FAQ (Frequently Asked Questions)
What differs is the direction in which the air is controlled.
Meter-out Control
For the meter-out control, PISCO Speed Controller ha a letter "A (A□)" engraved on the needle knob, and its lock nut color is silver.
It is primarily used to control the speed of double-acting cylinders*.
It is called "meter-out control" because it regulates the air flow exhausted from the cylinder to control the cylinder speed.
Meter-in Control
For the meter-in control, PISCO Speed Controller has a letter "B (B□)" engraved on the needle knob, and its lock nut color is black.
It is primarily used to control the speed of single-acting cylinders*.
It is called “meter-in control” because it regulates the air flow supplied to the cylinder to control the cylinder speed.
*Double-acting cylinders and Single-acting cylinders
A double-acting cylinder is designed to supply air pressure to both ends of the piston to move it in a reciprocating motion. By attaching a meter-out control type (A) to both ports of the cylinder, you can independently regulate the speed of extension and retraction.
A single-acting cylinder is designed to supply air pressure to only one port of the piston. It uses the force of the load itself or the internal spring for retraction. It is often used with a meter-in control type (B) attached to the supply port of the cylinder to control the cylinder speed in one direction.
Generally, meter-out control provides more stable movements than meter-in control.
Meter-in control adjusts the air flow supplied to the cylinder. In this circuit, as the exhaust side is at atmospheric pressure, the cylinder’s internal pressure gradually increases from atmospheric level, causing instability.
As to meter-out control, compressed air fills the supply and exhaust ports of the cylinder separated by the piston, thereby stabilizing the movement of the cylinder.
[Video] Meter-out & Meter-in Control
A double-acting air cylinder can supply air to both sides of the piston.
For this type of cylinders, a meter-out control type speed controller is commonly used for speed control.
A meter-out control type speed controller supplies air to the cylinder without regulating its flow (free flow). It controls the flow rate according to the setting on the exhaust side. This mechanism allows for safe and stable speed control. On the other hand, a single-acting cylinder, which utilizes an internal spring for retraction, is often used with a meter-in control.
[Video] Meter-out & Meter-in Control
No, you cannot. To adjust the thrust (driving force) of actuators such as air cylinders, you need to decompress the supply air.
If you cannot decompress the supply air using a regulator, you cannot control the thrust (impelling force) of the cylinder.
Throttling a supply flow rate by a flow control valve such as Speed Controller can only slow down the moving speed of the cylinder. It does not control the thrust of the cylinder.
The products that are designed to control the air flow rate based on the application are collectively called "flow control valves".
PISCO's flow control valves include Speed Controller, Throttle (Needle) Valve, Quick Exhaust Valve (with a needle), Exhaust Port Needle Valve (Seed Control Muffler) and Orifice Fitting. For bidirectional control of air flow rate, Throttle (Needle) Valve is generally used. (The air flow rate can be controlled by opening and closing the needle.)
The official term used by ISO 14743 is "Push-in connectors for thermoplastic tubes". Push-in fittings are designed to connect a plastic tube for air piping. The tube can be securely connected by simply inserting it into the fitting. For disconnection, just pull the tube while pressing down the release-ring on the fitting.
Push-in fittings are applied in various ways, such as by incorporation into speed controllers or valves.
PISCO Throttle (Needle) Valve series and Speed Controller series are both in the control valve categories, and they have similar appearances.
Differences in usage and purpose
Speed Controller: Its purpose is to control the speed of an end actuator (primarily a cylinder).
Throttle (Needle) Valve: Its purpose is to control the air flow rate at various points of the piping.
Speed Controller is used primarily to control the air speed, whereas Throttle (Needle) Valve is used to control the air flow rate.
How to distinguish Speed Controller and Throttle (Needle) Valve
No side groove on the needle knob >>> Speed Controller
Side groove on the needle knob >>> Throttle (Needle) Valve
Differences in function
Speed Controller: It houses a needle valve and a check valve and controls only the air flow in a fixed direction (Air flowing in the reverse direction will be free flow).
Throttle (Needle) Valve: It does not have a check valve. It has only a needle valve and controls the air flow rate in whichever direction the air is supplied.
[Video] Differences between Speed Controller and Throttle (Needle) Valve (in Japanese only)
A regulator is used to reduce air pressure supplied to general devices. A pressure controller is used to save compressed air consumption, etc. When an actuator operates at high pressure, and the secondary pressure varies significantly due to fluctuating primary pressure (at the inlet port), Pressure Controller can be employed to reduce the compressed air only for the return stroke.
How to use Pressure controller
PISCO 2-stage Speed Controller adjusts the cylinder stroke speed in two steps by switching the flow path of the two built-in quick exhaust valves.
[Video] Air movement in 2-stage Speed Controller.
The two quick exhaust valves are referred to as Speed Needle (EX1), which determines the cylinder stroke speed and Cushion Needle (EX2), which determines the shock absorbing strength.
The shock absorption start point is at which the flow path is switched, and Timer Needle (TIM) influences its timing.
Timer Needle adjusts the flow rate during the air exhaust from the tank (room where the air is stored). The more the needle is throttled, the slower the exhaust becomes. Consequently, the switching of the flow path associated with the two quick exhaust valves (the start of shock absorption) will occur at a later timing.
Due to its structure, the start of shock absorption may shift due to the external factors such as applied pressure, pipe diameter and length, increase/decrease of the cylinder’s sliding resistance.
You can identify the control direction by the marking on the main body.
As shown below, we define the marked side of the product as the front and the unmarked side as the reverse. The air flow direction is from right to left as in the picture and illustration.
The marked circuit diagram above indicates a "speed control valve". More specifically, the symbol encircled in orange indicates a needle valve that throttles and adjusts the air flow. The symbol encircled in red indicates a check valve that allows air to flow freely in one direction while stopping it in the reversed direction.
The control direction of air is determined by the orientation of the check valve.*
*) Air unrestrictedly flows through in the direction where the open end of the symbol ">" is facing (or spread). So in this case, right to left.
Based on these in mind,
for the entering air supplied to the cylinder to be free flow (in meter-out control), set the air flow direction and the check valve orientation as shown in picture 1. (Returning air, which is exhausted from the cylinder, is controlled.)
In reverse,
for the returning air from the cylinder to be free flow (in meter-in control), set the air flow direction and the check valve orientation as shown in picture 2. (Entering air, which is supplied to the cylinder, is controlled.)
To achieve this, simply flip Speed Controller from the position shown in picture 1.
Because of how Speed Controller Union Straight type is configured, whether to employ meter-in control or meter-out control rests on the orientation of piping. When installing Speed Controller in the piping system, please check the air flow direction and the check valve orientation.
Since PISCO Push-in Fitting is designed to seal the tube’s outer diameter with an elastic sleeve (seal rubber), a several factors can cause leakage, such as scratches or deformation of the tube and jamming of contaminants.
After all, it is manufactured for use with pressurized air piping systems. It cannot be used in the circuits of gas or liquid that can pose a danger in the event of a leak, nor for inspection equipment that could easily be affected by the slightest leak.
FAQ
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