model of the vibrating conveyor enables in-depth analysis of the converyor’s mechanical and dynamic behavior, allowing students to see simulated data being compared to prototype testing data. In the future SeAMK students can use vibrating conveyor for studying real life dynamic and vibration phenomena. Students can also practice vibration measurements using the vibrating conveyor.

Vibrating conveyor prototype is incorporating InfiniSpring®-springs in a clever and efficient way. The conveyor is constructed entirely from sheet metal steel, manufactured exclusively using laser cutting. It is powered by an eccentric motor with adjustable speed, and the system allows for changes in both motor RPM and spring angle.

This prototype demonstrates impressive functionality:
At 5300 RPM and a 45-degree spring angle, the conveyor operates with smooth, consistent vibratory motion and effectively conveys materials in a continuous flow. The use of InfiniSpring®-springs enables not only vibration but also contributes to the efficient, integrated design of the entire structure.
InfiniSpring Company will productize vibrating conveyor designs. Ultimately, the goal is to design an optimized and simplified version where the InfiniSpring®-springs become an integral part of the conveyor’s structural frame. We look forward to showcasing the final vibrating conveyor designs later once they are complete.

If you’re interested in integrating InfiniSpring®-springs into your vibratory machinery or dynamic systems, don’t hesitate to contact us. We’re always open to new collaborations and applications.

Photos introducing vibratory conveyor prototype:

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The acoustic product tensile tests with very large plastic deformations made us want to increase the loading speed and to see InfiniSpring® shock load performance. InfiniSpring® 3HS20 was chosen for the tests. It is cut out of a 3 mm thick sheet metal plate, weighting only 38 grams. This spring can carry loads up to 20 kg.

In the shock tests a chain is connected to the spring and on the other end of the chain there is a 9 kg mass. InfiniSpring® 3HS20 can carry the 9 kg static mass easily. In the shock test this mass is first lifted higher and then dropped in order to gain an impact force for the spring. Spring deforms due to this impact and reduces the impact force significantly. Tests and test results are shown in the video below:

InfiniSpring® 3HS20 tests and tests results concluded:

Test 1:
• Dropped mass is 9 kg
• Drop height is 1 meter
• The spring length increases 50 mm
• The spring absorbs 90 Joules of energy

Test 2:
• Dropped mass is 9 kg
• Drop height is 2 meters
• The spring length increases 110 mm
• The spring absorbs 170 Joules of energy

InfiniSpring® laser cut sheet metal steel springs are highly effective against shock loads. Shock loads need to be managed, for example in explosions and seismic events.

The post InfiniSpring® Performance Testing – Shock Loads appeared first on InfiniSpring.

We wanted to test InfiniSpring®-springs in overload situations, where load is clearly above the nominal load. We heard from the spring researchers that creep-aging would be fastest during the first three weeks of the testing. After the three week period creep-aging should not be an issue. InfiniSpring® Acoustic Wall Tie 128NN was chosen for the tests. AWT128NN is for nominal loads up to 25 kg.

AWT128NN springs were tested using tensile load. Two springs were overloaded using 30,7 kg and 41,4 kg weights. Initial openings were measured after the loads were applied. For the 30,7 kg weight the initial opening was 7,0 mm and for the 41,4 kg weight 7,9 mm. Initial openings without the loads were 3,9 mm for both springs. Figure 1 shows the spring with tensile overload.

Figure 1. AWT128NN spring overloaded and with a 7,0 mm opening.

Static tensile overload tests started 18.6.2024 and spring openings were measured regularly. Openings remained the same during the tests. After six weeks of testing 1.8.2024 loads were released, and openings were measured to see the plastic deformation magnitude. It can be seen from 1.8.2024 measurement that the initial no load openings have grown slightly from the original: 30,7 kg load from 3,9 mm to 4,2 mm and 41,4 kg load from 3,9 mm to 4,5 mm. This is since the springs are overloaded and yield strength is exceeded in both overload cases. Table 1 below shows all results.

Table 1: Static tensile load test results 18.6.-1.10.2024

Table 1 results show that the openings have remained the same with the overloads. After 1.8.2024 spring 2 was removed and tests were continued for the spring 1 with 30,7 kg load. This test is continued and last check was made 1.10.2024 and spring 1 opening was initial 7,0 mm.

These results indicate that InfiniSpring®-springs can manage static overloads. The spring openings remained the same throughout the testing and no creep-aging was noticed. InfiniSpring®-spring and chosen steel grade seem to perform extremely well even with the static overloads.

The post InfiniSpring® Performance Testing – Static Overload appeared first on InfiniSpring.

Similar tests have been also completed for acoustic wall ties. Acoustic wall ties are not equipped with a fail-safe system and the video below shows the final failure mechanism for an Acoustic Wall Tie AWT94NA. The test revealed that InfiniSpring®-spring has extremely large plastic deformation capacity. The spring stretches similarly as a chewing gum and it has a new shape after the test. The spring does not fail, and the final failure occurs as the acoustic wall tie riveted joint failed on a load level of 210 kg (8 x nominal load).

These highly positive test results for the acoustic products have made us to test InfiniSpring®-springs even more. We have now more recently tested overload and shock load capacity for the springs. We will present these test results also shortly.

The post InfiniSpring® Overload Performance Testing – Tensile Tests appeared first on InfiniSpring.

The test case fan is equipped with a 2.2 kW electric motor, which is controlled via variable-frequency drive. The motor nominal speed is 1440 rpm. The fan is used in air handling units and typically equipped with rubber elements. In this article InfiniSpring®-springs are dimensioned below the fan.

Fan weight

The fan weight was first measured to determine spring selection. Measurement results were taken below the existing rubber elements and measurement results are shown in Figure 1.

Figure 1. Weight measurement results for the fan.

Spring selection

The fan originally had four springs and four InfiniSpring®-springs were chosen to be used in the fan. Spring selection can be made with following steps:

• Calculating total mass: 17.0 kg + 17.0 kg + 23.0 kg + 23.0 kg = 80.0 kg
• Deciding required number of springs: 4
• Calculation load for one individual spring: 80 kg / 4 = 20 kg
• Choosing optimal spring based on the individual spring load: 3HS20 spring with nominal load range 15-20 kg according to Table 1 below (table is taken from the datasheet found on the Product page)

Table 1. Vertical nominal loads of a single spring from the datasheet.

Spring locations

Final step is to dimension springs symmetrically around the center of gravity in the fan axial direction. Fan motor axial direction is referred as X-direction in Figure 2. The zero-point location is also shown in Figure 2.

Figure 2. Fan equipped with original rubber elements.

First the centre of mass x-coordinate is calculated. After this the location for the motor end spring is chosen. In this case 65 mm from the end of the 584 mm long attachment aluminum bar is used, Figure 3. Spring locations from the zero-point location are then calculated as follows.

Calculation steps

• Calculating centre of mass x-coordinate:

• Deciding motor end spring location: 65 mm
• Calculating spring locations:

Figure 3. Spring locations

Fan with new springs

Fan with 3HS20 InfiniSpring® is shown below in Figure 4. Individual InfiniSpring® is shown in Figure 5. Optimal springs were selected for the fan and the fan is ready for operation. Safe operational speed ranges from 755 rpm upwards. Minimum operational speeds can be found from the Data Sheet and also shown in Table 1 above. Please see also a video below introducing the fan and InfiniSpring®-springs.

Figure 4. Fan equipped with 3HS20 InfiniSpring®

The post How to select InfiniSpring® for a fan? appeared first on InfiniSpring.

Test case fan is equipped with 3HS20 InfiniSpring®-springs and with a 2.2 kW electric motor, which is controlled via variable-frequency drive. Motor nominal speed is 1440 rpm. This article focuses on testing the fan with big unbalance to see which rigid body modes are harmful for the fan installation. A fan with a big impeller unbalance mass (extra bolt) is shown in Figure 1 below.

Figure 1. Fan impeller with big unbalance mass.

Completed Test

The fan was tested with a big unbalance mass in different rigid body mode (flexible installation natural mode) resonances by setting the motor speed to measure natural mode frequency of the flexible installation. In practice the fan speed was set first to fan longitudinal mode frequency 4.5 Hz (270 rpm) and fan vibration levels were checked. After this, the speed was raised to fan transversal mode frequency 4.75 Hz (285 rpm) and again fan vibration levels were checked. This was continued all the way up to the last natural mode. In total there are always six degrees of motion (3 translation degrees of freedom and 3 rotating degrees). Below are shown six tested rigid body natural modes and their frequencies.

Test with big unbalance

The test revealed that only transversal and vertical natural modes are excited with big unbalance. Other rigid body natural modes are not excited. Below is a video showing the fan is speeded up from 0 Hz to vertical mode 9.5 Hz (570 rpm) with a very big impeller unbalance. The fan vertical rigid body mode is excited heavily in the vertical direction.

With InfiniSpring® vertical rigid body mode always has a higher natural frequency compared to transversal rigid body mode. Due to this, the vertical rigid body mode defines the minimum operating frequency for the fan. For the fan that was tested, the vertical rigid body mode is 9.5 Hz (570 rpm) and transversal rigid body mode is 4.75 Hz (285 rpm).

Conclusions

Based on the test transversal and vertical rigid body modes for the fan are excited with big unbalance. They are therefore the most harmful rigid body modes. Other rigid body modes are not excited.

Vertical rigid body mode frequency is always higher than transversal mode frequency. Due to this, the vertical rigid body mode frequency is used for dimensioning InfiniSpring®-springs for a fan, and it also defines the fan minimum operating frequency.

Datasheet values can be used to define minimum operating frequency. The datasheet defines the minimum rotational speed, e.g. 3HS20 InfiniSpring® is for rotational speeds above 755 rpm (12.6 Hz). The rpm value can be found from the datasheet.

P.S. In this case, the fan can be operated safely in a speed range from 755 rpm up to the speed allowed by the fan or motor.

P.P.S. With the balanced fan, none of the rigid body modes were excited and it was safe to operate the fan from 0 rpm upwards.

The post Which frequencies are harmful for fan installations and what is fan’s minimum operating frequency? appeared first on InfiniSpring.

The test case fan is equipped with 3HS20 InfiniSpring®-springs and a 2.2 kW electric motor, which is controlled via variable-frequency drive. The motor nominal speed is 1440 rpm. The fan is used in air handling units and typically equipped with rubber elements. This article focuses on validating InfiniSpring®-spring selection based on the fan weight data. Fan with 3HS20 InfiniSpring® is shown in Figure 1 below.

Datasheet Data for 3HS20 Spring

According to technical datasheet 3HS20 spring is for nominal load ranges between 15-20 kg and for rotational speeds above 755 rpm. Maximum vertical natural frequency is less than 11.7 Hz, Table 1 below.

Table 1. Maximum vertical natural frequencies when using nominal load range.

Natural Frequency Validations

The vertical natural frequency was measured to validate the limit value 11.7 Hz. The measured vertical natural frequency result is shown below in Table 2 together with the datasheet limit value.

Table 2. Measured vertical natural frequency.

In order to comply with the data sheet value, the measured value needs to be below the datasheet frequency 11.7 Hz for vertical natural mode. Based on the 9.5 Hz measurement result we are clearly on a safe side. It is to be noted that the test case fan 3HS20 InfiniSpring® is for a load range of 15-20 kg and the spring load is 20 kg. This means that 15 kg spring load would give vertical natural frequency of approximately 10.5 Hz and the result would be safe with lower load.

Conclusions

Based on the measurement the vertical mode frequency for the test case fan 3HS20 InfiniSpring® is from 9.5 Hz to 10.5 Hz and vertical mode frequency is always safely below the datasheet value 11.7 Hz. Weight data can be used very safely for the spring selection.

Fan and InfiniSpring®-springs introduced below.

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