Specialty Manufacturerof Powder
and Granular Material Feeders



Frequently asked questions from customers

Listed here are questions about our products (Circle Feeder CF, Loop Feeder LF, etc.) and our services.
If you have a question that is not answered on this page,
feel free to ask us by using this form,
or by phone (Phone: 81-996-26-3388).

Questions about products

  • Why is mass flow possible?

    The vanes rotating near the bottom of the feeder sequentially discharge powder from the entire bottom section of the feeder toward the periphery, thereby achieving ideal mass flow.

  • The driving power is smaller than that of feeders made by other manufacturers. Is that alright?

    Our unique discharge principle allows our feeders to run with less power. The driving power is selected based on actual test results using the same or similar powdered material.

  • Is weight control possible?

    With the control method provided in combination with measuring equipment, batch weighing or continuous weighing of the discharge is possible.

  • Does the capacity change depending on the powder level in the hopper?

    There is hardly any change as long as the powder level remains above the feeder height.
    If the powder level drops below the feeder height, the capacity may drop due to the reduced powder pressure.

  • Can you manufacture using any material?

    We can manufacture using materials specified by the customer. Materials we have used include Hastelloy and titanium.

  • We are going to start a test run. Is there already oil in the speed reducer? Can we start operation as is?

    Oil lubricating speed reducers are normally delivered with no oil. The customer must add the oil before operation.
    When there is no oil, charge the oil before starting operation.
    For grease lubricated models, there is no need to add grease as it has been sealed in. Use it as is. 

  • We would like to use one unit to discharge several different types of materials. Can the material types be changed? To do so, how should the feeder be cleaned?

    The feeder needs to be cleaned when changing the types of powder to be fed, and contamination should be prevented. There are several cleaning methods, including air pressure, wiping, and washing with water. Contact us, as we can offer specifications that meet your needs.

  • What is the accuracy level when using two discharge ports simultaneously?

    If two discharge ports are installed symmetrically, their capacities are almost identical. The margin of error between the discharge ports is roughly 10%, including discharge error.

  • Is the discharge port limited to only one? Is it possible to have two, three or four ports?

    Multiple discharge ports can be installed in accordance with your request, although the installable number depends on the size of the feeder.

  • Is it possible to produce a feeder having a capacity lower (or higher) than that described in the brochure?

    We can design any feeder to meet – the optimum working conditions according to the required capacity.

  • What are the differences between DV, CV, DP, and CP in the model codes?

    Model codes are standardized, based on the shape of the drive section and specifications, so that optimal feeders can be designed according to the operation environment, required functions, installation space, and other factors.

  • What is the largest inlet diameter that can be manufactured?

    The largest inlet diameter of feeders we have manufactured so far is 4000 mm.(157.48″)

  • What is the feeding accuracy level?

    Although the accuracy depends on the physical properties of the materials to be fed, rough standards are 3 to 5% for small feeders and 5 to 6% for large feeders.
    When feeding accuracy is important, the use of our test system is recommended.

  • Can material in the hopper be completely discharged? How much residue will be left, if any?

    Although the situation will vary with the physical properties of the material, there will be some residue on the vanes and bottom plate. However, optional devices to further reduce residue are available. Contact us for details.

  • What is the largest particle size (in mm) that can be discharged?

    The Circle Feeder can discharge particles up to around 50 mm.
    Rocky materials exceeding 50 mm or amorphous materials of around 150 to 200 mm can be discharged by the Loop Feeder.

  • 綿状、繊維状の原料を排出することは出来ますか?


  • What is the maximum compatible capacity and height for the hopper?

    No particular limits have been set.
    If you specify hopper capacity and height, we will propose the optimal inlet diameter and height of the feeder.

  • How is feeding capacity adjusted?

    There are two ways to adjust it.
    One is by adjustment of the flow adjusting ring height, and the other is by changing the rotation speed of the vanes.

  • What is the difference between Type A and Type B in the brochure?

    The difference is the feeding capacity. A is a smaller capacity type, while B has greater capacity.
    The feed rate increases as the width and height of the transporting section increases.

  • What kind of maintenance is required?

    Hardly any daily maintenance is required. For the speed reducer, periodic grease refills or oil changes are necessary. For the shaft of the grand packing type, the packing needs to be tightened or replaced.

  • What is the minimum feeding capacity?

    1 gram/h.

  • Is it airtight?

    The standard type is not airtight. With optional models, we have achieved airtightness up to 0.7 MPa.

  • Is it possible to buy the slide gate alone?

    As it is dedicated gate for the Circle Feeder, it is not sold separately.

  • Can Yoshikawa supply a pneumatic conveying facility in addition to the PTC?

    Please provide us with the specifications, so that we can determine whether we can or not.

  • How long is the conveyance distance?

    40 meters is a rough indication. As the distance can vary depending on the pipe routing, it needs to be reviewed every time the routing is changed.

  • Can you provide engineering for a system?

    We have a track record of delivering many feeding systems, including feeders as the main unit.

  • Can you manufacture hoppers as well?

    We design and manufacture hoppers to meet your requirements.

  • Does the feeder have crushing function?

    By making use of the rotating mechanism of the vanes and adding a modification, we can expect some crushing effect.

  • Is it possible for the feeder to blend and supply?

    Although materials will be blended a little when agitated by the rotary vanes, this will not be as effective as equipment designed especially for blending.

Questions about Sales Overseas

  • In which countries do you have overseas distributors?

    We have distributors in the U.S., Israel, Australia, Italy, and China, but not in other countries.

  • Can you send a supervisor for assembling, installation, test runs and so forth?

    At our customer’s request, we can send our engineers both inside Japan and globally.

  • Can you provide a maintenance service?

    As we have specialists in maintenance, we can provide the service both inside Japan and globally.

Other Questions


Please feel free to contact us for a consultation, inquiry, or request for a quotation regarding our products.
We also accept inquiries by phone or fax.


Phone inquiry hours: 8:30 a.m. to 5:00 p.m. Japan time
(except Saturdays and Sundays)
Fax inquiries can be received at any hour.